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{{task}}Code Generator
A code generator translates the output of the syntax analyzer and/or semantic analyzer into lower level code, either assembly, object, or virtual.
{{task heading}}
Take the output of the Syntax analyzer [[Compiler/syntax_analyzer|task]] - which is a [[Flatten_a_list|flattened]] Abstract Syntax Tree (AST) - and convert it to virtual machine code, that can be run by the [[Compiler/virtual_machine_interpreter|Virtual machine interpreter]]. The output is in text format, and represents virtual assembly code.
The program should read input from a file and/or stdin, and write output to a file and/or stdout.
;Example - given the simple program (below), stored in a file called while.t, create the list of tokens, using one of the Lexical analyzer [[Compiler/lexical_analyzer|solutions]]
lex < while.t > while.lex
;Run one of the Syntax analyzer [[Compiler/syntax_analyzer|solutions]]:
parse < while.lex > while.ast
;while.ast can be input into the code generator.
;The following table shows the input to lex, lex output, the AST produced by the parser, and the generated virtual assembly code.
Run as: lex < while.t | parse | gen
{| class="wikitable" |- ! Input to lex ! Output from lex, input to parse ! Output from parse ! Output from gen, input to VM |- | style="vertical-align:top" |
count = 1;
while (count < 10) {
print("count is: ", count, "\n");
count = count + 1;
}
| style="vertical-align:top" |
1 1 Identifier count
1 7 Op_assign
1 9 Integer 1
1 10 Semicolon
2 1 Keyword_while
2 7 LeftParen
2 8 Identifier count
2 14 Op_less
2 16 Integer 10
2 18 RightParen
2 20 LeftBrace
3 5 Keyword_print
3 10 LeftParen
3 11 String "count is: "
3 23 Comma
3 25 Identifier count
3 30 Comma
3 32 String "\n"
3 36 RightParen
3 37 Semicolon
4 5 Identifier count
4 11 Op_assign
4 13 Identifier count
4 19 Op_add
4 21 Integer 1
4 22 Semicolon
5 1 RightBrace
6 1 End_of_input
| style="vertical-align:top" |
Sequence
Sequence
;
Assign
Identifier count
Integer 1
While
Less
Identifier count
Integer 10
Sequence
Sequence
;
Sequence
Sequence
Sequence
;
Prts
String "count is: "
;
Prti
Identifier count
;
Prts
String "\n"
;
Assign
Identifier count
Add
Identifier count
Integer 1
| style="vertical-align:top" |
Datasize: 1 Strings: 2
"count is: "
"\n"
0 push 1
5 store [0]
10 fetch [0]
15 push 10
20 lt
21 jz (43) 65
26 push 0
31 prts
32 fetch [0]
37 prti
38 push 1
43 prts
44 fetch [0]
49 push 1
54 add
55 store [0]
60 jmp (-51) 10
65 halt
; Input format:
As shown in the table, above, the output from the [[Compiler/syntax_analyzer|syntax analyzer]] is a flattened AST.
In the AST, Identifier, Integer, and String, are terminal nodes, e.g, they do not have child nodes.
Loading this data into an internal parse tree should be as simple as:
def load_ast()
line = readline()
# Each line has at least one token
line_list = tokenize the line, respecting double quotes
text = line_list[0] # first token is always the node type
if text == ";"
return None
node_type = text # could convert to internal form if desired
# A line with two tokens is a leaf node
# Leaf nodes are: Identifier, Integer String
# The 2nd token is the value
if len(line_list) > 1
return make_leaf(node_type, line_list[1])
left = load_ast()
right = load_ast()
return make_node(node_type, left, right)
; Output format - refer to the table above
- The first line is the header: Size of data, and number of constant strings. ** size of data is the number of 32-bit unique variables used. In this example, one variable, '''count''' ** number of constant strings is just that - how many there are
- After that, the constant strings
- Finally, the assembly code
;Registers:
-
sp: the stack pointer - points to the next top of stack. The stack is a 32-bit integer array.
-
pc: the program counter - points to the current instruction to be performed. The code is an array of bytes.
;Data:
32-bit integers and strings
;Instructions:
Each instruction is one byte. The following instructions also have a 32-bit integer operand:
fetch [index]
where index is an index into the data array.
store [index]
where index is an index into the data array.
push n
where value is a 32-bit integer that will be pushed onto the stack.
jmp (n) addr
where (n) is a 32-bit integer specifying the distance between the current location and the desired location. addr is an unsigned value of the actual code address.
jz (n) addr
where (n) is a 32-bit integer specifying the distance between the current location and the desired location. addr is an unsigned value of the actual code address.
The following instructions do not have an operand. They perform their operation directly against the stack:
For the following instructions, the operation is performed against the top two entries in the stack:
add sub mul div mod lt gt le ge eq ne and or
For the following instructions, the operation is performed against the top entry in the stack:
neg not
prtc
Print the word at stack top as a character.
prti
Print the word at stack top as an integer.
prts
Stack top points to an index into the string pool. Print that entry.
halt
Unconditional stop.
; Additional examples
Your solution should pass all the test cases above and the additional tests found '''[[Compiler/Sample_programs|Here]]'''.
{{task heading|Reference}}
The C and Python versions can be considered reference implementations.
;Related Tasks
- [[Compiler/lexical_analyzer|Lexical Analyzer task]]
- [[Compiler/syntax_analyzer|Syntax Analyzer task]]
- [[Compiler/virtual_machine_interpreter|Virtual Machine Interpreter task]]
- [[Compiler/AST_interpreter|AST Interpreter task]]
__TOC__
ALGOL 68
Based on the Algol W sample. This generates .NET IL assembler code which can be compiled with the .NET ilasm assembler to generate an exe that can be run under Windows (and presumably Mono though I haven't tried that).
Apart from the namespace, class and method blocks surrounding the code, the main differences between IL and the task's assembly code are: no "compare-le", "compare-ge", "compare-ne", "prts", "prtc", "prti" and "not" instructions, symbolic labels are used and symbolic local variable names can be used. Some IL instructions have different names, e.g. "stloc" instead of "store". The "prt*" instructions are handled by calling the relevant System.Out.Print method. The compare and "not" instructions are handled by generating equivalent instruction sequences.
As noted in the code, the generated IL is naive - the sample focuses on simplicity.
# RC Compiler code generator #
COMMENT
this writes a .NET IL assembler source to standard output.
If the output is stored in a file called "rcsample.il",
it could be compiled the command:
ilasm /opt /out:rcsample.exe rcsample.il
(Note ilasm may not be in the PATH by default(
Note: The generated IL is *very* naive
COMMENT
# parse tree nodes #
MODE NODE = STRUCT( INT type, REF NODE left, right, INT value );
INT nidentifier = 1, nstring = 2, ninteger = 3, nsequence = 4, nif = 5, nprtc = 6, nprts = 7
, nprti = 8, nwhile = 9, nassign = 10, nnegate = 11, nnot = 12, nmultiply = 13, ndivide = 14
, nmod = 15, nadd = 16, nsubtract = 17, nless = 18, nlessequal = 19, ngreater = 20
, ngreaterequal = 21, nequal = 22, nnotequal = 23, nand = 24, nor = 25
;
# op codes #
INT ofetch = 1, ostore = 2, opush = 3, oadd = 4, osub = 5, omul = 6, odiv = 7, omod = 8
, olt = 9, ogt = 10, ole = 11, oge = 12, oeq = 13, one = 14, oand = 15, oor = 16
, oneg = 17, onot = 18, ojmp = 19, ojz = 20, oprtc = 21, oprts = 22, oprti = 23, opushstr = 24
;
[]INT ndop
= ( -1 , -1 , -1 , -1 , -1 , -1 , -1
, -1 , -1 , -1 , oneg , -1 , omul , odiv
, omod , oadd , osub , olt , -1 , ogt
, -1 , oeq , -1 , oand , oor
) ;
[]STRING ndname
= ( "Identifier" , "String" , "Integer" , "Sequence" , "If" , "Prtc" , "Prts"
, "Prti" , "While" , "Assign" , "Negate" , "Not" , "Multiply" , "Divide"
, "Mod" , "Add" , "Subtract" , "Less" , "LessEqual" , "Greater"
, "GreaterEqual" , "Equal" , "NotEqual" , "And" , "Or"
) ;
[]STRING opname
= ( "ldloc ", "stloc ", "ldc.i4 ", "add ", "sub ", "mul ", "div ", "rem "
, "clt ", "cgt ", "?le ", "?ge ", "ceq ", "?ne ", "and ", "or "
, "neg ", "?not ", "br ", "brfalse", "?prtc ", "?prts ", "?prti ", "ldstr "
) ;
# string and identifier arrays - a hash table might be better... #
INT max string number = 1024;
[ 0 : max string number ]STRING identifiers, strings;
FOR s pos FROM 0 TO max string number DO
identifiers[ s pos ] := "";
strings [ s pos ] := ""
OD;
# label number for label generation #
INT next label number := 0;
# returns the next free label number #
PROC new label = INT: next label number +:= 1;
# returns a new node with left and right branches #
PROC op node = ( INT op type, REF NODE left, right )REF NODE: HEAP NODE := NODE( op type, left, right, 0 );
# returns a new operand node #
PROC operand node = ( INT op type, value )REF NODE: HEAP NODE := NODE( op type, NIL, NIL, value );
# reports an error and stops #
PROC gen error = ( STRING message )VOID:
BEGIN
print( ( message, newline ) );
stop
END # gen error # ;
# reads a node from standard input #
PROC read node = REF NODE:
BEGIN
REF NODE result := NIL;
# parses a string from line and stores it in a string in the text array #
# - if it is not already present in the specified textElement list. #
# returns the position of the string in the text array #
PROC read string = ( REF[]STRING text list, CHAR terminator )INT:
BEGIN
# get the text of the string #
STRING str := line[ l pos ];
l pos +:= 1;
WHILE IF l pos <= UPB line THEN line[ l pos ] /= terminator ELSE FALSE FI DO
str +:= line[ l pos ];
l pos +:= 1
OD;
IF l pos > UPB line THEN gen error( "Unterminated String in node file: (" + line + ")." ) FI;
# attempt to find the text in the list of strings/identifiers #
INT t pos := LWB text list;
BOOL found := FALSE;
INT result := LWB text list - 1;
FOR t pos FROM LWB text list TO UPB text list WHILE NOT found DO
IF found := text list[ t pos ] = str THEN
# found the string #
result := t pos
ELIF text list[ t pos ] = "" THEN
# have an empty slot for ther string #
found := TRUE;
text list[ t pos ] := str;
result := t pos
FI
OD;
IF NOT found THEN gen error( "Out of string space." ) FI;
result
END # read string # ;
# gets an integer from the line - no checks for valid digits #
PROC read integer = INT:
BEGIN
INT n := 0;
WHILE line[ l pos ] /= " " DO
( n *:= 10 ) +:= ( ABS line[ l pos ] - ABS "0" );
l pos +:= 1
OD;
n
END # read integer # ;
STRING line, name;
INT l pos := 1, nd type := -1;
read( ( line, newline ) );
line +:= " ";
# get the node type name #
WHILE line[ l pos ] = " " DO l pos +:= 1 OD;
name := "";
WHILE IF l pos > UPB line THEN FALSE ELSE line[ l pos ] /= " " FI DO
name +:= line[ l pos ];
l pos +:= 1
OD;
# determine the node type #
nd type := LWB nd name;
IF name /= ";" THEN
# not a null node #
WHILE IF nd type <= UPB nd name THEN name /= nd name[ nd type ] ELSE FALSE FI DO nd type +:= 1 OD;
IF nd type > UPB nd name THEN gen error( "Malformed node: (" + line + ")." ) FI;
# handle the additional parameter for identifier/string/integer, or sub-nodes for operator nodes #
IF nd type = ninteger OR nd type = nidentifier OR nd type = nstring THEN
WHILE line[ l pos ] = " " DO l pos +:= 1 OD;
IF nd type = ninteger THEN result := operand node( nd type, read integer )
ELIF nd type = nidentifier THEN result := operand node( nd type, read string( identifiers, " " ) )
ELSE # nd type = nString # result := operand node( nd type, read string( strings, """" ) )
FI
ELSE
# operator node #
REF NODE left node = read node;
result := op node( nd type, left node, read node )
FI
FI;
result
END # read node # ;
# returns a formatted op code for code generation #
PROC operation = ( INT op code )STRING: " " + op name[ op code ] + " ";
# defines the specified label #
PROC define label = ( INT label number )VOID: print( ( "lbl_", whole( label number, 0 ), ":", newline ) );
# generates code to load a string value #
PROC gen load string = ( INT value )VOID:
BEGIN
print( ( operation( opushstr ), " ", strings[ value ], """", newline ) )
END # push string # ;
# generates code to load a constant value #
PROC gen load constant = ( INT value )VOID: print( ( operation( opush ), " ", whole( value, 0 ), newline ) );
# generates an operation acting on an address #
PROC gen data op = ( INT op, address )VOID: print( ( operation( op ), " l_", identifiers[ address ], newline ) );
# generates a nullary operation #
PROC gen op 0 = ( INT op )VOID: print( ( operation( op ), newline ) );
# generates a "not" instruction sequence #
PROC gen not = VOID:
BEGIN
gen load constant( 0 );
print( ( operation( oeq ), newline ) )
END # gen not # ;
# generates a negated condition #
PROC gen not op = ( INT op, REF NODE n )VOID:
BEGIN
gen( left OF n );
gen( right OF n );
gen op 0( op );
gen not
END # gen not op # ;
# generates a jump operation #
PROC gen jump = ( INT op, label )VOID: print( ( operation( op ), " lbl_", whole( label, 0 ), newline ) );
# generates code to output something to System.Console.Out #
PROC gen output = ( REF NODE n, STRING output type )VOID:
BEGIN
print( ( " call " ) );
print( ( "class [mscorlib]System.IO.TextWriter [mscorlib]System.Console::get_Out()", newline ) );
gen( left OF n );
print( ( " callvirt " ) );
print( ( "instance void [mscorlib]System.IO.TextWriter::Write(", output type, ")", newline ) )
END # gen output # ;
# generates the code header - assembly info, namespace, class and start of the Main method #
PROC code header = VOID:
BEGIN
print( ( ".assembly extern mscorlib { auto }", newline ) );
print( ( ".assembly RccSample {}", newline ) );
print( ( ".module RccSample.exe", newline ) );
print( ( ".namespace Rcc.Sample", newline ) );
print( ( "{", newline ) );
print( ( " .class public auto ansi Program extends [mscorlib]System.Object", newline ) );
print( ( " {", newline ) );
print( ( " .method public static void Main() cil managed", newline ) );
print( ( " {", newline ) );
print( ( " .entrypoint", newline ) );
# output the local variables #
BOOL have locals := FALSE;
STRING local prefix := " .locals init (int32 l_";
FOR s pos FROM LWB identifiers TO UPB identifiers WHILE identifiers[ s pos ] /= "" DO
print( ( local prefix, identifiers[ s pos ], newline ) );
local prefix := " ,int32 l_";
have locals := TRUE
OD;
IF have locals THEN
# there were some local variables defined - output the terminator #
print( ( " )", newline ) )
FI
END # code header # ;
# generates code for the node n #
PROC gen = ( REF NODE n )VOID:
IF n IS REF NODE( NIL ) THEN # null node #
SKIP
ELIF type OF n = nidentifier THEN # load identifier #
gen data op( ofetch, value OF n )
ELIF type OF n = nstring THEN # load string #
gen load string( value OF n )
ELIF type OF n = ninteger THEN # load integer #
gen load constant( value OF n )
ELIF type OF n = nsequence THEN # list #
gen( left OF n );
gen( right OF n )
ELIF type OF n = nif THEN # if-else #
INT else label := new label;
gen( left OF n );
gen jump( ojz, else label );
gen( left OF right OF n );
IF right OF right OF n IS REF NODE( NIL ) THEN
# no "else" part #
define label( else label )
ELSE
# have an "else" part #
INT end if label := new label;
gen jump( ojmp, end if label );
define label( else label );
gen( right OF right OF n );
define label( end if label )
FI
ELIF type OF n = nwhile THEN # while-loop #
INT loop label := new label;
INT exit label := new label;
define label( loop label );
gen( left OF n );
gen jump( ojz, exit label );
gen( right OF n );
gen jump( ojmp, loop label );
define label( exit label )
ELIF type OF n = nassign THEN # assignment #
gen( right OF n );
gen data op( ostore, value OF left OF n )
ELIF type OF n = nnot THEN # bolean not #
gen( left OF n );
gen not
ELIF type OF n = ngreaterequal THEN # compare >= #
gen not op( olt, n )
ELIF type OF n = nnotequal THEN # compare not = #
gen not op( oeq, n )
ELIF type OF n = nlessequal THEN # compare <= #
gen not op( ogt, n )
ELIF type OF n = nprts THEN # print string #
gen output( n, "string" )
ELIF type OF n = nprtc THEN # print character #
gen output( n, "char" )
ELIF type OF n = nprti THEN # print integer #
gen output( n, "int32" )
ELSE # everything else #
gen( left OF n );
gen( right OF n ); # right will be null for a unary op so no code will be generated #
print( ( operation( ndop( type OF n ) ), newline ) )
FI # gen # ;
# generates the code trailer - return instruction, end of Main method, end of class and end of namespace #
PROC code trailer = VOID:
BEGIN
print( ( " ret", newline ) );
print( ( " } // Main method", newline ) );
print( ( " } // Program class", newline ) );
print( ( "} // Rcc.Sample namespace", newline ) )
END # code trailer # ;
# parse the output from the syntax analyser and generate code from the parse tree #
REF NODE code = read node;
code header;
gen( code );
code trailer
{{out}}
.assembly extern mscorlib { auto }
.assembly RccSample {}
.module RccSample.exe
.namespace Rcc.Sample
{
.class public auto ansi Program extends [mscorlib]System.Object
{
.method public static void Main() cil managed
{
.entrypoint
.locals init (int32 l_count
)
ldc.i4 1
stloc l_count
lbl_1:
ldloc l_count
ldc.i4 10
clt
brfalse lbl_2
call class [mscorlib]System.IO.TextWriter [mscorlib]System.Console::get_Out()
ldstr "count is: "
callvirt instance void [mscorlib]System.IO.TextWriter::Write(string)
call class [mscorlib]System.IO.TextWriter [mscorlib]System.Console::get_Out()
ldloc l_count
callvirt instance void [mscorlib]System.IO.TextWriter::Write(int32)
call class [mscorlib]System.IO.TextWriter [mscorlib]System.Console::get_Out()
ldstr "\n"
callvirt instance void [mscorlib]System.IO.TextWriter::Write(string)
ldloc l_count
ldc.i4 1
add
stloc l_count
br lbl_1
lbl_2:
ret
} // Main method
} // Program class
} // Rcc.Sample namespace
ALGOL W
begin % code generator %
% parse tree nodes %
record node( integer type
; reference(node) left, right
; integer iValue % nString/nIndentifier number or nInteger value %
);
integer nIdentifier, nString, nInteger, nSequence, nIf, nPrtc, nPrts
, nPrti, nWhile, nAssign, nNegate, nNot, nMultiply
, nDivide, nMod, nAdd, nSubtract, nLess, nLessEqual
, nGreater, nGreaterEqual, nEqual, nNotEqual, nAnd, nOr
;
string(14) array ndName ( 1 :: 25 );
integer array nOp ( 1 :: 25 );
integer MAX_NODE_TYPE;
% string literals and identifiers - uses a linked list - a hash table might be better... %
string(1) array text ( 0 :: 4095 );
integer textNext, TEXT_MAX;
record textElement ( integer start, length; reference(textElement) next );
reference(textElement) idList, stList;
% op codes %
integer oFetch, oStore, oPush
, oAdd, oSub, oMul, oDiv, oMod, oLt, oGt, oLe, oGe, oEq, oNe
, oAnd, oOr, oNeg, oNot, oJmp, oJz, oPrtc, oPrts, oPrti, oHalt
;
string(6) array opName ( 1 :: 24 );
% code - although this is intended to be byte code, as we are going to output %
% an assembler source, we use integers for convenience %
% labelLocations are: - ( referencing location + 1 ) if they have been referenced but not defined yet, %
% zero if they are unreferenced and undefined, %
% ( referencing location + 1 ) if they are defined %
integer array byteCode ( 0 :: 4095 );
integer array labelLocation( 1 :: 4096 );
integer nextLocation, MAX_LOCATION, nextLabelNumber, MAX_LABEL_NUMBER;
% returns a new node with left and right branches %
reference(node) procedure opNode ( integer value opType; reference(node) value opLeft, opRight ) ; begin
node( opType, opLeft, opRight, 0 )
end opNode ;
% returns a new operand node %
reference(node) procedure operandNode ( integer value opType, opValue ) ; begin
node( opType, null, null, opValue )
end operandNode ;
% reports an error and stops %
procedure genError( string(80) value message ); begin
integer errorPos;
write( s_w := 0, "**** Code generation error: " );
errorPos := 0;
while errorPos < 80 and message( errorPos // 1 ) not = "." do begin
writeon( s_w := 0, message( errorPos // 1 ) );
errorPos := errorPos + 1
end while_not_at_end_of_message ;
writeon( s_w := 0, "." );
assert( false )
end genError ;
% reads a node from standard input %
reference(node) procedure readNode ; begin
reference(node) resultNode;
% parses a string from line and stores it in a string in the text array %
% - if it is not already present in the specified textElement list. %
% returns the position of the string in the text array %
integer procedure readString ( reference(textElement) value result txList; string(1) value terminator ) ; begin
string(256) str;
integer sLen, sPos, ePos;
logical found;
reference(textElement) txPos, txLastPos;
% get the text of the string %
str := " ";
sLen := 0;
str( sLen // 1 ) := line( lPos // 1 );
sLen := sLen + 1;
lPos := lPos + 1;
while lPos <= 255 and line( lPos // 1 ) not = terminator do begin
str( sLen // 1 ) := line( lPos // 1 );
sLen := sLen + 1;
lPos := lPos + 1
end while_more_string ;
if lPos > 255 then genError( "Unterminated String in node file." );
% attempt to find the text in the list of strings/identifiers %
txLastPos := txPos := txList;
found := false;
ePos := 0;
while not found and txPos not = null do begin
ePos := ePos + 1;
found := ( length(txPos) = sLen );
sPos := 0;
while found and sPos < sLen do begin
found := str( sPos // 1 ) = text( start(txPos) + sPos );
sPos := sPos + 1
end while_not_found ;
txLastPos := txPos;
if not found then txPos := next(txPos)
end while_string_not_found ;
if not found then begin
% the string/identifier is not in the list - add it %
ePos := ePos + 1;
if txList = null then txList := textElement( textNext, sLen, null )
else next(txLastPos) := textElement( textNext, sLen, null );
if textNext + sLen > TEXT_MAX then genError( "Text space exhausted." )
else begin
for cPos := 0 until sLen - 1 do begin
text( textNext ) := str( cPos // 1 );
textNext := textNext + 1
end for_cPos
end
end if_not_found ;
ePos
end readString ;
% gets an integer from the line - no checks for valid digits %
integer procedure readInteger ; begin
integer n;
n := 0;
while line( lPos // 1 ) not = " " do begin
n := ( n * 10 ) + ( decode( line( lPos // 1 ) ) - decode( "0" ) );
lPos := lPos + 1
end while_not_end_of_integer ;
n
end readInteger ;
string(256) line;
string(16) name;
integer lPos, tPos, ndType;
tPos := lPos := 0;
readcard( line );
% get the node type name %
while line( lPos // 1 ) = " " do lPos := lPos + 1;
name := "";
while lPos < 256 and line( lPos // 1 ) not = " " do begin
name( tPos // 1 ) := line( lPos // 1 );
lPos := lPos + 1;
tPos := tPos + 1
end while_more_name ;
% determine the node type %
ndType := 1;
resultNode := null;
if name not = ";" then begin
% not a null node %
while ndType <= MAX_NODE_TYPE and name not = ndName( ndType ) do ndType := ndType + 1;
if ndType > MAX_NODE_TYPE then genError( "Malformed node." );
% handle the additional parameter for identifier/string/integer, or sub-nodes for operator nodes %
if ndType = nInteger or ndType = nIdentifier or ndType = nString then begin
while line( lPos // 1 ) = " " do lPos := lPos + 1;
if ndType = nInteger then resultNode := operandNode( ndType, readInteger )
else if ndType = nIdentifier then resultNode := operandNode( ndType, readString( idList, " " ) )
else % ndType = nString % resultNode := operandNode( ndType, readString( stList, """" ) )
end
else begin
% operator node %
reference(node) leftNode;
leftNode := readNode;
resultNode := opNode( ndType, leftNode, readNode )
end
end if_non_null_node ;
resultNode
end readNode ;
% returns the next free label number %
integer procedure newLabel ; begin
nextLabelNumber := nextLabelNumber + 1;
if nextLabelNumber > MAX_LABEL_NUMBER then genError( "Program too complex" );
nextLabelNumber
end newLabel ;
% defines the specified label to be at the next location %
procedure defineLabel ( integer value labelNumber ) ; begin
if labelLocation( labelNumber ) > 0 then genError( "Label already defined" )
else begin
% this is the first definition of the label, define it and if it has already been referenced, fill in the reference %
integer currValue;
currValue := labelLocation( labelNumber );
labelLocation( labelNumber ) := nextLocation + 1; % we store pc + 1 to ensure the label location is positive %
if currValue < 0 then % already referenced % byteCode( - ( currValue + 1 ) ) := labelLocation( labelNumber )
end
end defineLabel ;
% stores a byte in the code %
procedure genByte ( integer value byteValue ) ; begin
if nextLocation > MAX_LOCATION then genError( "Program too large" );
byteCode( nextLocation ) := byteValue;
nextLocation := nextLocation + 1
end genByte ;
% stores an integer in the code %
procedure genInteger ( integer value integerValue ) ; begin
% we are storing the bytes of the code in separate integers for convenience %
genByte( integerValue ); genByte( 0 ); genByte( 0 ); genByte( 0 )
end genInteger ;
% generates an operation acting on an address %
procedure genDataOp ( integer value opCode, address ) ; begin
genByte( opCode );
genInteger( address )
end genDataOp ;
% generates a nullary operation %
procedure genOp0 ( integer value opCode ) ; begin
genByte( opCode )
end genOp0 ;
% generates a unary/binary operation %
procedure genOp ( reference(node) value n ) ; begin
gen( left(n) );
gen( right(n) ); % right will be null for a unary op so no code will be generated %
genByte( nOp( type(n) ) )
end genOp ;
% generates a jump operation %
procedure genJump ( integer value opCode, labelNumber ) ; begin
genByte( opCode );
% if the label is not defined yet - set it's location to the negative of the referencing location %
% so it can be resolved later %
if labelLocation( labelNumber ) = 0 then labelLocation( labelNumber ) := - ( nextLocation + 1 );
genInteger( labelLocation( labelNumber ) )
end genJump ;
% generates code for the node n %
procedure gen ( reference(node) value n ) ; begin
if n = null then % empty node % begin end
else if type(n) = nIdentifier then genDataOp( oFetch, iValue(n) )
else if type(n) = nString then genDataOp( oPush, iValue(n) - 1 )
else if type(n) = nInteger then genDataOp( oPush, iValue(n) )
else if type(n) = nSequence then begin
gen( left(n) );
gen( right(n) )
end
else if type(n) = nIf then % if-else % begin
integer elseLabel;
elseLabel := newLabel;
gen( left(n) );
genJump( oJz, elseLabel );
gen( left( right(n) ) );
if right(right(n)) = null then % no "else" part % defineLabel( elseLabel )
else begin
% have an "else" part %
integer endIfLabel;
endIfLabel := newLabel;
genJump( oJmp, endIfLabel );
defineLabel( elseLabel );
gen( right(right(n)) );
defineLabel( endIfLabel )
end
end
else if type(n) = nWhile then % while-loop % begin
integer loopLabel, exitLabel;
loopLabel := newLabel;
exitLabel := newLabel;
defineLabel( loopLabel );
gen( left(n) );
genJump( oJz, exitLabel );
gen( right(n) );
genJump( oJmp, loopLabel );
defineLabel( exitLabel )
end
else if type(n) = nAssign then % assignment % begin
gen( right( n ) );
genDataOp( oStore, iValue(left(n)) )
end
else genOp( n )
end gen ;
% outputs the generated code to standard output %
procedure emitCode ; begin
% counts the number of elements in a text element list %
integer procedure countElements ( reference(textElement) value txHead ) ; begin
integer count;
reference(textElement) txPos;
count := 0;
txPos := txHead;
while txPos not = null do begin
count := count + 1;
txPos := next(txPos)
end while_txPos_not_null ;
count
end countElements ;
integer pc, op;
reference(textElement) txPos;
% code header %
write( i_w := 1, s_w := 0
, "Datasize: ", countElements( idList )
, " Strings: ", countElements( stList )
);
% output the string literals %
txPos := stList;
while txPos not = null do begin
integer cPos;
write( """" );
cPos := 1; % start from 1 to skip over the leading " %
while cPos < length(txPos) do begin
writeon( s_w := 0, text( start(txPos) + cPos ) );
cPos := cPos + 1
end while_not_end_of_string ;
writeon( s_w := 0, """" );
txPos := next(txPos)
end while_not_at_end_of_literals ;
% code body %
pc := 0;
while pc < nextLocation do begin
op := byteCode( pc );
write( i_w := 4, s_w := 0, pc, " ", opName( op ) );
pc := pc + 1;
if op = oFetch or op = oStore then begin
% data load/store - add the address in square brackets %
writeon( i_w := 1, s_w := 0, "[", byteCode( pc ) - 1, "]" );
pc := pc + 4
end
else if op = oPush then begin
% push constant - add the constant %
writeon( i_w := 1, s_w := 0, byteCode( pc ) );
pc := pc + 4
end
else if op = oJmp or op = oJz then begin
% jump - show the relative address in brackets and the absolute address %
writeon( i_w := 1, s_w := 0, "(", ( byteCode( pc ) - 1 ) - pc, ") ", byteCode( pc ) - 1 );
pc := pc + 4
end
end while_pc_lt_nextLocation
end emitCode ;
oFetch := 1; opName( oFetch ) := "fetch"; oStore := 2; opName( oStore ) := "store"; oPush := 3; opName( oPush ) := "push";
oAdd := 4; opName( oAdd ) := "add"; oSub := 5; opName( oSub ) := "sub"; oMul := 6; opName( oMul ) := "mul";
oDiv := 7; opName( oDiv ) := "div"; oMod := 8; opName( oMod ) := "mod"; oLt := 9; opName( oLt ) := "lt";
oGt := 10; opName( oGt ) := "gt"; oLe := 11; opName( oLe ) := "le"; oGe := 12; opName( oGe ) := "ge";
oEq := 13; opName( oEq ) := "eq"; oNe := 14; opName( oNe ) := "ne"; oAnd := 15; opName( oAnd ) := "and";
oOr := 16; opName( oOr ) := "or"; oNeg := 17; opName( oNeg ) := "neg"; oNot := 18; opName( oNot ) := "not";
oJmp := 19; opName( oJmp ) := "jmp"; oJz := 20; opName( oJz ) := "jz"; oPrtc := 21; opName( oPrtc ) := "prtc";
oPrts := 22; opName( oPrts ) := "prts"; oPrti := 23; opName( oPrti ) := "prti"; oHalt := 24; opName( oHalt ) := "halt";
nIdentifier := 1; ndName( nIdentifier ) := "Identifier"; nString := 2; ndName( nString ) := "String";
nInteger := 3; ndName( nInteger ) := "Integer"; nSequence := 4; ndName( nSequence ) := "Sequence";
nIf := 5; ndName( nIf ) := "If"; nPrtc := 6; ndName( nPrtc ) := "Prtc";
nPrts := 7; ndName( nPrts ) := "Prts"; nPrti := 8; ndName( nPrti ) := "Prti";
nWhile := 9; ndName( nWhile ) := "While"; nAssign := 10; ndName( nAssign ) := "Assign";
nNegate := 11; ndName( nNegate ) := "Negate"; nNot := 12; ndName( nNot ) := "Not";
nMultiply := 13; ndName( nMultiply ) := "Multiply"; nDivide := 14; ndName( nDivide ) := "Divide";
nMod := 15; ndName( nMod ) := "Mod"; nAdd := 16; ndName( nAdd ) := "Add";
nSubtract := 17; ndName( nSubtract ) := "Subtract"; nLess := 18; ndName( nLess ) := "Less";
nLessEqual := 19; ndName( nLessEqual ) := "LessEqual"; nGreater := 20; ndName( nGreater ) := "Greater";
nGreaterEqual := 21; ndName( nGreaterEqual ) := "GreaterEqual"; nEqual := 22; ndName( nEqual ) := "Equal";
nNotEqual := 23; ndName( nNotEqual ) := "NotEqual"; nAnd := 24; ndName( nAnd ) := "And";
nOr := 25; ndName( nOr ) := "Or";
MAX_NODE_TYPE := 25; TEXT_MAX := 4095; textNext := 0;
stList := idList := null;
for nPos := 1 until MAX_NODE_TYPE do nOp( nPos ) := -1;
nOp( nPrtc ) := oPrtc; nOp( nPrts ) := oPrts; nOp( nPrti ) := oPrti; nOp( nNegate ) := oNeg; nOp( nNot ) := oNot;
nOp( nMultiply ) := oMul; nOp( nDivide ) := oDiv; nOp( nMod ) := oMod; nOp( nAdd ) := oAdd; nOp( nSubtract ) := oSub;
nOp( nLess ) := oLt; nOp( nLessEqual ) := oLe; nOp( nGreater ) := oGt; nOp( nGreaterEqual ) := oGe; nOp( nEqual ) := oEq;
nOp( nNotEqual ) := oNe; nOp( nAnd ) := oAnd; nOp( nOr ) := oOr;
nextLocation := 0; MAX_LOCATION := 4095;
for pc := 0 until MAX_LOCATION do byteCode( pc ) := 0;
nextLabelNumber := 0; MAX_LABEL_NUMBER := 4096;
for lPos := 1 until MAX_LABEL_NUMBER do labelLocation( lPos ) := 0;
% parse the output from the syntax analyser and generate code from the parse tree %
gen( readNode );
genOp0( oHalt );
emitCode
end.
{{out}} The While Counter example
Datasize: 1 Strings: 2
"count is: "
"\n"
0 push 1
5 store [0]
10 fetch [0]
15 push 10
20 lt
21 jz (43) 65
26 push 0
31 prts
32 fetch [0]
37 prti
38 push 1
43 prts
44 fetch [0]
49 push 1
54 add
55 store [0]
60 jmp (-51) 10
65 halt
AWK
Tested with gawk 4.1.1 and mawk 1.3.4.
function error(msg) {
printf("%s\n", msg)
exit(1)
}
function bytes_to_int(bstr, i, sum) {
sum = 0
for (i=word_size-1; i>=0; i--) {
sum *= 256
sum += code[bstr+i]
}
return sum
}
function make_node(oper, left, right, value) {
node_type [next_free_node_index] = oper
node_left [next_free_node_index] = left
node_right[next_free_node_index] = right
node_value[next_free_node_index] = value
return next_free_node_index ++
}
function make_leaf(oper, n) {
return make_node(oper, 0, 0, n)
}
function emit_byte(x) {
code[next_free_code_index++] = x
}
function emit_word(x, i) {
for (i=0; i<word_size; i++) {
emit_byte(int(x)%256);
x = int(x/256)
}
}
function emit_word_at(at, n, i) {
for (i=0; i<word_size; i++) {
code[at+i] = int(n)%256
n = int(n/256)
}
}
function hole( t) {
t = next_free_code_index
emit_word(0)
return t
}
function fetch_var_offset(name, n) {
if (name in globals) {
n = globals[name]
} else {
globals[name] = globals_n
n = globals_n
globals_n += 1
}
return n
}
function fetch_string_offset(the_string, n) {
n = string_pool[the_string]
if (n == "") {
string_pool[the_string] = string_n
n = string_n
string_n += 1
}
return n
}
function code_gen(x, n, p1, p2) {
if (x == 0) {
return
} else if (node_type[x] == "nd_Ident") {
emit_byte(FETCH)
n = fetch_var_offset(node_value[x])
emit_word(n)
} else if (node_type[x] == "nd_Integer") {
emit_byte(PUSH)
emit_word(node_value[x])
} else if (node_type[x] == "nd_String") {
emit_byte(PUSH)
n = fetch_string_offset(node_value[x])
emit_word(n)
} else if (node_type[x] == "nd_Assign") {
n = fetch_var_offset(node_value[node_left[x]])
code_gen(node_right[x])
emit_byte(STORE)
emit_word(n)
} else if (node_type[x] == "nd_If") {
code_gen(node_left[x]) # expr
emit_byte(JZ) # if false, jump
p1 = hole() # make room for jump dest
code_gen(node_left[node_right[x]]) # if true statements
if (node_right[node_right[x]] != 0) {
emit_byte(JMP) # jump over else statements
p2 = hole()
}
emit_word_at(p1, next_free_code_index - p1)
if (node_right[node_right[x]] != 0) {
code_gen(node_right[node_right[x]]) # else statements
emit_word_at(p2, next_free_code_index - p2)
}
} else if (node_type[x] == "nd_While") {
p1 =next_free_code_index
code_gen(node_left[x])
emit_byte(JZ)
p2 = hole()
code_gen(node_right[x])
emit_byte(JMP) # jump back to the top
emit_word(p1 - next_free_code_index)
emit_word_at(p2, next_free_code_index - p2)
} else if (node_type[x] == "nd_Sequence") {
code_gen(node_left[x])
code_gen(node_right[x])
} else if (node_type[x] == "nd_Prtc") {
code_gen(node_left[x])
emit_byte(PRTC)
} else if (node_type[x] == "nd_Prti") {
code_gen(node_left[x])
emit_byte(PRTI)
} else if (node_type[x] == "nd_Prts") {
code_gen(node_left[x])
emit_byte(PRTS)
} else if (node_type[x] in operators) {
code_gen(node_left[x])
code_gen(node_right[x])
emit_byte(operators[node_type[x]])
} else if (node_type[x] in unary_operators) {
code_gen(node_left[x])
emit_byte(unary_operators[node_type[x]])
} else {
error("error in code generator - found '" node_type[x] "', expecting operator")
}
}
function code_finish() {
emit_byte(HALT)
}
function list_code() {
printf("Datasize: %d Strings: %d\n", globals_n, string_n)
# Make sure that arrays are sorted by value in ascending order.
PROCINFO["sorted_in"] = "@val_str_asc"
# This is a dependency on GAWK.
for (k in string_pool)
print(k)
pc = 0
while (pc < next_free_code_index) {
printf("%4d ", pc)
op = code[pc]
pc += 1
if (op == FETCH) {
x = bytes_to_int(pc)
printf("fetch [%d]\n", x);
pc += word_size
} else if (op == STORE) {
x = bytes_to_int(pc)
printf("store [%d]\n", x);
pc += word_size
} else if (op == PUSH) {
x = bytes_to_int(pc)
printf("push %d\n", x);
pc += word_size
} else if (op == ADD) { print("add")
} else if (op == SUB) { print("sub")
} else if (op == MUL) { print("mul")
} else if (op == DIV) { print("div")
} else if (op == MOD) { print("mod")
} else if (op == LT) { print("lt")
} else if (op == GT) { print("gt")
} else if (op == LE) { print("le")
} else if (op == GE) { print("ge")
} else if (op == EQ) { print("eq")
} else if (op == NE) { print("ne")
} else if (op == AND) { print("and")
} else if (op == OR) { print("or")
} else if (op == NEG) { print("neg")
} else if (op == NOT) { print("not")
} else if (op == JMP) {
x = bytes_to_int(pc)
printf("jmp (%d) %d\n", x, pc + x);
pc += word_size
} else if (op == JZ) {
x = bytes_to_int(pc)
printf("jz (%d) %d\n", x, pc + x);
pc += word_size
} else if (op == PRTC) { print("prtc")
} else if (op == PRTI) { print("prti")
} else if (op == PRTS) { print("prts")
} else if (op == HALT) { print("halt")
} else { error("list_code: Unknown opcode '" op "'")
}
} # while pc
}
function load_ast( line, line_list, text, n, node_type, value, left, right) {
getline line
n=split(line, line_list)
text = line_list[1]
if (text == ";")
return 0
node_type = all_syms[text]
if (n > 1) {
value = line_list[2]
for (i=3;i<=n;i++)
value = value " " line_list[i]
if (value ~ /^[0-9]+$/)
value = int(value)
return make_leaf(node_type, value)
}
left = load_ast()
right = load_ast()
return make_node(node_type, left, right)
}
BEGIN {
all_syms["Identifier" ] = "nd_Ident"
all_syms["String" ] = "nd_String"
all_syms["Integer" ] = "nd_Integer"
all_syms["Sequence" ] = "nd_Sequence"
all_syms["If" ] = "nd_If"
all_syms["Prtc" ] = "nd_Prtc"
all_syms["Prts" ] = "nd_Prts"
all_syms["Prti" ] = "nd_Prti"
all_syms["While" ] = "nd_While"
all_syms["Assign" ] = "nd_Assign"
all_syms["Negate" ] = "nd_Negate"
all_syms["Not" ] = "nd_Not"
all_syms["Multiply" ] = "nd_Mul"
all_syms["Divide" ] = "nd_Div"
all_syms["Mod" ] = "nd_Mod"
all_syms["Add" ] = "nd_Add"
all_syms["Subtract" ] = "nd_Sub"
all_syms["Less" ] = "nd_Lss"
all_syms["LessEqual" ] = "nd_Leq"
all_syms["Greater" ] = "nd_Gtr"
all_syms["GreaterEqual"] = "nd_Geq"
all_syms["Equal" ] = "nd_Eql"
all_syms["NotEqual" ] = "nd_Neq"
all_syms["And" ] = "nd_And"
all_syms["Or" ] = "nd_Or"
FETCH=1; STORE=2; PUSH=3; ADD=4; SUB=5; MUL=6;
DIV=7; MOD=8; LT=9; GT=10; LE=11; GE=12;
EQ=13; NE=14; AND=15; OR=16; NEG=17; NOT=18;
JMP=19; JZ=20; PRTC=21; PRTS=22; PRTI=23; HALT=24;
operators["nd_Lss"] = LT
operators["nd_Gtr"] = GT
operators["nd_Leq"] = LE
operators["nd_Geq"] = GE
operators["nd_Eql"] = EQ
operators["nd_Neq"] = NE
operators["nd_And"] = AND
operators["nd_Or" ] = OR
operators["nd_Sub"] = SUB
operators["nd_Add"] = ADD
operators["nd_Div"] = DIV
operators["nd_Mul"] = MUL
operators["nd_Mod"] = MOD
unary_operators["nd_Negate"] = NEG
unary_operators["nd_Not" ] = NOT
next_free_node_index = 1
next_free_code_index = 0
globals_n = 0
string_n = 0
word_size = 4
input_file = "-"
if (ARGC > 1)
input_file = ARGV[1]
n = load_ast()
code_gen(n)
code_finish()
list_code()
}
{{out|case=count}}
Datasize: 1 Strings: 2
"count is: "
"\n"
0 push 1
5 store [0]
10 fetch [0]
15 push 10
20 lt
21 jz (43) 65
26 push 0
31 prts
32 fetch [0]
37 prti
38 push 1
43 prts
44 fetch [0]
49 push 1
54 add
55 store [0]
60 jmp (-51) 10
65 halt
C
Tested with gcc 4.81 and later, compiles warning free with -Wall -Wextra
#include <iostream>
#include <stdio.h>
#include <string.h>
#include <stdarg.h>
#include <stdint.h>
#include <ctype.h>
typedef unsigned char uchar;
typedef enum {
nd_Ident, nd_String, nd_Integer, nd_Sequence, nd_If, nd_Prtc, nd_Prts, nd_Prti, nd_While,
nd_Assign, nd_Negate, nd_Not, nd_Mul, nd_Div, nd_Mod, nd_Add, nd_Sub, nd_Lss, nd_Leq,
nd_Gtr, nd_Geq, nd_Eql, nd_Neq, nd_And, nd_Or
} NodeType;
typedef enum { FETCH, STORE, PUSH, ADD, SUB, MUL, DIV, MOD, LT, GT, LE, GE, EQ, NE, AND,
OR, NEG, NOT, JMP, JZ, PRTC, PRTS, PRTI, HALT
} Code_t;
typedef uchar code;
typedef struct Tree {
NodeType node_type;
struct Tree *left;
struct Tree *right;
char *value;
} Tree;
#define da_dim(name, type) type *name = NULL; \
int _qy_ ## name ## _p = 0; \
int _qy_ ## name ## _max = 0
#define da_redim(name) do {if (_qy_ ## name ## _p >= _qy_ ## name ## _max) \
name = realloc(name, (_qy_ ## name ## _max += 32) * sizeof(name[0]));} while (0)
#define da_rewind(name) _qy_ ## name ## _p = 0
#define da_append(name, x) do {da_redim(name); name[_qy_ ## name ## _p++] = x;} while (0)
#define da_len(name) _qy_ ## name ## _p
#define da_add(name) do {da_redim(name); _qy_ ## name ## _p++;} while (0)
FILE *source_fp, *dest_fp;
static int here;
da_dim(object, code);
da_dim(globals, const char *);
da_dim(string_pool, const char *);
// dependency: Ordered by NodeType, must remain in same order as NodeType enum
struct {
char *enum_text;
NodeType node_type;
Code_t opcode;
} atr[] = {
{"Identifier" , nd_Ident, -1 },
{"String" , nd_String, -1 },
{"Integer" , nd_Integer, -1 },
{"Sequence" , nd_Sequence, -1 },
{"If" , nd_If, -1 },
{"Prtc" , nd_Prtc, -1 },
{"Prts" , nd_Prts, -1 },
{"Prti" , nd_Prti, -1 },
{"While" , nd_While, -1 },
{"Assign" , nd_Assign, -1 },
{"Negate" , nd_Negate, NEG},
{"Not" , nd_Not, NOT},
{"Multiply" , nd_Mul, MUL},
{"Divide" , nd_Div, DIV},
{"Mod" , nd_Mod, MOD},
{"Add" , nd_Add, ADD},
{"Subtract" , nd_Sub, SUB},
{"Less" , nd_Lss, LT },
{"LessEqual" , nd_Leq, LE },
{"Greater" , nd_Gtr, GT },
{"GreaterEqual", nd_Geq, GE },
{"Equal" , nd_Eql, EQ },
{"NotEqual" , nd_Neq, NE },
{"And" , nd_And, AND},
{"Or" , nd_Or, OR },
};
void error(const char *fmt, ... ) {
va_list ap;
char buf[1000];
va_start(ap, fmt);
vsprintf(buf, fmt, ap);
va_end(ap);
printf("error: %s\n", buf);
exit(1);
}
Code_t type_to_op(NodeType type) {
return atr[type].opcode;
}
Tree *make_node(NodeType node_type, Tree *left, Tree *right) {
Tree *t = calloc(sizeof(Tree), 1);
t->node_type = node_type;
t->left = left;
t->right = right;
return t;
}
Tree *make_leaf(NodeType node_type, char *value) {
Tree *t = calloc(sizeof(Tree), 1);
t->node_type = node_type;
t->value = strdup(value);
return t;
}
/*** Code generator ***/
void emit_byte(int c) {
da_append(object, (uchar)c);
++here;
}
void emit_int(int32_t n) {
union {
int32_t n;
unsigned char c[sizeof(int32_t)];
} x;
x.n = n;
for (size_t i = 0; i < sizeof(x.n); ++i) {
emit_byte(x.c[i]);
}
}
int hole() {
int t = here;
emit_int(0);
return t;
}
void fix(int src, int dst) {
*(int32_t *)(object + src) = dst-src;
}
int fetch_var_offset(const char *id) {
for (int i = 0; i < da_len(globals); ++i) {
if (strcmp(id, globals[i]) == 0)
return i;
}
da_add(globals);
int n = da_len(globals) - 1;
globals[n] = strdup(id);
return n;
}
int fetch_string_offset(const char *st) {
for (int i = 0; i < da_len(string_pool); ++i) {
if (strcmp(st, string_pool[i]) == 0)
return i;
}
da_add(string_pool);
int n = da_len(string_pool) - 1;
string_pool[n] = strdup(st);
return n;
}
void code_gen(Tree *x) {
int p1, p2, n;
if (x == NULL) return;
switch (x->node_type) {
case nd_Ident:
emit_byte(FETCH);
n = fetch_var_offset(x->value);
emit_int(n);
break;
case nd_Integer:
emit_byte(PUSH);
emit_int(atoi(x->value));
break;
case nd_String:
emit_byte(PUSH);
n = fetch_string_offset(x->value);
emit_int(n);
break;
case nd_Assign:
n = fetch_var_offset(x->left->value);
code_gen(x->right);
emit_byte(STORE);
emit_int(n);
break;
case nd_If:
code_gen(x->left); // if expr
emit_byte(JZ); // if false, jump
p1 = hole(); // make room for jump dest
code_gen(x->right->left); // if true statements
if (x->right->right != NULL) {
emit_byte(JMP);
p2 = hole();
}
fix(p1, here);
if (x->right->right != NULL) {
code_gen(x->right->right);
fix(p2, here);
}
break;
case nd_While:
p1 = here;
code_gen(x->left); // while expr
emit_byte(JZ); // if false, jump
p2 = hole(); // make room for jump dest
code_gen(x->right); // statements
emit_byte(JMP); // back to the top
fix(hole(), p1); // plug the top
fix(p2, here); // plug the 'if false, jump'
break;
case nd_Sequence:
code_gen(x->left);
code_gen(x->right);
break;
case nd_Prtc:
code_gen(x->left);
emit_byte(PRTC);
break;
case nd_Prti:
code_gen(x->left);
emit_byte(PRTI);
break;
case nd_Prts:
code_gen(x->left);
emit_byte(PRTS);
break;
case nd_Lss: case nd_Gtr: case nd_Leq: case nd_Geq: case nd_Eql: case nd_Neq:
case nd_And: case nd_Or: case nd_Sub: case nd_Add: case nd_Div: case nd_Mul:
case nd_Mod:
code_gen(x->left);
code_gen(x->right);
emit_byte(type_to_op(x->node_type));
break;
case nd_Negate: case nd_Not:
code_gen(x->left);
emit_byte(type_to_op(x->node_type));
break;
default:
error("error in code generator - found %d, expecting operator\n", x->node_type);
}
}
void code_finish() {
emit_byte(HALT);
}
void list_code() {
fprintf(dest_fp, "Datasize: %d Strings: %d\n", da_len(globals), da_len(string_pool));
for (int i = 0; i < da_len(string_pool); ++i)
fprintf(dest_fp, "%s\n", string_pool[i]);
code *pc = object;
again: fprintf(dest_fp, "%5d ", (int)(pc - object));
switch (*pc++) {
case FETCH: fprintf(dest_fp, "fetch [%d]\n", *(int32_t *)pc);
pc += sizeof(int32_t); goto again;
case STORE: fprintf(dest_fp, "store [%d]\n", *(int32_t *)pc);
pc += sizeof(int32_t); goto again;
case PUSH : fprintf(dest_fp, "push %d\n", *(int32_t *)pc);
pc += sizeof(int32_t); goto again;
case ADD : fprintf(dest_fp, "add\n"); goto again;
case SUB : fprintf(dest_fp, "sub\n"); goto again;
case MUL : fprintf(dest_fp, "mul\n"); goto again;
case DIV : fprintf(dest_fp, "div\n"); goto again;
case MOD : fprintf(dest_fp, "mod\n"); goto again;
case LT : fprintf(dest_fp, "lt\n"); goto again;
case GT : fprintf(dest_fp, "gt\n"); goto again;
case LE : fprintf(dest_fp, "le\n"); goto again;
case GE : fprintf(dest_fp, "ge\n"); goto again;
case EQ : fprintf(dest_fp, "eq\n"); goto again;
case NE : fprintf(dest_fp, "ne\n"); goto again;
case AND : fprintf(dest_fp, "and\n"); goto again;
case OR : fprintf(dest_fp, "or\n"); goto again;
case NOT : fprintf(dest_fp, "not\n"); goto again;
case NEG : fprintf(dest_fp, "neg\n"); goto again;
case JMP : fprintf(dest_fp, "jmp (%d) %d\n",
*(int32_t *)pc, (int32_t)(pc + *(int32_t *)pc - object));
pc += sizeof(int32_t); goto again;
case JZ : fprintf(dest_fp, "jz (%d) %d\n",
*(int32_t *)pc, (int32_t)(pc + *(int32_t *)pc - object));
pc += sizeof(int32_t); goto again;
case PRTC : fprintf(dest_fp, "prtc\n"); goto again;
case PRTI : fprintf(dest_fp, "prti\n"); goto again;
case PRTS : fprintf(dest_fp, "prts\n"); goto again;
case HALT : fprintf(dest_fp, "halt\n"); break;
default:error("listcode:Unknown opcode %d\n", *(pc - 1));
}
}
void init_io(FILE **fp, FILE *std, const char mode[], const char fn[]) {
if (fn[0] == '\0')
*fp = std;
else if ((*fp = fopen(fn, mode)) == NULL)
error(0, 0, "Can't open %s\n", fn);
}
NodeType get_enum_value(const char name[]) {
for (size_t i = 0; i < sizeof(atr) / sizeof(atr[0]); i++) {
if (strcmp(atr[i].enum_text, name) == 0) {
return atr[i].node_type;
}
}
error("Unknown token %s\n", name);
return -1;
}
char *read_line(int *len) {
static char *text = NULL;
static int textmax = 0;
for (*len = 0; ; (*len)++) {
int ch = fgetc(source_fp);
if (ch == EOF || ch == '\n') {
if (*len == 0)
return NULL;
break;
}
if (*len + 1 >= textmax) {
textmax = (textmax == 0 ? 128 : textmax * 2);
text = realloc(text, textmax);
}
text[*len] = ch;
}
text[*len] = '\0';
return text;
}
char *rtrim(char *text, int *len) { // remove trailing spaces
for (; *len > 0 && isspace(text[*len - 1]); --(*len))
;
text[*len] = '\0';
return text;
}
Tree *load_ast() {
int len;
char *yytext = read_line(&len);
yytext = rtrim(yytext, &len);
// get first token
char *tok = strtok(yytext, " ");
if (tok[0] == ';') {
return NULL;
}
NodeType node_type = get_enum_value(tok);
// if there is extra data, get it
char *p = tok + strlen(tok);
if (p != &yytext[len]) {
for (++p; isspace(*p); ++p)
;
return make_leaf(node_type, p);
}
Tree *left = load_ast();
Tree *right = load_ast();
return make_node(node_type, left, right);
}
int main(int argc, char *argv[]) {
init_io(&source_fp, stdin, "r", argc > 1 ? argv[1] : "");
init_io(&dest_fp, stdout, "wb", argc > 2 ? argv[2] : "");
code_gen(load_ast());
code_finish();
list_code();
return 0;
}
{{out|case=While counter example}}
Datasize: 1 Strings: 2
"count is: "
"\n"
0 push 1
5 store [0]
10 fetch [0]
15 push 10
20 lt
21 jz (43) 65
26 push 0
31 prts
32 fetch [0]
37 prti
38 push 1
43 prts
44 fetch [0]
49 push 1
54 add
55 store [0]
60 jmp (-51) 10
65 halt
COBOL
Code by Steve Williams. Tested with GnuCOBOL 2.2.
SOURCE FORMAT IS FREE
identification division.
*> this code is dedicated to the public domain
*> (GnuCOBOL) 2.3-dev.0
program-id. generator.
environment division.
configuration section.
repository. function all intrinsic.
data division.
working-storage section.
01 program-name pic x(32) value spaces global.
01 input-name pic x(32) value spaces global.
01 input-status pic xx global.
01 ast-record global.
03 ast-type pic x(14).
03 ast-value pic x(48).
03 filler redefines ast-value.
05 asl-left pic 999.
05 asl-right pic 999.
01 error-record pic x(64) value spaces global.
01 loadstack global.
03 l pic 99 value 0.
03 l-lim pic 99 value 64.
03 load-entry occurs 64.
05 l-node pic x(14).
05 l-left pic 999.
05 l-right pic 999.
05 l-link pic 999.
01 abstract-syntax-tree global.
03 t pic 999 value 0.
03 t1 pic 999.
03 t-lim pic 999 value 998.
03 filler occurs 998.
05 p1 pic 999.
05 p2 pic 999.
05 p3 pic 999.
05 n1 pic 999.
05 leaf.
07 leaf-type pic x(14).
07 leaf-value pic x(48).
05 node redefines leaf.
07 node-type pic x(14).
07 node-left pic 999.
07 node-right pic 999.
01 opcodes global.
03 opFETCH pic x value x'00'.
03 opSTORE pic x value x'01'.
03 opPUSH pic x value x'02'.
03 opADD pic x value x'03'.
03 opSUB pic x value x'04'.
03 opMUL pic x value x'05'.
03 opDIV pic x value x'06'.
03 opMOD pic x value x'07'.
03 opLT pic x value x'08'.
03 opGT pic x value x'09'.
03 opLE pic x value x'0A'.
03 opGE pic x value x'0B'.
03 opEQ pic x value x'0C'.
03 opNE pic x value x'0D'.
03 opAND pic x value x'0E'.
03 opOR pic x value x'0F'.
03 opNEG pic x value x'10'.
03 opNOT pic x value x'11'.
03 opJMP pic x value x'13'.
03 opJZ pic x value x'14'.
03 opPRTC pic x value x'15'.
03 opPRTS pic x value x'16'.
03 opPRTI pic x value x'17'.
03 opHALT pic x value x'18'.
01 variables global.
03 v pic 99.
03 v-max pic 99 value 0.
03 v-lim pic 99 value 16.
03 variable-entry occurs 16 pic x(48).
01 strings global.
03 s pic 99.
03 s-max pic 99 value 0.
03 s-lim pic 99 value 16.
03 string-entry occurs 16 pic x(48).
01 generated-code global.
03 c pic 999 value 1.
03 c1 pic 999.
03 c-lim pic 999 value 512.
03 kode pic x(512).
procedure division chaining program-name.
start-generator.
call 'loadast'
if program-name <> spaces
call 'readinput' *> close input-file
end-if
>>d perform print-ast
call 'codegen' using t
call 'emitbyte' using opHALT
>>d call 'showhex' using kode c
call 'listcode'
stop run
.
print-ast.
call 'printast' using t
display 'ast:' upon syserr
display 't=' t
perform varying t1 from 1 by 1 until t1 > t
if leaf-type(t1) = 'Identifier' or 'Integer' or 'String'
display t1 space trim(leaf-type(t1)) space trim(leaf-value(t1)) upon syserr
else
display t1 space node-left(t1) space node-right(t1) space trim(node-type(t1))
upon syserr
end-if
end-perform
.
identification division.
program-id. codegen common recursive.
data division.
working-storage section.
01 r pic ---9.
linkage section.
01 n pic 999.
procedure division using n.
start-codegen.
if n = 0
exit program
end-if
>>d display 'at 'c ' node=' space n space node-type(n) upon syserr
evaluate node-type(n)
when 'Identifier'
call 'emitbyte' using opFetch
call 'variableoffset' using leaf-value(n)
call 'emitword' using v '0'
when 'Integer'
call 'emitbyte' using opPUSH
call 'emitword' using leaf-value(n) '0'
when 'String'
call 'emitbyte' using opPUSH
call 'stringoffset' using leaf-value(n)
call 'emitword' using s '0'
when 'Assign'
call 'codegen' using node-right(n)
call 'emitbyte' using opSTORE
move node-left(n) to n1(n)
call 'variableoffset' using leaf-value(n1(n))
call 'emitword' using v '0'
when 'If'
call 'codegen' using node-left(n) *> conditional expr
call 'emitbyte' using opJZ *> jump to false path or exit
move c to p1(n)
call 'emitword' using '0' '0'
move node-right(n) to n1(n) *> true path
call 'codegen' using node-left(n1(n))
if node-right(n1(n)) <> 0 *> there is a false path
call 'emitbyte' using opJMP *> jump past false path
move c to p2(n)
call 'emitword' using '0' '0'
compute r = c - p1(n) *> fill in jump to false path
call 'emitword' using r p1(n)
call 'codegen' using node-right(n1(n)) *> false path
compute r = c - p2(n) *> fill in jump to exit
call 'emitword' using r p2(n)
else
compute r = c - p1(n)
call 'emitword' using r p1(n) *> fill in jump to exit
end-if
when 'While'
move c to p3(n) *> save address of while start
call 'codegen' using node-left(n) *> conditional expr
call 'emitbyte' using opJZ *> jump to exit
move c to p2(n)
call 'emitword' using '0' '0'
call 'codegen' using node-right(n) *> while body
call 'emitbyte' using opJMP *> jump to while start
compute r = p3(n) - c
call 'emitword' using r '0'
compute r = c - p2(n) *> fill in jump to exit
call 'emitword' using r p2(n)
when 'Sequence'
call 'codegen' using node-left(n)
call 'codegen' using node-right(n)
when 'Prtc'
call 'codegen' using node-left(n)
call 'emitbyte' using opPRTC
when 'Prti'
call 'codegen' using node-left(n)
call 'emitbyte' using opPRTI
when 'Prts'
call 'codegen' using node-left(n)
call 'emitbyte' using opPRTS
when 'Less'
call 'codegen' using node-left(n)
call 'codegen' using node-right(n)
call 'emitbyte' using opLT
when 'Greater'
call 'codegen' using node-left(n)
call 'codegen' using node-right(n)
call 'emitbyte' using opGT
when 'LessEqual'
call 'codegen' using node-left(n)
call 'codegen' using node-right(n)
call 'emitbyte' using opLE
when 'GreaterEqual'
call 'codegen' using node-left(n)
call 'codegen' using node-right(n)
call 'emitbyte' using opGE
when 'Equal'
call 'codegen' using node-left(n)
call 'codegen' using node-right(n)
call 'emitbyte' using opEQ
when 'NotEqual'
call 'codegen' using node-left(n)
call 'codegen' using node-right(n)
call 'emitbyte' using opNE
when 'And'
call 'codegen' using node-left(n)
call 'codegen' using node-right(n)
call 'emitbyte' using opAND
when 'Or'
call 'codegen' using node-left(n)
call 'codegen' using node-right(n)
call 'emitbyte' using opOR
when 'Subtract'
call 'codegen' using node-left(n)
call 'codegen' using node-right(n)
call 'emitbyte' using opSUB
when 'Add'
call 'codegen' using node-left(n)
call 'codegen' using node-right(n)
call 'emitbyte' using opADD
when 'Divide'
call 'codegen' using node-left(n)
call 'codegen' using node-right(n)
call 'emitbyte' using opDIV
when 'Multiply'
call 'codegen' using node-left(n)
call 'codegen' using node-right(n)
call 'emitbyte' using opMUL
when 'Mod'
call 'codegen' using node-left(n)
call 'codegen' using node-right(n)
call 'emitbyte' using opMOD
when 'Negate'
call 'codegen' using node-left(n)
call 'emitbyte' using opNEG
when 'Not'
call 'codegen' using node-left(n)
call 'emitbyte' using opNOT
when other
string 'in generator unknown node type: ' node-type(n) into error-record
call 'reporterror'
end-evaluate
.
end program codegen.
identification division.
program-id. variableoffset common.
data division.
linkage section.
01 variable-value pic x(48).
procedure division using variable-value.
start-variableoffset.
perform varying v from 1 by 1
until v > v-max
or variable-entry(v) = variable-value
continue
end-perform
if v > v-lim
string 'in generator variable offset v exceeds ' v-lim into error-record
call 'reporterror'
end-if
if v > v-max
move v to v-max
move variable-value to variable-entry(v)
end-if
.
end program variableoffset.
identification division.
program-id. stringoffset common.
data division.
linkage section.
01 string-value pic x(48).
procedure division using string-value.
start-stringoffset.
perform varying s from 1 by 1
until s > s-max
or string-entry(s) = string-value
continue
end-perform
if s > s-lim
string ' generator stringoffset s exceeds ' s-lim into error-record
call 'reporterror'
end-if
if s > s-max
move s to s-max
move string-value to string-entry(s)
end-if
subtract 1 from s *> convert index to offset
.
end program stringoffset.
identification division.
program-id. emitbyte common.
data division.
linkage section.
01 opcode pic x.
procedure division using opcode.
start-emitbyte.
if c >= c-lim
string 'in generator emitbyte c exceeds ' c-lim into error-record
call 'reporterror'
end-if
move opcode to kode(c:1)
add 1 to c
.
end program emitbyte.
identification division.
program-id. emitword common.
data division.
working-storage section.
01 word-x.
03 word usage binary-int.
01 loc pic 999.
linkage section.
01 word-value any length.
01 loc-value any length.
procedure division using word-value loc-value.
start-emitword.
if c + length(word) > c-lim
string 'in generator emitword exceeds ' c-lim into error-record
call 'reporterror'
end-if
move numval(word-value) to word
move numval(loc-value) to loc
if loc = 0
move word-x to kode(c:length(word))
add length(word) to c
else
move word-x to kode(loc:length(word))
end-if
.
end program emitword.
identification division.
program-id. listcode common.
data division.
working-storage section.
01 word-x.
03 word usage binary-int.
01 address-display pic ---9.
01 address-absolute pic zzz9.
01 data-display pic -(9)9.
01 v-display pic z9.
01 s-display pic z9.
01 c-display pic zzz9.
procedure division.
start-listcode.
move v-max to v-display
move s-max to s-display
display 'Datasize: ' trim(v-display) space 'Strings: ' trim(s-display)
perform varying s from 1 by 1
until s > s-max
display string-entry(s)
end-perform
move 1 to c1
perform until c1 >= c
compute c-display = c1 - 1
display c-display space with no advancing
evaluate kode(c1:1)
when opFETCH
add 1 to c1
move kode(c1:4) to word-x
compute address-display = word - 1
display 'fetch [' trim(address-display) ']'
add 3 to c1
when opSTORE
add 1 to c1
move kode(c1:4) to word-x
compute address-display = word - 1
display 'store [' trim(address-display) ']'
add 3 to c1
when opPUSH
add 1 to c1
move kode(c1:4) to word-x
move word to data-display
display 'push ' trim(data-display)
add 3 to c1
when opADD display 'add'
when opSUB display 'sub'
when opMUL display 'mul'
when opDIV display 'div'
when opMOD display 'mod'
when opLT display 'lt'
when opGT display 'gt'
when opLE display 'le'
when opGE display 'ge'
when opEQ display 'eq'
when opNE display 'ne'
when opAND display 'and'
when opOR display 'or'
when opNEG display 'neg'
when opNOT display 'not'
when opJMP
move kode(c1 + 1:length(word)) to word-x
move word to address-display
compute address-absolute = c1 + word
display 'jmp (' trim(address-display) ') ' trim(address-absolute)
add length(word) to c1
when opJZ
move kode(c1 + 1:length(word)) to word-x
move word to address-display
compute address-absolute = c1 + word
display 'jz (' trim(address-display) ') ' trim(address-absolute)
add length(word) to c1
when opPRTC display 'prtc'
when opPRTI display 'prti'
when opPRTS display 'prts'
when opHALT display 'halt'
when other
string 'in generator unknown opcode ' kode(c1:1) into error-record
call 'reporterror'
end-evaluate
add 1 to c1
end-perform
.
end program listcode.
identification division.
program-id. loadast common recursive.
procedure division.
start-loadast.
if l >= l-lim
string 'in generator loadast l exceeds ' l-lim into error-record
call 'reporterror'
end-if
add 1 to l
call 'readinput'
evaluate true
when ast-record = ';'
when input-status = '10'
move 0 to return-code
when ast-type = 'Identifier'
when ast-type = 'Integer'
when ast-type = 'String'
call 'makeleaf' using ast-type ast-value
move t to return-code
when ast-type = 'Sequence'
move ast-type to l-node(l)
call 'loadast'
move return-code to l-left(l)
call 'loadast'
move t to l-right(l)
call 'makenode' using l-node(l) l-left(l) l-right(l)
move t to return-code
when other
move ast-type to l-node(l)
call 'loadast'
move return-code to l-left(l)
call 'loadast'
move return-code to l-right(l)
call 'makenode' using l-node(l) l-left(l) l-right(l)
move t to return-code
end-evaluate
subtract 1 from l
.
end program loadast.
identification division.
program-id. printast common recursive.
data division.
linkage section.
01 n pic 999.
procedure division using n.
start-printast.
if n = 0
display ';' upon syserr
exit program
end-if
display leaf-type(n) upon syserr
evaluate leaf-type(n)
when 'Identifier'
when 'Integer'
when 'String'
display leaf-type(n) space trim(leaf-value(n)) upon syserr
when other
display node-type(n) upon syserr
call 'printast' using node-left(n)
call 'printast' using node-right(n)
end-evaluate
.
end program printast.
identification division.
program-id. makenode common.
data division.
linkage section.
01 parm-type any length.
01 parm-l-left pic 999.
01 parm-l-right pic 999.
procedure division using parm-type parm-l-left parm-l-right.
start-makenode.
if t >= t-lim
string 'in generator makenode t exceeds ' t-lim into error-record
call 'reporterror'
end-if
add 1 to t
move parm-type to node-type(t)
move parm-l-left to node-left(t)
move parm-l-right to node-right(t)
.
end program makenode.
identification division.
program-id. makeleaf common.
data division.
linkage section.
01 parm-type any length.
01 parm-value pic x(48).
procedure division using parm-type parm-value.
start-makeleaf.
add 1 to t
if t >= t-lim
string 'in generator makeleaf t exceeds ' t-lim into error-record
call 'reporterror'
end-if
move parm-type to leaf-type(t)
move parm-value to leaf-value(t)
.
end program makeleaf.
identification division.
program-id. readinput common.
environment division.
input-output section.
file-control.
select input-file assign using input-name
status is input-status
organization is line sequential.
data division.
file section.
fd input-file.
01 input-record pic x(64).
procedure division.
start-readinput.
if program-name = spaces
move '00' to input-status
accept ast-record on exception move '10' to input-status end-accept
exit program
end-if
if input-name = spaces
string program-name delimited by space '.ast' into input-name
open input input-file
if input-status = '35'
string 'in generator ' trim(input-name) ' not found' into error-record
call 'reporterror'
end-if
end-if
read input-file into ast-record
evaluate input-status
when '00'
continue
when '10'
close input-file
when other
string 'in generator ' trim(input-name) ' unexpected input-status: ' input-status
into error-record
call 'reporterror'
end-evaluate
.
end program readinput.
program-id. reporterror common.
procedure division.
start-reporterror.
report-error.
display error-record upon syserr
stop run with error status -1
.
end program reporterror.
identification division.
program-id. showhex common.
data division.
working-storage section.
01 hex.
03 filler pic x(32) value '000102030405060708090A0B0C0D0E0F'.
03 filler pic x(32) value '101112131415161718191A1B1C1D1E1F'.
03 filler pic x(32) value '202122232425262728292A2B2C2D2E2F'.
03 filler pic x(32) value '303132333435363738393A3B3C3D3E3F'.
03 filler pic x(32) value '404142434445464748494A4B4C4D4E4F'.
03 filler pic x(32) value '505152535455565758595A5B5C5D5E5F'.
03 filler pic x(32) value '606162636465666768696A6B6C6D6E6F'.
03 filler pic x(32) value '707172737475767778797A7B7C7D7E7F'.
03 filler pic x(32) value '808182838485868788898A8B8C8D8E8F'.
03 filler pic x(32) value '909192939495969798999A9B9C9D9E9F'.
03 filler pic x(32) value 'A0A1A2A3A4A5A6A7A8A9AAABACADAEAF'.
03 filler pic x(32) value 'B0B1B2B3B4B5B6B7B8B9BABBBCBDBEBF'.
03 filler pic x(32) value 'C0C1C2C3C4C5C6C7C8C9CACBCCCDCECF'.
03 filler pic x(32) value 'D0D1D2D3D4D5D6D7D8D9DADBDCDDDEDF'.
03 filler pic x(32) value 'E0E1E2E3E4E5E6E7E8E9EAEBECEDEEEF'.
03 filler pic x(32) value 'F0F1F2F3F4F5F6F7F8F9FAFBFCFDFEFF'.
01 cdx pic 9999.
01 bdx pic 999.
01 byte-count pic 9.
01 bytes-per-word pic 9 value 4.
01 word-count pic 9.
01 words-per-line pic 9 value 8.
linkage section.
01 data-field any length.
01 length-data-field pic 999.
procedure division using
by reference data-field
by reference length-data-field.
start-showhex.
move 1 to byte-count
move 1 to word-count
perform varying cdx from 1 by 1
until cdx > length-data-field
compute bdx = 2 * ord(data-field(cdx:1)) - 1 end-compute
display hex(bdx:2) with no advancing upon syserr
add 1 to byte-count end-add
if byte-count > bytes-per-word
display ' ' with no advancing upon syserr
move 1 to byte-count
add 1 to word-count end-add
end-if
if word-count > words-per-line
display ' ' upon syserr
move 1 to word-count
end-if
end-perform
if word-count <> 1
or byte-count <> 1
display ' ' upon syserr
end-if
display ' ' upon syserr
goback
.
end program showhex.
end program generator.
{{out|case=Count}}
prompt$ ./lexer <testcases/Count | ./parser | ./generator
Datasize: 1 Strings: 2
"count is: "
"\n"
0 push 1
5 store [0]
10 fetch [0]
15 push 10
20 lt
21 jz (43) 65
26 push 0
31 prts
32 fetch [0]
37 prti
38 push 1
43 prts
44 fetch [0]
49 push 1
54 add
55 store [0]
60 jmp (-51) 10
65 halt
Forth
Tested with Gforth 0.7.3
CREATE BUF 0 ,
: PEEK BUF @ 0= IF KEY BUF ! THEN BUF @ ;
: GETC PEEK 0 BUF ! ;
: SPACE? DUP BL = SWAP 9 14 WITHIN OR ;
: >SPACE BEGIN PEEK SPACE? WHILE GETC DROP REPEAT ;
: DIGIT? 48 58 WITHIN ;
: >Integer >SPACE 0
BEGIN PEEK DIGIT?
WHILE GETC [CHAR] 0 - SWAP 10 * + REPEAT ;
: SKIP ( xt --)
BEGIN PEEK OVER EXECUTE WHILE GETC DROP REPEAT DROP ;
: WORD ( xt -- c-addr) DUP >R SKIP PAD 1+
BEGIN PEEK R@ EXECUTE INVERT
WHILE GETC OVER C! CHAR+
REPEAT R> SKIP PAD TUCK - 1- PAD C! ;
: INTERN ( c-addr -- c-addr)
HERE TUCK OVER C@ CHAR+ DUP ALLOT CMOVE ;
: "? [CHAR] " = ;
: "TYPE" [CHAR] " EMIT TYPE [CHAR] " EMIT ;
: . 0 .R ;
: 3@ ( addr -- w3 w2 w1)
[ 2 CELLS ]L + DUP @ SWAP CELL - DUP @ SWAP CELL - @ ;
CREATE BUF' 12 ALLOT
: PREPEND ( c-addr c -- c-addr) BUF' 1+ C!
COUNT 10 MIN DUP 1+ BUF' C! BUF' 2 + SWAP CMOVE BUF' ;
: >NODE ( c-addr -- n) [CHAR] $ PREPEND FIND
IF EXECUTE ELSE ." unrecognized node " COUNT TYPE CR THEN ;
: NODE ( n left right -- addr) HERE >R , , , R> ;
: CONS ( a b l -- l) HERE >R , , , R> ;
: FIRST ( l -- a) [ 2 CELLS ]L + @ ;
: SECOND ( l -- b) CELL+ @ ;
: C=? ( c-addr1 c-addr2 -- t|f) COUNT ROT COUNT COMPARE 0= ;
: LOOKUP ( c-addr l -- n t | c-addr f)
BEGIN DUP WHILE OVER OVER FIRST C=?
IF NIP SECOND TRUE EXIT THEN @
REPEAT DROP FALSE ;
CREATE GLOBALS 0 , CREATE STRINGS 0 ,
: DEPTH ( pool -- n) DUP IF SECOND 1+ THEN ;
: FISH ( c-addr pool -- n pool') TUCK LOOKUP IF SWAP
ELSE INTERN OVER DEPTH ROT OVER >R CONS R> SWAP THEN ;
: >Identifier ['] SPACE? WORD GLOBALS @ FISH GLOBALS ! ;
: >String ['] "? WORD STRINGS @ FISH STRINGS ! ;
: >; 0 ;
: HANDLER [CHAR] @ PREPEND FIND DROP ;
: READER ( c-addr -- xt t | f)
[CHAR] > PREPEND FIND DUP 0= IF NIP THEN ;
DEFER GETAST
: READ ( c-addr -- right left) READER
IF EXECUTE 0 ELSE GETAST GETAST THEN SWAP ;
: (GETAST) ['] SPACE? WORD DUP HANDLER >R READ R> NODE ;
' (GETAST) IS GETAST
CREATE PC 0 ,
: i32! ( n addr --)
OVER $FF AND OVER C! 1+
OVER 8 RSHIFT $FF AND OVER C! 1+
OVER 16 RSHIFT $FF AND OVER C! 1+
OVER 24 RSHIFT $FF AND OVER C! DROP DROP ;
: i32, ( n --) HERE i32! 4 ALLOT 4 PC +! ;
: i8, ( c --) C, 1 PC +! ;
: i8@+ DUP 1+ SWAP C@ 1 PC +! ;
: i32@+ ( addr -- addr+4 n)
i8@+ >R i8@+ 8 LSHIFT R> OR >R
i8@+ 16 LSHIFT R> OR >R i8@+ 24 LSHIFT R> OR ;
CREATE #OPS 0 ,
: OP: CREATE #OPS @ , 1 #OPS +! DOES> @ ;
OP: fetch OP: store OP: push OP: jmp OP: jz
OP: prtc OP: prti OP: prts OP: neg OP: not
OP: add OP: sub OP: mul OP: div OP: mod
OP: lt OP: gt OP: le OP: ge
OP: eq OP: ne OP: and OP: or OP: halt
: GEN ( ast --) 3@ EXECUTE ;
: @; ( r l) DROP DROP ;
: @Identifier fetch i8, i32, DROP ;
: @Integer push i8, i32, DROP ;
: @String push i8, i32, DROP ;
: @Prtc GEN prtc i8, DROP ;
: @Prti GEN prti i8, DROP ;
: @Prts GEN prts i8, DROP ;
: @Not GEN not i8, DROP ;
: @Negate GEN neg i8, DROP ;
: @Sequence GEN GEN ;
: @Assign CELL+ @ >R GEN store i8, R> i32, ;
: @While PC @ SWAP GEN jz i8, HERE >R 0 i32,
SWAP GEN jmp i8, i32, PC @ R> i32! ;
: @If GEN jz i8, HERE >R 0 i32,
CELL+ DUP CELL+ @ DUP @ ['] @; = IF DROP @
ELSE SWAP @ GEN jmp i8, HERE 0 i32, PC @ R> i32! >R
THEN GEN PC @ R> i32! ;
: BINARY >R GEN GEN R> i8, ;
: @Subtract sub BINARY ; : @Add add BINARY ;
: @Mod mod BINARY ; : @Multiply mul BINARY ;
: @Divide div BINARY ;
: @Less lt BINARY ; : @LessEqual le BINARY ;
: @Greater gt BINARY ; : @GreaterEqual ge BINARY ;
: @Equal eq BINARY ; : @NotEqual ne BINARY ;
: @And and BINARY ; : @Or or BINARY ;
: REVERSE ( l -- l') 0 SWAP
BEGIN DUP WHILE TUCK DUP @ ROT ROT ! REPEAT DROP ;
: .STRINGS STRINGS @ REVERSE BEGIN DUP
WHILE DUP FIRST COUNT "TYPE" CR @ REPEAT DROP ;
: .HEADER ( --)
." Datasize: " GLOBALS @ DEPTH . SPACE
." Strings: " STRINGS @ DEPTH . CR .STRINGS ;
: GENERATE ( ast -- addr u)
0 PC ! HERE >R GEN halt i8, R> PC @ ;
: ," [CHAR] " PARSE TUCK HERE SWAP CMOVE ALLOT ;
CREATE "OPS"
," fetch store push jmp jz prtc prti prts "
," neg not add sub mul div mod lt "
," gt le ge eq ne and or halt "
: .i32 i32@+ . ;
: .[i32] [CHAR] [ EMIT .i32 [CHAR] ] EMIT ;
: .off [CHAR] ( EMIT PC @ >R i32@+ DUP R> - . [CHAR] ) EMIT
SPACE . ;
CREATE .INT ' .[i32] , ' .[i32] , ' .i32 , ' .off , ' .off ,
: EMIT ( addr u --) >R 0 PC !
BEGIN PC @ R@ <
WHILE PC @ 5 .R SPACE i8@+
DUP 6 * "OPS" + 6 TYPE
DUP 5 < IF CELLS .INT + @ EXECUTE ELSE DROP THEN CR
REPEAT DROP R> DROP ;
GENERATE EMIT BYE
Passes all tests.
Go
{{trans|C}}
package main
import (
"bufio"
"encoding/binary"
"fmt"
"log"
"os"
"strconv"
"strings"
)
type NodeType int
const (
ndIdent NodeType = iota
ndString
ndInteger
ndSequence
ndIf
ndPrtc
ndPrts
ndPrti
ndWhile
ndAssign
ndNegate
ndNot
ndMul
ndDiv
ndMod
ndAdd
ndSub
ndLss
ndLeq
ndGtr
ndGeq
ndEql
ndNeq
ndAnd
ndOr
)
type code = byte
const (
fetch code = iota
store
push
add
sub
mul
div
mod
lt
gt
le
ge
eq
ne
and
or
neg
not
jmp
jz
prtc
prts
prti
halt
)
type Tree struct {
nodeType NodeType
left *Tree
right *Tree
value string
}
// dependency: Ordered by NodeType, must remain in same order as NodeType enum
type atr struct {
enumText string
nodeType NodeType
opcode code
}
var atrs = []atr{
{"Identifier", ndIdent, 255},
{"String", ndString, 255},
{"Integer", ndInteger, 255},
{"Sequence", ndSequence, 255},
{"If", ndIf, 255},
{"Prtc", ndPrtc, 255},
{"Prts", ndPrts, 255},
{"Prti", ndPrti, 255},
{"While", ndWhile, 255},
{"Assign", ndAssign, 255},
{"Negate", ndNegate, neg},
{"Not", ndNot, not},
{"Multiply", ndMul, mul},
{"Divide", ndDiv, div},
{"Mod", ndMod, mod},
{"Add", ndAdd, add},
{"Subtract", ndSub, sub},
{"Less", ndLss, lt},
{"LessEqual", ndLeq, le},
{"Greater", ndGtr, gt},
{"GreaterEqual", ndGeq, ge},
{"Equal", ndEql, eq},
{"NotEqual", ndNeq, ne},
{"And", ndAnd, and},
{"Or", ndOr, or},
}
var (
stringPool []string
globals []string
object []code
)
var (
err error
scanner *bufio.Scanner
)
func reportError(msg string) {
log.Fatalf("error : %s\n", msg)
}
func check(err error) {
if err != nil {
log.Fatal(err)
}
}
func nodeType2Op(nodeType NodeType) code {
return atrs[nodeType].opcode
}
func makeNode(nodeType NodeType, left *Tree, right *Tree) *Tree {
return &Tree{nodeType, left, right, ""}
}
func makeLeaf(nodeType NodeType, value string) *Tree {
return &Tree{nodeType, nil, nil, value}
}
/*** Code generator ***/
func emitByte(c code) {
object = append(object, c)
}
func emitWord(n int) {
bs := make([]byte, 4)
binary.LittleEndian.PutUint32(bs, uint32(n))
for _, b := range bs {
emitByte(code(b))
}
}
func emitWordAt(at, n int) {
bs := make([]byte, 4)
binary.LittleEndian.PutUint32(bs, uint32(n))
for i := at; i < at+4; i++ {
object[i] = code(bs[i-at])
}
}
func hole() int {
t := len(object)
emitWord(0)
return t
}
func fetchVarOffset(id string) int {
for i := 0; i < len(globals); i++ {
if globals[i] == id {
return i
}
}
globals = append(globals, id)
return len(globals) - 1
}
func fetchStringOffset(st string) int {
for i := 0; i < len(stringPool); i++ {
if stringPool[i] == st {
return i
}
}
stringPool = append(stringPool, st)
return len(stringPool) - 1
}
func codeGen(x *Tree) {
if x == nil {
return
}
var n, p1, p2 int
switch x.nodeType {
case ndIdent:
emitByte(fetch)
n = fetchVarOffset(x.value)
emitWord(n)
case ndInteger:
emitByte(push)
n, err = strconv.Atoi(x.value)
check(err)
emitWord(n)
case ndString:
emitByte(push)
n = fetchStringOffset(x.value)
emitWord(n)
case ndAssign:
n = fetchVarOffset(x.left.value)
codeGen(x.right)
emitByte(store)
emitWord(n)
case ndIf:
codeGen(x.left) // if expr
emitByte(jz) // if false, jump
p1 = hole() // make room forjump dest
codeGen(x.right.left) // if true statements
if x.right.right != nil {
emitByte(jmp)
p2 = hole()
}
emitWordAt(p1, len(object)-p1)
if x.right.right != nil {
codeGen(x.right.right)
emitWordAt(p2, len(object)-p2)
}
case ndWhile:
p1 = len(object)
codeGen(x.left) // while expr
emitByte(jz) // if false, jump
p2 = hole() // make room for jump dest
codeGen(x.right) // statements
emitByte(jmp) // back to the top
emitWord(p1 - len(object)) // plug the top
emitWordAt(p2, len(object)-p2) // plug the 'if false, jump'
case ndSequence:
codeGen(x.left)
codeGen(x.right)
case ndPrtc:
codeGen(x.left)
emitByte(prtc)
case ndPrti:
codeGen(x.left)
emitByte(prti)
case ndPrts:
codeGen(x.left)
emitByte(prts)
case ndLss, ndGtr, ndLeq, ndGeq, ndEql, ndNeq,
ndAnd, ndOr, ndSub, ndAdd, ndDiv, ndMul, ndMod:
codeGen(x.left)
codeGen(x.right)
emitByte(nodeType2Op(x.nodeType))
case ndNegate, ndNot:
codeGen(x.left)
emitByte(nodeType2Op(x.nodeType))
default:
msg := fmt.Sprintf("error in code generator - found %d, expecting operator\n", x.nodeType)
reportError(msg)
}
}
func codeFinish() {
emitByte(halt)
}
func listCode() {
fmt.Printf("Datasize: %d Strings: %d\n", len(globals), len(stringPool))
for _, s := range stringPool {
fmt.Println(s)
}
pc := 0
for pc < len(object) {
fmt.Printf("%5d ", pc)
op := object[pc]
pc++
switch op {
case fetch:
x := int32(binary.LittleEndian.Uint32(object[pc : pc+4]))
fmt.Printf("fetch [%d]\n", x)
pc += 4
case store:
x := int32(binary.LittleEndian.Uint32(object[pc : pc+4]))
fmt.Printf("store [%d]\n", x)
pc += 4
case push:
x := int32(binary.LittleEndian.Uint32(object[pc : pc+4]))
fmt.Printf("push %d\n", x)
pc += 4
case add:
fmt.Println("add")
case sub:
fmt.Println("sub")
case mul:
fmt.Println("mul")
case div:
fmt.Println("div")
case mod:
fmt.Println("mod")
case lt:
fmt.Println("lt")
case gt:
fmt.Println("gt")
case le:
fmt.Println("le")
case ge:
fmt.Println("ge")
case eq:
fmt.Println("eq")
case ne:
fmt.Println("ne")
case and:
fmt.Println("and")
case or:
fmt.Println("or")
case neg:
fmt.Println("neg")
case not:
fmt.Println("not")
case jmp:
x := int32(binary.LittleEndian.Uint32(object[pc : pc+4]))
fmt.Printf("jmp (%d) %d\n", x, int32(pc)+x)
pc += 4
case jz:
x := int32(binary.LittleEndian.Uint32(object[pc : pc+4]))
fmt.Printf("jz (%d) %d\n", x, int32(pc)+x)
pc += 4
case prtc:
fmt.Println("prtc")
case prti:
fmt.Println("prti")
case prts:
fmt.Println("prts")
case halt:
fmt.Println("halt")
default:
reportError(fmt.Sprintf("listCode: Unknown opcode %d", op))
}
}
}
func getEnumValue(name string) NodeType {
for _, atr := range atrs {
if atr.enumText == name {
return atr.nodeType
}
}
reportError(fmt.Sprintf("Unknown token %s\n", name))
return -1
}
func loadAst() *Tree {
var nodeType NodeType
var s string
if scanner.Scan() {
line := strings.TrimRight(scanner.Text(), " \t")
tokens := strings.Fields(line)
first := tokens[0]
if first[0] == ';' {
return nil
}
nodeType = getEnumValue(first)
le := len(tokens)
if le == 2 {
s = tokens[1]
} else if le > 2 {
idx := strings.Index(line, `"`)
s = line[idx:]
}
}
check(scanner.Err())
if s != "" {
return makeLeaf(nodeType, s)
}
left := loadAst()
right := loadAst()
return makeNode(nodeType, left, right)
}
func main() {
ast, err := os.Open("ast.txt")
check(err)
defer ast.Close()
scanner = bufio.NewScanner(ast)
codeGen(loadAst())
codeFinish()
listCode()
}
{{out}} while counter example:
Datasize: 1 Strings: 2
"count is: "
"\n"
0 push 1
5 store [0]
10 fetch [0]
15 push 10
20 lt
21 jz (43) 65
26 push 0
31 prts
32 fetch [0]
37 prti
38 push 1
43 prts
44 fetch [0]
49 push 1
54 add
55 store [0]
60 jmp (-51) 10
65 halt
Java
{{trans|Python}}
package codegenerator;
import java.io.File;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.Scanner;
public class CodeGenerator {
final static int WORDSIZE = 4;
static byte[] code = {};
static Map<String, NodeType> str_to_nodes = new HashMap<>();
static List<String> string_pool = new ArrayList<>();
static List<String> variables = new ArrayList<>();
static int string_count = 0;
static int var_count = 0;
static Scanner s;
static NodeType[] unary_ops = {
NodeType.nd_Negate, NodeType.nd_Not
};
static NodeType[] operators = {
NodeType.nd_Mul, NodeType.nd_Div, NodeType.nd_Mod, NodeType.nd_Add, NodeType.nd_Sub,
NodeType.nd_Lss, NodeType.nd_Leq, NodeType.nd_Gtr, NodeType.nd_Geq,
NodeType.nd_Eql, NodeType.nd_Neq, NodeType.nd_And, NodeType.nd_Or
};
static enum Mnemonic {
NONE, FETCH, STORE, PUSH, ADD, SUB, MUL, DIV, MOD, LT, GT, LE, GE, EQ, NE, AND, OR, NEG, NOT,
JMP, JZ, PRTC, PRTS, PRTI, HALT
}
static class Node {
public NodeType nt;
public Node left, right;
public String value;
Node() {
this.nt = null;
this.left = null;
this.right = null;
this.value = null;
}
Node(NodeType node_type, Node left, Node right, String value) {
this.nt = node_type;
this.left = left;
this.right = right;
this.value = value;
}
public static Node make_node(NodeType nodetype, Node left, Node right) {
return new Node(nodetype, left, right, "");
}
public static Node make_node(NodeType nodetype, Node left) {
return new Node(nodetype, left, null, "");
}
public static Node make_leaf(NodeType nodetype, String value) {
return new Node(nodetype, null, null, value);
}
}
static enum NodeType {
nd_None("", Mnemonic.NONE), nd_Ident("Identifier", Mnemonic.NONE), nd_String("String", Mnemonic.NONE), nd_Integer("Integer", Mnemonic.NONE), nd_Sequence("Sequence", Mnemonic.NONE),
nd_If("If", Mnemonic.NONE),
nd_Prtc("Prtc", Mnemonic.NONE), nd_Prts("Prts", Mnemonic.NONE), nd_Prti("Prti", Mnemonic.NONE), nd_While("While", Mnemonic.NONE),
nd_Assign("Assign", Mnemonic.NONE),
nd_Negate("Negate", Mnemonic.NEG), nd_Not("Not", Mnemonic.NOT), nd_Mul("Multiply", Mnemonic.MUL), nd_Div("Divide", Mnemonic.DIV), nd_Mod("Mod", Mnemonic.MOD), nd_Add("Add", Mnemonic.ADD),
nd_Sub("Subtract", Mnemonic.SUB), nd_Lss("Less", Mnemonic.LT), nd_Leq("LessEqual", Mnemonic.LE),
nd_Gtr("Greater", Mnemonic.GT), nd_Geq("GreaterEqual", Mnemonic.GE), nd_Eql("Equal", Mnemonic.EQ),
nd_Neq("NotEqual", Mnemonic.NE), nd_And("And", Mnemonic.AND), nd_Or("Or", Mnemonic.OR);
private final String name;
private final Mnemonic m;
NodeType(String name, Mnemonic m) {
this.name = name;
this.m = m;
}
Mnemonic getMnemonic() { return this.m; }
@Override
public String toString() { return this.name; }
}
static void appendToCode(int b) {
code = Arrays.copyOf(code, code.length + 1);
code[code.length - 1] = (byte) b;
}
static void emit_byte(Mnemonic m) {
appendToCode(m.ordinal());
}
static void emit_word(int n) {
appendToCode(n >> 24);
appendToCode(n >> 16);
appendToCode(n >> 8);
appendToCode(n);
}
static void emit_word_at(int pos, int n) {
code[pos] = (byte) (n >> 24);
code[pos + 1] = (byte) (n >> 16);
code[pos + 2] = (byte) (n >> 8);
code[pos + 3] = (byte) n;
}
static int get_word(int pos) {
int result;
result = ((code[pos] & 0xff) << 24) + ((code[pos + 1] & 0xff) << 16) + ((code[pos + 2] & 0xff) << 8) + (code[pos + 3] & 0xff) ;
return result;
}
static int fetch_var_offset(String name) {
int n;
n = variables.indexOf(name);
if (n == -1) {
variables.add(name);
n = var_count++;
}
return n;
}
static int fetch_string_offset(String str) {
int n;
n = string_pool.indexOf(str);
if (n == -1) {
string_pool.add(str);
n = string_count++;
}
return n;
}
static int hole() {
int t = code.length;
emit_word(0);
return t;
}
static boolean arrayContains(NodeType[] a, NodeType n) {
boolean result = false;
for (NodeType test: a) {
if (test.equals(n)) {
result = true;
break;
}
}
return result;
}
static void code_gen(Node x) throws Exception {
int n, p1, p2;
if (x == null) return;
switch (x.nt) {
case nd_None: return;
case nd_Ident:
emit_byte(Mnemonic.FETCH);
n = fetch_var_offset(x.value);
emit_word(n);
break;
case nd_Integer:
emit_byte(Mnemonic.PUSH);
emit_word(Integer.parseInt(x.value));
break;
case nd_String:
emit_byte(Mnemonic.PUSH);
n = fetch_string_offset(x.value);
emit_word(n);
break;
case nd_Assign:
n = fetch_var_offset(x.left.value);
code_gen(x.right);
emit_byte(Mnemonic.STORE);
emit_word(n);
break;
case nd_If:
p2 = 0; // to avoid NetBeans complaining about 'not initialized'
code_gen(x.left);
emit_byte(Mnemonic.JZ);
p1 = hole();
code_gen(x.right.left);
if (x.right.right != null) {
emit_byte(Mnemonic.JMP);
p2 = hole();
}
emit_word_at(p1, code.length - p1);
if (x.right.right != null) {
code_gen(x.right.right);
emit_word_at(p2, code.length - p2);
}
break;
case nd_While:
p1 = code.length;
code_gen(x.left);
emit_byte(Mnemonic.JZ);
p2 = hole();
code_gen(x.right);
emit_byte(Mnemonic.JMP);
emit_word(p1 - code.length);
emit_word_at(p2, code.length - p2);
break;
case nd_Sequence:
code_gen(x.left);
code_gen(x.right);
break;
case nd_Prtc:
code_gen(x.left);
emit_byte(Mnemonic.PRTC);
break;
case nd_Prti:
code_gen(x.left);
emit_byte(Mnemonic.PRTI);
break;
case nd_Prts:
code_gen(x.left);
emit_byte(Mnemonic.PRTS);
break;
default:
if (arrayContains(operators, x.nt)) {
code_gen(x.left);
code_gen(x.right);
emit_byte(x.nt.getMnemonic());
} else if (arrayContains(unary_ops, x.nt)) {
code_gen(x.left);
emit_byte(x.nt.getMnemonic());
} else {
throw new Exception("Error in code generator! Found " + x.nt + ", expecting operator.");
}
}
}
static void list_code() throws Exception {
int pc = 0, x;
Mnemonic op;
System.out.println("Datasize: " + var_count + " Strings: " + string_count);
for (String s: string_pool) {
System.out.println(s);
}
while (pc < code.length) {
System.out.printf("%4d ", pc);
op = Mnemonic.values()[code[pc++]];
switch (op) {
case FETCH:
x = get_word(pc);
System.out.printf("fetch [%d]", x);
pc += WORDSIZE;
break;
case STORE:
x = get_word(pc);
System.out.printf("store [%d]", x);
pc += WORDSIZE;
break;
case PUSH:
x = get_word(pc);
System.out.printf("push %d", x);
pc += WORDSIZE;
break;
case ADD: case SUB: case MUL: case DIV: case MOD:
case LT: case GT: case LE: case GE: case EQ: case NE:
case AND: case OR: case NEG: case NOT:
case PRTC: case PRTI: case PRTS: case HALT:
System.out.print(op.toString().toLowerCase());
break;
case JMP:
x = get_word(pc);
System.out.printf("jmp (%d) %d", x, pc + x);
pc += WORDSIZE;
break;
case JZ:
x = get_word(pc);
System.out.printf("jz (%d) %d", x, pc + x);
pc += WORDSIZE;
break;
default:
throw new Exception("Unknown opcode " + code[pc] + "@" + (pc - 1));
}
System.out.println();
}
}
static Node load_ast() throws Exception {
String command, value;
String line;
Node left, right;
while (s.hasNext()) {
line = s.nextLine();
value = null;
if (line.length() > 16) {
command = line.substring(0, 15).trim();
value = line.substring(15).trim();
} else {
command = line.trim();
}
if (command.equals(";")) {
return null;
}
if (!str_to_nodes.containsKey(command)) {
throw new Exception("Command not found: '" + command + "'");
}
if (value != null) {
return Node.make_leaf(str_to_nodes.get(command), value);
}
left = load_ast(); right = load_ast();
return Node.make_node(str_to_nodes.get(command), left, right);
}
return null; // for the compiler, not needed
}
public static void main(String[] args) {
Node n;
str_to_nodes.put(";", NodeType.nd_None);
str_to_nodes.put("Sequence", NodeType.nd_Sequence);
str_to_nodes.put("Identifier", NodeType.nd_Ident);
str_to_nodes.put("String", NodeType.nd_String);
str_to_nodes.put("Integer", NodeType.nd_Integer);
str_to_nodes.put("If", NodeType.nd_If);
str_to_nodes.put("While", NodeType.nd_While);
str_to_nodes.put("Prtc", NodeType.nd_Prtc);
str_to_nodes.put("Prts", NodeType.nd_Prts);
str_to_nodes.put("Prti", NodeType.nd_Prti);
str_to_nodes.put("Assign", NodeType.nd_Assign);
str_to_nodes.put("Negate", NodeType.nd_Negate);
str_to_nodes.put("Not", NodeType.nd_Not);
str_to_nodes.put("Multiply", NodeType.nd_Mul);
str_to_nodes.put("Divide", NodeType.nd_Div);
str_to_nodes.put("Mod", NodeType.nd_Mod);
str_to_nodes.put("Add", NodeType.nd_Add);
str_to_nodes.put("Subtract", NodeType.nd_Sub);
str_to_nodes.put("Less", NodeType.nd_Lss);
str_to_nodes.put("LessEqual", NodeType.nd_Leq);
str_to_nodes.put("Greater", NodeType.nd_Gtr);
str_to_nodes.put("GreaterEqual", NodeType.nd_Geq);
str_to_nodes.put("Equal", NodeType.nd_Eql);
str_to_nodes.put("NotEqual", NodeType.nd_Neq);
str_to_nodes.put("And", NodeType.nd_And);
str_to_nodes.put("Or", NodeType.nd_Or);
if (args.length > 0) {
try {
s = new Scanner(new File(args[0]));
n = load_ast();
code_gen(n);
emit_byte(Mnemonic.HALT);
list_code();
} catch (Exception e) {
System.out.println("Ex: "+e);//.getMessage());
}
}
}
}
Julia
import Base.show
mutable struct Asm32
offset::Int32
code::String
arg::Int32
targ::Int32
end
Asm32(code, arg = 0) = Asm32(0, code, arg, 0)
show(io::IO, a::Asm32) = print(io, lpad("$(a.offset)", 6), lpad(a.code, 8),
a.targ > 0 ? (lpad("($(a.arg))", 8) * lpad("$(a.targ)", 4)) :
(a.code in ["store", "fetch"] ? lpad("[$(a.arg)]", 8) :
(a.code in ["push"] ? lpad("$(a.arg)", 8) : "")))
const ops32 = Dict{String,String}("Multiply" => "mul", "Divide" => "div", "Mod" => "mod", "Add" => "add",
"Subtract" => "sub", "Less" => "lt", "Greater" => "gt", "LessEqual" => "le", "GreaterEqual" => "ge",
"Equal" => "eq", "NotEqual" => "ne", "And" => "and", "or" => "or", "Not" => "not", "Minus" => "neg",
"Prtc" => "prtc", "Prti" => "prti", "Prts" => "prts")
function compiletoasm(io)
identifiers = Vector{String}()
strings = Vector{String}()
labels = Vector{Int}()
function cpile(io, islefthandside = false)
arr = Vector{Asm32}()
jlabel() = (push!(labels, length(labels) + 1); labels[end])
m = match(r"^(\w+|;)\s*([\d\w\"\\ \S]+)?", strip(readline(io)))
x, val = m == nothing ? Pair(";", 0) : m.captures
if x == ";" return arr
elseif x == "Assign"
lhs = cpile(io, true)
rhs = cpile(io)
append!(arr, rhs)
append!(arr, lhs)
if length(arr) > 100 exit() end
elseif x == "Integer" push!(arr, Asm32("push", parse(Int32, val)))
elseif x == "String"
if !(val in strings)
push!(strings, val)
end
push!(arr, Asm32("push", findfirst(x -> x == val, strings) - 1))
elseif x == "Identifier"
if !(val in identifiers)
if !islefthandside
throw("Identifier $val referenced before it is assigned")
end
push!(identifiers, val)
end
push!(arr, Asm32(islefthandside ? "store" : "fetch", findfirst(x -> x == val, identifiers) - 1))
elseif haskey(ops32, x)
append!(arr, cpile(io))
append!(arr, cpile(io))
push!(arr, Asm32(ops32[x]))
elseif x == "If"
append!(arr, cpile(io))
x, y = jlabel(), jlabel()
push!(arr, Asm32("jz", x))
append!(arr, cpile(io))
push!(arr, Asm32("jmp", y))
a = cpile(io)
if length(a) < 1
push!(a, Asm32("nop", 0))
end
a[1].offset = x
append!(arr, a)
push!(arr, Asm32(y, "nop", 0, 0)) # placeholder
elseif x == "While"
x, y = jlabel(), jlabel()
a = cpile(io)
if length(a) < 1
push!(a, Asm32("nop", 0))
end
a[1].offset = x
append!(arr, a)
push!(arr, Asm32("jz", y))
append!(arr, cpile(io))
push!(arr, Asm32("jmp", x), Asm32(y, "nop", 0, 0))
elseif x == "Sequence"
append!(arr, cpile(io))
append!(arr, cpile(io))
else
throw("unknown node type: $x")
end
arr
end
# compile AST
asmarr = cpile(io)
push!(asmarr, Asm32("halt"))
# move address markers to working code and prune nop code
for (i, acode) in enumerate(asmarr)
if acode.code == "nop" && acode.offset != 0 && i < length(asmarr)
asmarr[i + 1].offset = asmarr[i].offset
end
end
filter!(x -> x.code != "nop", asmarr)
# renumber offset column with actual offsets
pos = 0
jmps = Dict{Int, Int}()
for acode in asmarr
if acode.offset > 0
jmps[acode.offset] = pos
end
acode.offset = pos
pos += acode.code in ["push", "store", "fetch", "jz", "jmp"] ? 5 : 1
end
# fix up jump destinations
for acode in asmarr
if acode.code in ["jz", "jmp"]
if haskey(jmps, acode.arg)
acode.targ = jmps[acode.arg]
acode.arg = acode.targ - acode.offset -1
else
throw("unknown jump location: $acode")
end
end
end
# print Datasize and Strings header
println("Datasize: $(length(identifiers)) Strings: $(length(strings))\n" *
join(strings, "\n") )
# print assembly lines
foreach(println, asmarr)
end
const testAST = raw"""
Sequence
Sequence
;
Assign
Identifier count
Integer 1
While
Less
Identifier count
Integer 10
Sequence
Sequence
;
Sequence
Sequence
Sequence
;
Prts
String "count is: "
;
Prti
Identifier count
;
Prts
String "\n"
;
Assign
Identifier count
Add
Identifier count
Integer 1 """
iob = IOBuffer(testAST) # use an io buffer here for testing, but could use stdin instead of iob
compiletoasm(iob)
{{output}}
Datasize: 1 Strings: 2
"count is: "
"\n"
0 push 1
5 store [0]
10 fetch [0]
15 push 10
20 lt
21 jz (43) 65
26 push 0
31 prts
32 fetch [0]
37 prti
38 push 1
43 prts
44 fetch [0]
49 push 1
54 add
55 store [0]
60 jmp (-51) 10
65 halt
M2000 Interpreter
Module CodeGenerator (s$){
Function code$(op$) {
=format$("{0::-6} {1}", pc, op$)
pc++
}
Function code2$(op$, n$) {
=format$("{0::-6} {1} {2}", pc, op$, n$)
pc+=5
}
Function code3$(op$,pc, st, ed) {
=format$("{0::-6} {1} ({2}) {3}", pc, op$, ed-st-1, ed)
}
Enum tok {
gneg, gnot, gmul, gdiv, gmod, gadd, gle, gsub, glt
gle, ggt, gge, geq, gne, gand, gor, gprtc, gprti, gprts,
gif, gwhile, gAssign, gSeq, gstring, gidentifier, gint, gnone
}
\\ Inventories are lists with keys, or keys/data (key must be unique)
\\ there is one type more the Invetory Queue which get same keys.
\\ But here not used.
Inventory symb="Multiply":=gmul, "Divide":=gdiv, "Mod":=gmod, "Add":=gadd
Append symb, "Negate":=gneg, "Not":=gnot,"Less":=glt,"Subtract":=gsub
Append symb, "LessEqual":=gle, "Greater":=ggt, "GreaterEqual":=gge, "Sequence":=gSeq
Append symb, "Equal":=geq, "NotEqual":=gne, "And":=gand, "Or":=gor, "While":=gwhile
Append symb, "Prtc":=gprtc,"Prti":=gprti,"Prts":=gprts, "Assign":=gAssign, "If":=gif
Append symb, "String":=gstring, "Identifier":=gidentifier, "Integer":=gint, ";", gnone
Inventory DataSet
\\ We set string as key. key maybe an empty string, a string or a number.
\\ so we want eash string to saved one time only.
Inventory Strings
Const nl$=chr$(13)+chr$(10), Ansi=3
Def z$, lim, line$, newvar_ok, i=0
Document message$=nl$
Global pc \\ functions have own scope, so we make it global, for this module, and childs.
Dim lines$()
s$=filter$(s$,chr$(9)) \\ exclude tabs
Lines$()=piece$(s$,nl$) \\ break to lines
lim=len(Lines$())
Flush ' empty stack (there is a current stack of values which we use here)
Load_Ast()
If not stack.size=1 Then Flush : Error "Ast not loaded"
AST=array \\ pop the array from stack
Document Assembly$, Header$
\\ all lines of assembly goes to stack. Maybe not in right order.
\\ Push statement push to top, Data statement push to bottom of stack
CodeGenerator(Ast)
Data code$("halt") ' append to end of stack
\\ So now we get all data (letters) from stack
While not empty
Assembly$=letter$+nl$
end while
\\ So now we have to place them in order
Sort Assembly$
\\ Let's make the header
Header$=format$("Datasize: {0} Strings: {1}", Len(Dataset),Len(strings))
\\ we use an iterator object, str^ is the counter, readonly, but Eval$() use it from object.
str=each(strings)
While str
Header$=nl$+Eval$(str)
End while
Assembly$=nl$
\\ insert to line 1 the Header
Insert 1 Assembly$=Header$
\\ Also we check for warnings
If len(message$)>2 then Assembly$="Warnings: "+nl$+message$
\\ So now we get a report
\\ (at each 3/4 of window's lines, the printing stop and wait for user response, any key)
Report Assembly$
Clipboard Assembly$
Save.Doc Assembly$, "code.t", Ansi
End
\\ subs have 10000 limit for recursion but can be extended to 1000000 or more.
Sub CodeGenerator(t)
If len(t)=3 then
select case t#val(0)
Case gSeq
CodeGenerator(t#val(1)) : CodeGenerator(t#val(2))
Case gwhile
{
local spc=pc
CodeGenerator(t#val(1))
local pc1=pc
pc+=5 ' room for jz
CodeGenerator(t#val(2))
data code3$("jz",pc1, pc1, pc+5)
data code3$("jmp",pc, pc, spc)
pc+=5 ' room for jmp
}
Case gif
{
CodeGenerator(t#val(1))
local pc1=pc, pc2
pc+=5
CodeGenerator(t#val(2)#val(1))
If len(t#val(2)#val(2))>0 then
pc2=pc
pc+=5
data code3$("jz",pc1, pc1, pc)
CodeGenerator(t#val(2)#val(2))
data code3$("jmp",pc2, pc2, pc)
else
data code3$("jz",pc1, pc1, pc)
end If
}
Case gAssign
{
CodeGenerator(t#val(2))
local newvar_ok=true
CodeGenerator(t#val(1))
}
case gneg to gnot, gprtc to gprts
CodeGenerator(t#val(1)) : data code$(mid$(eval$(t#val(0)),2))
case gmul to gor
{
CodeGenerator(t#val(1))
CodeGenerator(t#val(2))
data code$(mid$(eval$(t#val(0)),2))
}
End select
Else.if len(t)=2 then
select case t#val(0)
Case gString
{
local spos
If exist(strings,t#val$(1)) then
spos=eval(strings!)
else
append strings, t#val$(1)
spos=len(strings)-1
end If
Push code2$("push",str$(spos,0))
}
Case gInt
Push code2$("push",t#val$(1), pc)
Case gIdentifier
{
local ipos
If exist(dataset,t#val$(1)) then
ipos=Eval(dataset!) ' return position
else.if newvar_ok then
Append dataset, t#val$(1)
ipos=len(dataset)-1
else
message$="Variable "+t#val$(1)+" not initialized"+nl$
end If
If newvar_ok then
Push code2$("store","["+str$(ipos, 0)+"]")
else
Push code2$("fetch","["+str$(ipos, 0)+"]")
end If
}
end select
End If
End Sub
Sub Load_Ast()
If i>=lim then Push (,) : exit sub
do
line$=Trim$(lines$(i))
I++
tok$=piece$(line$," ")(0)
until line$<>"" or i>=lim
If tok$="Identifier" then
Push (gidentifier,trim$(Mid$(line$,11)))
else.if tok$="Integer" then
long n=Val(Mid$(line$,8)) ' check overflow
Push (gint, Trim$(Mid$(line$,8)))
else.if tok$="String" then
Push (gstring,Trim$(Mid$(line$,7)))
else.if tok$=";" then
Push (,)
Else
local otok=symb(tok$)
Load_Ast()
Load_Ast()
Shift 2
Push (otok,array, array)
End If
End Sub
}
CodeGenerator {
Sequence
Sequence
;
Assign
Identifier count
Integer 1
While
Less
Identifier count
Integer 10
Sequence
Sequence
;
Sequence
Sequence
Sequence
;
Prts
String "count is: "
;
Prti
Identifier count
;
Prts
String "\n"
;
Assign
Identifier count
Add
Identifier count
Integer 1
}
{{out}}
Datasize: 1 Strings: 2
"count is: "
"\n"
0 push
5 store [0]
10 fetch [0]
15 push
20 lt
21 jz (43) 65
26 push 0
31 prts
32 fetch [0]
37 prti
38 push 1
43 prts
44 fetch [0]
49 push
54 add
55 store [0]
60 jmp (-51) 10
65 halt
## Perl
Tested with perl v5.26.1
```Perl
#!/usr/bin/perl
use strict; # gen.pl - flatAST to stack machine code
use warnings; # http://www.rosettacode.org/wiki/Compiler/code_generator
my $stringcount = my $namecount = my $pairsym = my $pc = 0;
my (%strings, %names);
my %opnames = qw( Less lt LessEqual le Multiply mul Subtract sub Divide div
GreaterEqual ge Equal eq Greater gt NotEqual ne Negate neg );
sub tree
{
my ($A, $B) = ( '_' . ++$pairsym, '_' . ++$pairsym ); # labels for jumps
my $line = <> // return '';
(local $_, my $arg) = $line =~ /^(\w+|;)\s+(.*)/ or die "bad input $line";
/Identifier/ ? "fetch [@{[ $names{$arg} //= $namecount++ ]}]\n" :
/Sequence/ ? tree() . tree() :
/Integer/ ? "push $arg\n" :
/String/ ? "push @{[ $strings{$arg} //= $stringcount++ ]}\n" :
/Assign/ ? join '', reverse tree() =~ s/fetch/store/r, tree() :
/While/ ? "$A:\n@{[ tree() ]}jz $B\n@{[ tree() ]}jmp $A\n$B:\n" :
/If/ ? tree() . "jz $A\n@{[ !<> . # !<> skips second 'If'
tree() ]}jmp $B\n$A:\n@{[ tree() ]}$B:\n" :
/;/ ? '' :
tree() . tree() . ($opnames{$_} // lc) . "\n";
}
$_ = tree() . "halt\n";
s/^jmp\s+(\S+)\n(_\d+:\n)\1:\n/$2/gm; # remove jmp next
s/^(?=[a-z]\w*(.*))/ # add locations
(sprintf("%4d ", $pc), $pc += $1 ? 5 : 1)[0] /gem;
my %labels = /^(_\d+):(?=(?:\n_\d+:)*\n *(\d+) )/gm; # pc addr of labels
s/^ *(\d+) j(?:z|mp) *\K(_\d+)$/ (@{[ # fix jumps
$labels{$2} - $1 - 1]}) $labels{$2}/gm;
s/^_\d+.*\n//gm; # remove labels
print "Datasize: $namecount Strings: $stringcount\n";
print "$_\n" for sort { $strings{$a} <=> $strings{$b} } keys %strings;
print;
```
Passes all tests.
## Phix
Reusing parse.e from the [[Compiler/syntax_analyzer#Phix|Syntax Analyzer task]]
Deviates somewhat from the task specification in that it generates executable machine code.
```Phix
--
-- demo\rosetta\Compiler\cgen.e
--
### ======================
--
-- The reusable part of cgen.exw
--
include parse.e
global sequence vars = {},
strings = {},
stringptrs = {}
global integer chain = 0
global sequence code = {}
function var_idx(sequence inode)
if inode[1]!=tk_Identifier then ?9/0 end if
string ident = inode[2]
integer n = find(ident,vars)
if n=0 then
vars = append(vars,ident)
n = length(vars)
end if
return n
end function
function string_idx(sequence inode)
if inode[1]!=tk_String then ?9/0 end if
string s = inode[2]
integer n = find(s,strings)
if n=0 then
strings = append(strings,s)
stringptrs = append(stringptrs,0)
n = length(strings)
end if
return n
end function
function gen_size(object t)
-- note: must be kept precisely in sync with gen_rec!
-- (relentlessly tested via estsize/actsize)
integer size = 0
if t!=NULL then
integer n_type = t[1]
string node_type = tkNames[n_type]
switch n_type do
case tk_Sequence:
size += gen_size(t[2])
size += gen_size(t[3])
case tk_assign:
size += gen_size(t[3])+6
case tk_Integer:
size += 5
case tk_Identifier:
size += 6
case tk_String:
size += 5
case tk_while:
-- emit: @@: