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Merged
merged 1 commit into from
Jul 22, 2016
Merged

Binary format support for wasm globals #652

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83 changes: 70 additions & 13 deletions src/wasm-binary.h
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Original file line number Diff line number Diff line change
Expand Up @@ -244,19 +244,13 @@ namespace Section {
extern const char* FunctionSignatures;
extern const char* Functions;
extern const char* ExportTable;
extern const char* Globals;
extern const char* DataSegments;
extern const char* FunctionTable;
extern const char* Names;
extern const char* Start;
};

enum FunctionEntry {
Named = 1,
Import = 2,
Locals = 4,
Export = 8
};

enum ASTNodes {
CurrentMemory = 0x3b,
GrowMemory = 0x39,
Expand Down Expand Up @@ -418,6 +412,8 @@ enum ASTNodes {
CallFunction = 0x16,
CallIndirect = 0x17,
CallImport = 0x18,
GetGlobal = 0x1a,
SetGlobal = 0x1b,

Nop = 0x00,
Block = 0x01,
Expand Down Expand Up @@ -486,6 +482,7 @@ class WasmBinaryWriter : public Visitor<WasmBinaryWriter, void> {
writeFunctionSignatures();
writeFunctionTable();
writeMemory();
writeGlobals();
writeExports();
writeStart();
writeFunctions();
Expand Down Expand Up @@ -632,6 +629,12 @@ class WasmBinaryWriter : public Visitor<WasmBinaryWriter, void> {
finishSection(start);
}

void writeExpression(Expression* curr) {
assert(depth == 0);
recurse(curr);
assert(depth == 0);
}

void writeFunctions() {
if (wasm->functions.size() == 0) return;
if (debug) std::cerr << "== writeFunctions" << std::endl;
Expand All @@ -657,9 +660,7 @@ class WasmBinaryWriter : public Visitor<WasmBinaryWriter, void> {
if (numLocalsByType[i64]) o << U32LEB(numLocalsByType[i64]) << binaryWasmType(i64);
if (numLocalsByType[f32]) o << U32LEB(numLocalsByType[f32]) << binaryWasmType(f32);
if (numLocalsByType[f64]) o << U32LEB(numLocalsByType[f64]) << binaryWasmType(f64);
depth = 0;
recurse(function->body);
assert(depth == 0);
writeExpression(function->body);
size_t size = o.size() - start;
assert(size <= std::numeric_limits<uint32_t>::max());
if (debug) std::cerr << "body size: " << size << ", writing at " << sizePos << ", next starts at " << o.size() << std::endl;
Expand All @@ -668,6 +669,20 @@ class WasmBinaryWriter : public Visitor<WasmBinaryWriter, void> {
finishSection(start);
}

void writeGlobals() {
if (wasm->globals.size() == 0) return;
if (debug) std::cerr << "== writeglobals" << std::endl;
auto start = startSection(BinaryConsts::Section::Globals);
o << U32LEB(wasm->globals.size());
for (auto& curr : wasm->globals) {
if (debug) std::cerr << "write one" << std::endl;
o << binaryWasmType(curr->type);
writeExpression(curr->init);
o << int8_t(BinaryConsts::End);
}
finishSection(start);
}

void writeExports() {
if (wasm->exports.size() == 0) return;
if (debug) std::cerr << "== writeexports" << std::endl;
Expand Down Expand Up @@ -797,7 +812,7 @@ class WasmBinaryWriter : public Visitor<WasmBinaryWriter, void> {

// AST writing via visitors

int depth; // only for debugging
int depth = 0; // only for debugging

void recurse(Expression*& curr) {
if (debug) std::cerr << "zz recurse into " << ++depth << " at " << o.size() << std::endl;
Expand Down Expand Up @@ -920,6 +935,15 @@ class WasmBinaryWriter : public Visitor<WasmBinaryWriter, void> {
recurse(curr->value);
o << int8_t(BinaryConsts::SetLocal) << U32LEB(mappedLocals[curr->index]);
}
void visitGetGlobal(GetGlobal *curr) {
if (debug) std::cerr << "zz node: GetGlobal " << (o.size() + 1) << std::endl;
o << int8_t(BinaryConsts::GetGlobal) << U32LEB(curr->index);
}
void visitSetGlobal(SetGlobal *curr) {
if (debug) std::cerr << "zz node: SetGlobal" << std::endl;
recurse(curr->value);
o << int8_t(BinaryConsts::SetGlobal) << U32LEB(curr->index);
}

void emitMemoryAccess(size_t alignment, size_t bytes, uint32_t offset) {
o << U32LEB(Log2(alignment ? alignment : bytes));
Expand Down Expand Up @@ -1230,6 +1254,7 @@ class WasmBinaryBuilder {
else if (match(BinaryConsts::Section::FunctionSignatures)) readFunctionSignatures();
else if (match(BinaryConsts::Section::Functions)) readFunctions();
else if (match(BinaryConsts::Section::ExportTable)) readExports();
else if (match(BinaryConsts::Section::Globals)) readGlobals();
else if (match(BinaryConsts::Section::DataSegments)) readDataSegments();
else if (match(BinaryConsts::Section::FunctionTable)) readFunctionTable();
else if (match(BinaryConsts::Section::Names)) readNames();
Expand Down Expand Up @@ -1519,7 +1544,7 @@ class WasmBinaryBuilder {
// process body
assert(breakStack.empty());
assert(expressionStack.empty());
depth = 0;
assert(depth == 0);
func->body = getMaybeBlock();
assert(depth == 0);
assert(breakStack.empty());
Expand Down Expand Up @@ -1547,6 +1572,23 @@ class WasmBinaryBuilder {
}
}

void readGlobals() {
if (debug) std::cerr << "== readGlobals" << std::endl;
size_t num = getU32LEB();
if (debug) std::cerr << "num: " << num << std::endl;
for (size_t i = 0; i < num; i++) {
if (debug) std::cerr << "read one" << std::endl;
auto curr = new Global;
curr->type = getWasmType();
assert(depth == 0);
processExpressions();
assert(expressionStack.size() == 1);
curr->init = popExpression();
assert(depth == 0);
wasm.addGlobal(curr);
}
}

std::vector<Name> breakStack;

std::vector<Expression*> expressionStack;
Expand Down Expand Up @@ -1643,7 +1685,7 @@ class WasmBinaryBuilder {

// AST reading

int depth; // only for debugging
int depth = 0; // only for debugging

BinaryConsts::ASTNodes readExpression(Expression*& curr) {
if (pos == endOfFunction) {
Expand All @@ -1665,6 +1707,8 @@ class WasmBinaryBuilder {
case BinaryConsts::CallIndirect: visitCallIndirect((curr = allocator.alloc<CallIndirect>())->cast<CallIndirect>()); break;
case BinaryConsts::GetLocal: visitGetLocal((curr = allocator.alloc<GetLocal>())->cast<GetLocal>()); break;
case BinaryConsts::SetLocal: visitSetLocal((curr = allocator.alloc<SetLocal>())->cast<SetLocal>()); break;
case BinaryConsts::GetGlobal: visitGetGlobal((curr = allocator.alloc<GetGlobal>())->cast<GetGlobal>()); break;
case BinaryConsts::SetGlobal: visitSetGlobal((curr = allocator.alloc<SetGlobal>())->cast<SetGlobal>()); break;
case BinaryConsts::Select: visitSelect((curr = allocator.alloc<Select>())->cast<Select>()); break;
case BinaryConsts::Return: visitReturn((curr = allocator.alloc<Return>())->cast<Return>()); break;
case BinaryConsts::Nop: visitNop((curr = allocator.alloc<Nop>())->cast<Nop>()); break;
Expand Down Expand Up @@ -1863,6 +1907,19 @@ class WasmBinaryBuilder {
curr->value = popExpression();
curr->type = curr->value->type;
}
void visitGetGlobal(GetGlobal *curr) {
if (debug) std::cerr << "zz node: GetGlobal " << pos << std::endl;
curr->index = getU32LEB();
assert(curr->index < wasm.globals.size());
curr->type = wasm.globals[curr->index]->type;
}
void visitSetGlobal(SetGlobal *curr) {
if (debug) std::cerr << "zz node: SetGlobal" << std::endl;
curr->index = getU32LEB();
assert(curr->index < wasm.globals.size());
curr->value = popExpression();
curr->type = curr->value->type;
}

void readMemoryAccess(Address& alignment, size_t bytes, Address& offset) {
alignment = Pow2(getU32LEB());
Expand Down
1 change: 1 addition & 0 deletions src/wasm.cpp
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Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -33,6 +33,7 @@ namespace Section {
const char* FunctionSignatures = "function";
const char* Functions = "code";
const char* ExportTable = "export";
const char* Globals = "global";
const char* DataSegments = "data";
const char* FunctionTable = "table";
const char* Names = "name";
Expand Down