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Use growable buffers for bytecode and strings.

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Ensures the compiler can handle long chunks of code and strings.
This commit is contained in:
Bob Nystrom
2013-12-27 07:22:43 -08:00
parent 3506a39e27
commit a8c725ea3f
3 changed files with 1097 additions and 35 deletions
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106
src/wren_compiler.c
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@ -123,6 +123,14 @@ typedef struct Token_s
int line;
} Token;
// A growable byte buffer.
typedef struct
{
uint8_t* bytes;
int length;
int capacity;
} Buffer;
typedef struct
{
WrenVM* vm;
@ -150,12 +158,10 @@ typedef struct
// If a syntax or compile error has occurred.
bool hasError;
// TODO: Dynamically allocate this.
// A buffer for the unescaped text of the current token if it's a string
// literal. Unlike the raw token, this will have escape sequences translated
// to their literal equivalent.
char currentString[MAX_STRING];
int currentStringLength;
Buffer string;
} Parser;
typedef struct
@ -195,10 +201,7 @@ struct sCompiler
struct sCompiler* parent;
// The growable buffer of code that's been compiled so far.
uint8_t* bytecode;
// The number of bytes of code generated so far.
int bytecodeLength;
Buffer bytecode;
ObjList* constants;
@ -310,6 +313,40 @@ static int addConstant(Compiler* compiler, Value constant)
return compiler->constants->count - 1;
}
static void initBuffer(WrenVM* vm, Buffer* buffer)
{
buffer->bytes = NULL;
buffer->capacity = 0;
buffer->length = 0;
}
static void ensureBufferCapacity(WrenVM* vm, Buffer* buffer, int needed)
{
// Do nothing if already big enough.
if (buffer->capacity >= needed) return;
// Give it an initial bump, then double each time.
int capacity = buffer->capacity == 0 ? 2 : buffer->capacity * 2;
buffer->bytes = wrenReallocate(vm, buffer->bytes,
buffer->capacity, capacity);
// TODO: Handle allocation failure.
buffer->capacity = capacity;
}
static void writeBuffer(WrenVM* vm, Buffer* buffer, uint8_t byte)
{
ensureBufferCapacity(vm, buffer, buffer->length + 1);
buffer->bytes[buffer->length++] = byte;
}
static void freeBuffer(WrenVM* vm, Buffer* buffer)
{
wrenReallocate(vm, buffer->bytes, buffer->capacity, 0);
buffer->bytes = NULL;
buffer->capacity = 0;
buffer->length = 0;
}
// Initializes [compiler].
static void initCompiler(Compiler* compiler, Parser* parser, Compiler* parent,
const char* methodName, int methodLength)
@ -317,24 +354,21 @@ static void initCompiler(Compiler* compiler, Parser* parser, Compiler* parent,
// TODO: Reorganize initialization and fields to be in same order as struct.
compiler->parser = parser;
compiler->parent = parent;
compiler->bytecodeLength = 0;
compiler->loopBody = -1;
compiler->methodName = methodName;
compiler->methodLength = methodLength;
initBuffer(parser->vm, &compiler->bytecode);
// Initialize these to NULL before allocating them in case a GC gets
// triggered in the middle of creating these.
compiler->constants = NULL;
compiler->bytecode = NULL;
wrenSetCompiler(parser->vm, compiler);
// Create a growable list for the constants used by this function.
compiler->constants = wrenNewList(parser->vm, 0);
// TODO: Make initial size smaller.
compiler->bytecode = wrenReallocate(parser->vm, NULL, 0, 2048);
compiler->numUpvalues = 0;
if (parent == NULL)
@ -537,13 +571,14 @@ static void readName(Parser* parser, TokenType type)
// Adds [c] to the current string literal being tokenized.
static void addStringChar(Parser* parser, char c)
{
parser->currentString[parser->currentStringLength++] = c;
writeBuffer(parser->vm, &parser->string, c);
}
// Finishes lexing a string literal.
static void readString(Parser* parser)
{
parser->currentStringLength = 0;
freeBuffer(parser->vm, &parser->string);
for (;;)
{
char c = nextChar(parser);
@ -815,11 +850,8 @@ static Token* consume(Compiler* compiler, TokenType expected,
// Emits one bytecode instruction or argument. Returns its index.
static int emit(Compiler* compiler, Code code)
{
// TODO: Grow buffer if needed.
compiler->bytecode[compiler->bytecodeLength] = code;
compiler->bytecodeLength++;
return compiler->bytecodeLength - 1;
writeBuffer(compiler->parser->vm, &compiler->bytecode, code);
return compiler->bytecode.length - 1;
}
// Emits one bytecode instruction followed by an argument. Returns the index of
@ -1071,8 +1103,8 @@ static ObjFn* endCompiler(Compiler* compiler)
if (compiler->parser->hasError)
{
// Free the bytecode since it won't be used.
wrenReallocate(compiler->parser->vm, compiler->bytecode, 0, 0);
freeBuffer(compiler->parser->vm, &compiler->bytecode);
return NULL;
}
@ -1085,8 +1117,8 @@ static ObjFn* endCompiler(Compiler* compiler)
compiler->constants->elements,
compiler->constants->count,
compiler->numUpvalues,
compiler->bytecode,
compiler->bytecodeLength);
compiler->bytecode.bytes,
compiler->bytecode.length);
PinnedObj pinned;
pinObj(compiler->parser->vm, (Obj*)fn, &pinned);
@ -1170,7 +1202,7 @@ GrammarRule rules[];
// instruction with an offset that jumps to the current end of bytecode.
static void patchJump(Compiler* compiler, int offset)
{
compiler->bytecode[offset] = compiler->bytecodeLength - offset - 1;
compiler->bytecode.bytes[offset] = compiler->bytecode.length - offset - 1;
}
// Parses a block body, after the initial "{" has been consumed.
@ -1482,7 +1514,9 @@ static void string(Compiler* compiler, bool allowAssignment)
{
// Define a constant for the literal.
int constant = addConstant(compiler, wrenNewString(compiler->parser->vm,
compiler->parser->currentString, compiler->parser->currentStringLength));
(char*)compiler->parser->string.bytes, compiler->parser->string.length));
freeBuffer(compiler->parser->vm, &compiler->parser->string);
// Compile the code to load the constant.
emit1(compiler, CODE_CONSTANT, constant);
@ -1912,7 +1946,7 @@ static int getNumArguments(const uint8_t* bytecode, const Value* constants,
static int startLoopBody(Compiler* compiler)
{
int outerLoopBody = compiler->loopBody;
compiler->loopBody = compiler->bytecodeLength;
compiler->loopBody = compiler->bytecode.length;
return outerLoopBody;
}
@ -1921,18 +1955,18 @@ static void endLoopBody(Compiler* compiler, int outerLoopBody)
// Find any break placeholder instructions (which will be CODE_END in the
// bytecode) and replace them with real jumps.
int i = compiler->loopBody;
while (i < compiler->bytecodeLength)
while (i < compiler->bytecode.length)
{
if (compiler->bytecode[i] == CODE_END)
if (compiler->bytecode.bytes[i] == CODE_END)
{
compiler->bytecode[i] = CODE_JUMP;
compiler->bytecode.bytes[i] = CODE_JUMP;
patchJump(compiler, i + 1);
i += 2;
}
else
{
// Skip this instruction and its arguments.
i += 1 + getNumArguments(compiler->bytecode,
i += 1 + getNumArguments(compiler->bytecode.bytes,
compiler->constants->elements, i);
}
}
@ -1998,7 +2032,7 @@ static void forStatement(Compiler* compiler)
consume(compiler, TOKEN_RIGHT_PAREN, "Expect ')' after loop expression.");
// Remember what instruction to loop back to.
int loopStart = compiler->bytecodeLength - 1;
int loopStart = compiler->bytecode.length - 1;
// Advance the iterator by calling the ".iterate" method on the sequence.
emit1(compiler, CODE_LOAD_LOCAL, seqSlot);
@ -2037,7 +2071,7 @@ static void forStatement(Compiler* compiler)
// Loop back to the top.
emit(compiler, CODE_LOOP);
int loopOffset = compiler->bytecodeLength - loopStart;
int loopOffset = compiler->bytecode.length - loopStart;
emit(compiler, loopOffset);
patchJump(compiler, exitJump);
@ -2049,7 +2083,7 @@ static void forStatement(Compiler* compiler)
static void whileStatement(Compiler* compiler)
{
// Remember what instruction to loop back to.
int loopStart = compiler->bytecodeLength - 1;
int loopStart = compiler->bytecode.length - 1;
// Compile the condition.
consume(compiler, TOKEN_LEFT_PAREN, "Expect '(' after 'while'.");
@ -2064,7 +2098,7 @@ static void whileStatement(Compiler* compiler)
// Loop back to the top.
emit(compiler, CODE_LOOP);
int loopOffset = compiler->bytecodeLength - loopStart;
int loopOffset = compiler->bytecode.length - loopStart;
emit(compiler, loopOffset);
patchJump(compiler, exitJump);
@ -2214,7 +2248,7 @@ static void classDefinition(Compiler* compiler)
}
// Update the class with the number of fields.
compiler->bytecode[numFieldsInstruction] = fields.count;
compiler->bytecode.bytes[numFieldsInstruction] = fields.count;
compiler->fields = previousFields;
// Store it in its name.
@ -2274,6 +2308,8 @@ ObjFn* wrenCompile(WrenVM* vm, const char* source)
parser.current.length = 0;
parser.current.line = 0;
initBuffer(vm, &parser.string);
// Read the first token.
nextToken(&parser);

1013
test/long_function.wren Normal file
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13
test/long_string.wren Normal file
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@ -0,0 +1,13 @@
// Create a very long string containing escape sequences.
var s = "1234567890\"1234567890\"1234567890\"1234567890\"1234567890\"1234567890\"1234567890\"1234567890\"1234567890\"1234567890\n1234567890\"1234567890\"1234567890\"1234567890\"1234567890\"1234567890\"1234567890\"1234567890\"1234567890\"1234567890\n1234567890\"1234567890\"1234567890\"1234567890\"1234567890\"1234567890\"1234567890\"1234567890\"1234567890\"1234567890\n1234567890\"1234567890\"1234567890\"1234567890\"1234567890\"1234567890\"1234567890\"1234567890\"1234567890\"1234567890\n1234567890\"1234567890\"1234567890\"1234567890\"1234567890\"1234567890\"1234567890\"1234567890\"1234567890\"1234567890\n1234567890\"1234567890\"1234567890\"1234567890\"1234567890\"1234567890\"1234567890\"1234567890\"1234567890\"1234567890\n1234567890\"1234567890\"1234567890\"1234567890\"1234567890\"1234567890\"1234567890\"1234567890\"1234567890\"1234567890\n1234567890\"1234567890\"1234567890\"1234567890\"1234567890\"1234567890\"1234567890\"1234567890\"1234567890\"1234567890\n1234567890\"1234567890\"1234567890\"1234567890\"1234567890\"1234567890\"1234567890\"1234567890\"1234567890\"1234567890\n1234567890\"1234567890\"1234567890\"1234567890\"1234567890\"1234567890\"1234567890\"1234567890\"1234567890\"1234567890"
IO.write(s)
// expect: 1234567890"1234567890"1234567890"1234567890"1234567890"1234567890"1234567890"1234567890"1234567890"1234567890
// expect: 1234567890"1234567890"1234567890"1234567890"1234567890"1234567890"1234567890"1234567890"1234567890"1234567890
// expect: 1234567890"1234567890"1234567890"1234567890"1234567890"1234567890"1234567890"1234567890"1234567890"1234567890
// expect: 1234567890"1234567890"1234567890"1234567890"1234567890"1234567890"1234567890"1234567890"1234567890"1234567890
// expect: 1234567890"1234567890"1234567890"1234567890"1234567890"1234567890"1234567890"1234567890"1234567890"1234567890
// expect: 1234567890"1234567890"1234567890"1234567890"1234567890"1234567890"1234567890"1234567890"1234567890"1234567890
// expect: 1234567890"1234567890"1234567890"1234567890"1234567890"1234567890"1234567890"1234567890"1234567890"1234567890
// expect: 1234567890"1234567890"1234567890"1234567890"1234567890"1234567890"1234567890"1234567890"1234567890"1234567890
// expect: 1234567890"1234567890"1234567890"1234567890"1234567890"1234567890"1234567890"1234567890"1234567890"1234567890
// expect: 1234567890"1234567890"1234567890"1234567890"1234567890"1234567890"1234567890"1234567890"1234567890"1234567890