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Unified Diff: src/wasm/ast-decoder.cc

Issue 1504713014: Initial import of v8-native WASM. (Closed) Base URL: https://chromium.googlesource.com/v8/v8.git@master
Patch Set: Created 5 years ago
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Index: src/wasm/ast-decoder.cc
diff --git a/src/wasm/ast-decoder.cc b/src/wasm/ast-decoder.cc
new file mode 100644
index 0000000000000000000000000000000000000000..20bdc0868aec119c007bd9573c80cc914284a6ac
--- /dev/null
+++ b/src/wasm/ast-decoder.cc
@@ -0,0 +1,1577 @@
+// Copyright 2015 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "src/base/platform/elapsed-timer.h"
+#include "src/signature.h"
+
+#include "src/flags.h"
+#include "src/handles.h"
+#include "src/zone-containers.h"
+
+#include "src/wasm/ast-decoder.h"
+#include "src/wasm/decoder.h"
+#include "src/wasm/wasm-module.h"
+#include "src/wasm/wasm-opcodes.h"
+
+#include "src/compiler/wasm-compiler.h"
+
+namespace v8 {
+namespace internal {
+namespace wasm {
+
+#if DEBUG
+#define TRACE(...) \
+ do { \
+ if (FLAG_trace_wasm_decoder) PrintF(__VA_ARGS__); \
+ } while (false)
+#else
+#define TRACE(...)
+#endif
+
+// The root of a decoded tree.
+struct Tree {
+ LocalType type; // tree type.
+ uint32_t count; // number of children.
+ const byte* pc; // start of the syntax tree.
+ TFNode* node; // node in the TurboFan graph.
+ Tree* children[1]; // pointers to children.
+
+ WasmOpcode opcode() const { return static_cast<WasmOpcode>(*pc); }
+};
+
+
+// A production represents an incomplete decoded tree in the LR decoder.
+struct Production {
+ Tree* tree; // the root of the syntax tree.
+ int index; // the current index into the children of the tree.
+
+ WasmOpcode opcode() const { return static_cast<WasmOpcode>(*pc()); }
+ const byte* pc() const { return tree->pc; }
+ bool done() const { return index >= tree->count; }
+ Tree* last() const { return index > 0 ? tree->children[index - 1] : nullptr; }
+};
+
+
+// An SsaEnv environment carries the current local variable renaming
+// as well as the current effect and control dependency in the TF graph.
+// It maintains a control state that tracks whether the environment
+// is reachable, has reached a control end, or has been merged.
+struct SsaEnv {
+ enum State { kControlEnd, kUnreachable, kReached, kMerged };
+
+ State state;
+ TFNode* control;
+ TFNode* effect;
+ TFNode** locals;
+
+ bool go() { return state >= kReached; }
+ void Kill(State new_state = kControlEnd) {
+ state = new_state;
+ locals = nullptr;
+ control = nullptr;
+ effect = nullptr;
+ }
+};
+
+
+// An entry in the stack of blocks during decoding.
+struct Block {
+ SsaEnv* ssa_env; // SSA renaming environment.
+ int stack_depth; // production stack depth.
+};
+
+
+// An entry in the stack of ifs during decoding.
+struct IfEnv {
+ SsaEnv* false_env;
+ SsaEnv* merge_env;
+ SsaEnv** case_envs;
+};
+
+
+// Macros that build nodes only if there is a graph and the current SSA
+// environment is reachable from start. This avoids problems with malformed
+// TF graphs when decoding inputs that have unreachable code.
+#define BUILD(func, ...) (build() ? builder_->func(__VA_ARGS__) : nullptr)
+#define BUILD0(func) (build() ? builder_->func() : nullptr)
+
+
+// A shift-reduce-parser strategy for decoding Wasm code that uses an explicit
+// shift-reduce strategy with multiple internal stacks.
+class LR_WasmDecoder : public Decoder {
+ public:
+ LR_WasmDecoder(Zone* zone, TFBuilder* builder)
+ : Decoder(nullptr, nullptr),
+ zone_(zone),
+ builder_(builder),
+ trees_(zone),
+ stack_(zone),
+ blocks_(zone),
+ ifs_(zone) {}
+
+ TreeResult Decode(FunctionEnv* function_env, const byte* base, const byte* pc,
+ const byte* end) {
+ base::ElapsedTimer decode_timer;
+ if (FLAG_trace_wasm_decode_time) {
+ decode_timer.Start();
+ }
+ trees_.clear();
+ stack_.clear();
+ blocks_.clear();
+ ifs_.clear();
+
+ if (end < pc) {
+ error(pc, "function body end < start");
+ return result_;
+ }
+
+ base_ = base;
+ Reset(pc, end);
+ function_env_ = function_env;
+
+ InitSsaEnv();
+ DecodeFunctionBody();
+
+ Tree* tree = nullptr;
+ if (ok()) {
+ if (ssa_env_->go()) {
+ if (stack_.size() > 0) {
+ error(stack_.back().pc(), end, "fell off end of code");
+ }
+ AddImplicitReturnAtEnd();
+ }
+ if (trees_.size() == 0) {
+ if (function_env_->sig->return_count() > 0) {
+ error(start_, "no trees created");
+ }
+ } else {
+ tree = trees_[0];
+ }
+ }
+
+ if (ok()) {
+ if (FLAG_trace_wasm_decode_time) {
+ double ms = decode_timer.Elapsed().InMillisecondsF();
+ PrintF(" - decoding took %0.3f ms\n", ms);
+ }
+ TRACE("wasm-decode ok\n\n");
+ } else {
+ TRACE("wasm-error module+%-6d func+%d: %s\n\n", baserel(error_pc_),
+ startrel(error_pc_), error_msg_.get());
+ }
+ return toResult(tree);
+ }
+
+ private:
+ static const size_t kErrorMsgSize = 128;
+
+ Zone* zone_;
+ TFBuilder* builder_;
+ const byte* base_;
+ TreeResult result_;
+
+ SsaEnv* ssa_env_;
+ FunctionEnv* function_env_;
+
+ ZoneVector<Tree*> trees_;
+ ZoneVector<Production> stack_;
+ ZoneVector<Block> blocks_;
+ ZoneVector<IfEnv> ifs_;
+
+ inline bool build() { return builder_ && ssa_env_->go(); }
+
+ void InitSsaEnv() {
+ FunctionSig* sig = function_env_->sig;
+ int param_count = static_cast<int>(sig->parameter_count());
+ TFNode* start = nullptr;
+ SsaEnv* ssa_env = reinterpret_cast<SsaEnv*>(zone_->New(sizeof(SsaEnv)));
+ size_t size = sizeof(TFNode*) * EnvironmentCount();
+ ssa_env->state = SsaEnv::kReached;
+ ssa_env->locals =
+ size > 0 ? reinterpret_cast<TFNode**>(zone_->New(size)) : nullptr;
+
+ int pos = 0;
+ if (builder_) {
+ start = builder_->Start(param_count + 1);
+ // Initialize parameters.
+ for (int i = 0; i < param_count; i++) {
+ ssa_env->locals[pos++] = builder_->Param(i, sig->GetParam(i));
+ }
+ // Initialize int32 locals.
+ if (function_env_->local_int32_count > 0) {
+ TFNode* zero = builder_->Int32Constant(0);
+ for (uint32_t i = 0; i < function_env_->local_int32_count; i++) {
+ ssa_env->locals[pos++] = zero;
+ }
+ }
+ // Initialize int64 locals.
+ if (function_env_->local_int64_count > 0) {
+ TFNode* zero = builder_->Int64Constant(0);
+ for (uint32_t i = 0; i < function_env_->local_int64_count; i++) {
+ ssa_env->locals[pos++] = zero;
+ }
+ }
+ // Initialize float32 locals.
+ if (function_env_->local_float32_count > 0) {
+ TFNode* zero = builder_->Float32Constant(0);
+ for (uint32_t i = 0; i < function_env_->local_float32_count; i++) {
+ ssa_env->locals[pos++] = zero;
+ }
+ }
+ // Initialize float64 locals.
+ if (function_env_->local_float64_count > 0) {
+ TFNode* zero = builder_->Float64Constant(0);
+ for (uint32_t i = 0; i < function_env_->local_float64_count; i++) {
+ ssa_env->locals[pos++] = zero;
+ }
+ }
+ DCHECK_EQ(function_env_->total_locals, pos);
+ DCHECK_EQ(EnvironmentCount(), pos);
+ builder_->set_module(function_env_->module);
+ }
+ ssa_env->control = start;
+ ssa_env->effect = start;
+ SetEnv("initial", ssa_env);
+ }
+
+ void Leaf(LocalType type, TFNode* node = nullptr) {
+ size_t size = sizeof(Tree);
+ Tree* tree = reinterpret_cast<Tree*>(zone_->New(size));
+ tree->type = type;
+ tree->count = 0;
+ tree->pc = pc_;
+ tree->node = node;
+ tree->children[0] = nullptr;
+ Reduce(tree);
+ }
+
+ void Shift(LocalType type, uint32_t count) {
+ size_t size =
+ sizeof(Tree) + (count == 0 ? 0 : ((count - 1) * sizeof(Tree*)));
+ Tree* tree = reinterpret_cast<Tree*>(zone_->New(size));
+ tree->type = type;
+ tree->count = count;
+ tree->pc = pc_;
+ tree->node = nullptr;
+ for (uint32_t i = 0; i < count; i++) tree->children[i] = nullptr;
+ if (count == 0) {
+ Production p = {tree, 0};
+ Reduce(&p);
+ Reduce(tree);
+ } else {
+ stack_.push_back({tree, 0});
+ }
+ }
+
+ void Reduce(Tree* tree) {
+ while (true) {
+ if (stack_.size() == 0) {
+ trees_.push_back(tree);
+ break;
+ }
+ Production* p = &stack_.back();
+ p->tree->children[p->index++] = tree;
+ Reduce(p);
+ if (p->done()) {
+ tree = p->tree;
+ stack_.pop_back();
+ } else {
+ break;
+ }
+ }
+ }
+
+ char* indentation() {
+ static const int kMaxIndent = 64;
+ static char bytes[kMaxIndent + 1];
+ for (int i = 0; i < kMaxIndent; i++) bytes[i] = ' ';
+ bytes[kMaxIndent] = 0;
+ if (stack_.size() < kMaxIndent / 2) {
+ bytes[stack_.size() * 2] = 0;
+ }
+ return bytes;
+ }
+
+ // Decodes the body of a function, producing reduced trees into {result}.
+ void DecodeFunctionBody() {
+ TRACE("wasm-decode %p...%p (%d bytes) %s\n",
+ reinterpret_cast<const void*>(start_),
+ reinterpret_cast<const void*>(limit_),
+ static_cast<int>(limit_ - start_), builder_ ? "graph building" : "");
+
+ if (pc_ >= limit_) return; // Nothing to do.
+
+ while (true) { // decoding loop.
+ int len = 1;
+ WasmOpcode opcode = static_cast<WasmOpcode>(*pc_);
+ TRACE("wasm-decode module+%-6d %s func+%d: 0x%02x %s\n", baserel(pc_),
+ indentation(), startrel(pc_), opcode,
+ WasmOpcodes::OpcodeName(opcode));
+
+ FunctionSig* sig = WasmOpcodes::Signature(opcode);
+ if (sig) {
+ // A simple expression with a fixed signature.
+ Shift(sig->GetReturn(), static_cast<uint32_t>(sig->parameter_count()));
+ pc_ += len;
+ if (pc_ >= limit_) {
+ // End of code reached or exceeded.
+ if (pc_ > limit_ && ok()) {
+ error("Beyond end of code");
+ }
+ return;
+ }
+ continue; // back to decoding loop.
+ }
+
+ switch (opcode) {
+ case kExprNop:
+ Leaf(kAstStmt);
+ break;
+ case kExprBlock: {
+ int length = Operand<uint8_t>(pc_);
+ if (length < 1) {
+ Leaf(kAstStmt);
+ } else {
+ Shift(kAstEnd, length);
+ // The break environment is the outer environment.
+ SsaEnv* break_env = ssa_env_;
+ PushBlock(break_env);
+ SetEnv("block:start", Steal(break_env));
+ }
+ len = 2;
+ break;
+ }
+ case kExprLoop: {
+ int length = Operand<uint8_t>(pc_);
+ if (length < 1) {
+ Leaf(kAstStmt);
+ } else {
+ Shift(kAstEnd, length);
+ // The break environment is the outer environment.
+ SsaEnv* break_env = ssa_env_;
+ PushBlock(break_env);
+ SsaEnv* cont_env = Steal(break_env);
+ // The continue environment is the inner environment.
+ PrepareForLoop(cont_env);
+ SetEnv("loop:start", Split(cont_env));
+ if (ssa_env_->go()) ssa_env_->state = SsaEnv::kReached;
+ PushBlock(cont_env);
+ blocks_.back().stack_depth = -1; // no production for inner block.
+ }
+ len = 2;
+ break;
+ }
+ case kExprIf:
+ Shift(kAstStmt, 2);
+ break;
+ case kExprIfElse:
+ Shift(kAstEnd, 3); // Result type is typeof(x) in {c ? x : y}.
+ break;
+ case kExprSelect:
+ Shift(kAstStmt, 3); // Result type is typeof(x) in {c ? x : y}.
+ break;
+ case kExprBr: {
+ uint32_t depth = Operand<uint8_t>(pc_);
+ Shift(kAstEnd, 1);
+ if (depth >= blocks_.size()) {
+ error("improperly nested branch");
+ }
+ len = 2;
+ break;
+ }
+ case kExprBrIf: {
+ uint32_t depth = Operand<uint8_t>(pc_);
+ Shift(kAstStmt, 2);
+ if (depth >= blocks_.size()) {
+ error("improperly nested conditional branch");
+ }
+ len = 2;
+ break;
+ }
+ case kExprTableSwitch: {
+ if (!checkAvailable(5)) {
+ error("expected #tableswitch <cases> <table>, fell off end");
+ break;
+ }
+ uint16_t case_count = *reinterpret_cast<const uint16_t*>(pc_ + 1);
+ uint16_t table_count = *reinterpret_cast<const uint16_t*>(pc_ + 3);
+ len = 5 + table_count * 2;
+
+ if (table_count == 0) {
+ error("tableswitch with 0 entries");
+ break;
+ }
+
+ if (!checkAvailable(len)) {
+ error("expected #tableswitch <cases> <table>, fell off end");
+ break;
+ }
+
+ Shift(kAstEnd, 1 + case_count);
+
+ // Verify table.
+ for (int i = 0; i < table_count; i++) {
+ uint16_t target =
+ *reinterpret_cast<const uint16_t*>(pc_ + 5 + i * 2);
+ if (target >= 0x8000) {
+ size_t depth = target - 0x8000;
+ if (depth > blocks_.size()) {
+ error(pc_ + 5 + i * 2, "improper branch in tableswitch");
+ }
+ } else {
+ if (target >= case_count) {
+ error(pc_ + 5 + i * 2, "invalid case target in tableswitch");
+ }
+ }
+ }
+ break;
+ }
+ case kExprReturn: {
+ int count = static_cast<int>(function_env_->sig->return_count());
+ if (count == 0) {
+ BUILD(Return, 0, builder_->Buffer(0));
+ ssa_env_->Kill();
+ Leaf(kAstEnd);
+ } else {
+ Shift(kAstEnd, count);
+ }
+ break;
+ }
+ case kExprUnreachable: {
+ BUILD0(Unreachable);
+ ssa_env_->Kill(SsaEnv::kControlEnd);
+ Leaf(kAstEnd, nullptr);
+ break;
+ }
+ case kExprI8Const: {
+ int32_t value = Operand<int8_t>(pc_);
+ Leaf(kAstI32, BUILD(Int32Constant, value));
+ len = 2;
+ break;
+ }
+ case kExprI32Const: {
+ int32_t value = Operand<int32_t>(pc_);
+ Leaf(kAstI32, BUILD(Int32Constant, value));
+ len = 5;
+ break;
+ }
+ case kExprI64Const: {
+ int64_t value = Operand<int64_t>(pc_);
+ Leaf(kAstI64, BUILD(Int64Constant, value));
+ len = 9;
+ break;
+ }
+ case kExprF32Const: {
+ float value = Operand<float>(pc_);
+ Leaf(kAstF32, BUILD(Float32Constant, value));
+ len = 5;
+ break;
+ }
+ case kExprF64Const: {
+ double value = Operand<double>(pc_);
+ Leaf(kAstF64, BUILD(Float64Constant, value));
+ len = 9;
+ break;
+ }
+ case kExprGetLocal: {
+ uint32_t index;
+ LocalType type = LocalOperand(pc_, &index, &len);
+ TFNode* val =
+ build() && type != kAstStmt ? ssa_env_->locals[index] : nullptr;
+ Leaf(type, val);
+ break;
+ }
+ case kExprSetLocal: {
+ uint32_t index;
+ LocalType type = LocalOperand(pc_, &index, &len);
+ Shift(type, 1);
+ break;
+ }
+ case kExprLoadGlobal: {
+ uint32_t index;
+ LocalType type = GlobalOperand(pc_, &index, &len);
+ Leaf(type, BUILD(LoadGlobal, index));
+ break;
+ }
+ case kExprStoreGlobal: {
+ uint32_t index;
+ LocalType type = GlobalOperand(pc_, &index, &len);
+ Shift(type, 1);
+ break;
+ }
+ case kExprI32LoadMem8S:
+ case kExprI32LoadMem8U:
+ case kExprI32LoadMem16S:
+ case kExprI32LoadMem16U:
+ case kExprI32LoadMem:
+ len = DecodeLoadMem(pc_, kAstI32);
+ break;
+ case kExprI64LoadMem8S:
+ case kExprI64LoadMem8U:
+ case kExprI64LoadMem16S:
+ case kExprI64LoadMem16U:
+ case kExprI64LoadMem32S:
+ case kExprI64LoadMem32U:
+ case kExprI64LoadMem:
+ len = DecodeLoadMem(pc_, kAstI64);
+ break;
+ case kExprF32LoadMem:
+ len = DecodeLoadMem(pc_, kAstF32);
+ break;
+ case kExprF64LoadMem:
+ len = DecodeLoadMem(pc_, kAstF64);
+ break;
+ case kExprI32StoreMem8:
+ case kExprI32StoreMem16:
+ case kExprI32StoreMem:
+ len = DecodeStoreMem(pc_, kAstI32);
+ break;
+ case kExprI64StoreMem8:
+ case kExprI64StoreMem16:
+ case kExprI64StoreMem32:
+ case kExprI64StoreMem:
+ len = DecodeStoreMem(pc_, kAstI64);
+ break;
+ case kExprF32StoreMem:
+ len = DecodeStoreMem(pc_, kAstF32);
+ break;
+ case kExprF64StoreMem:
+ len = DecodeStoreMem(pc_, kAstF64);
+ break;
+ case kExprMemorySize:
+ Leaf(kAstI32, BUILD(MemSize, 0));
+ break;
+ case kExprGrowMemory:
+ Shift(kAstI32, 1);
+ break;
+ case kExprCallFunction: {
+ uint32_t unused;
+ FunctionSig* sig = FunctionSigOperand(pc_, &unused, &len);
+ if (sig) {
+ LocalType type =
+ sig->return_count() == 0 ? kAstStmt : sig->GetReturn();
+ Shift(type, static_cast<int>(sig->parameter_count()));
+ } else {
+ Leaf(kAstI32); // error
+ }
+ break;
+ }
+ case kExprCallIndirect: {
+ uint32_t unused;
+ FunctionSig* sig = SigOperand(pc_, &unused, &len);
+ if (sig) {
+ LocalType type =
+ sig->return_count() == 0 ? kAstStmt : sig->GetReturn();
+ Shift(type, static_cast<int>(1 + sig->parameter_count()));
+ } else {
+ Leaf(kAstI32); // error
+ }
+ break;
+ }
+ default:
+ error("Invalid opcode");
+ return;
+ }
+ pc_ += len;
+ if (pc_ >= limit_) {
+ // End of code reached or exceeded.
+ if (pc_ > limit_ && ok()) {
+ error("Beyond end of code");
+ }
+ return;
+ }
+ }
+ }
+
+ void PushBlock(SsaEnv* ssa_env) {
+ blocks_.push_back({ssa_env, static_cast<int>(stack_.size() - 1)});
+ }
+
+ int DecodeLoadMem(const byte* pc, LocalType type) {
+ int length = 2;
+ uint32_t offset;
+ MemoryAccessOperand(pc, &length, &offset);
+ Shift(type, 1);
+ return length;
+ }
+
+ int DecodeStoreMem(const byte* pc, LocalType type) {
+ int length = 2;
+ uint32_t offset;
+ MemoryAccessOperand(pc, &length, &offset);
+ Shift(type, 2);
+ return length;
+ }
+
+ void AddImplicitReturnAtEnd() {
+ int retcount = static_cast<int>(function_env_->sig->return_count());
+ if (retcount == 0) {
+ BUILD0(ReturnVoid);
+ return;
+ }
+
+ if (trees_.size() < retcount) {
+ error(limit_, nullptr,
+ "ImplicitReturn expects %d arguments, only %d remain", retcount,
+ static_cast<int>(trees_.size()));
+ return;
+ }
+
+ TRACE("wasm-decode implicit return of %d args\n", retcount);
+
+ TFNode** buffer = BUILD(Buffer, retcount);
+ for (int index = 0; index < retcount; index++) {
+ Tree* tree = trees_[trees_.size() - 1 - index];
+ if (buffer) buffer[index] = tree->node;
+ LocalType expected = function_env_->sig->GetReturn(index);
+ if (tree->type != expected) {
+ error(limit_, tree->pc,
+ "ImplicitReturn[%d] expected type %s, found %s of type %s", index,
+ WasmOpcodes::TypeName(expected),
+ WasmOpcodes::OpcodeName(tree->opcode()),
+ WasmOpcodes::TypeName(tree->type));
+ return;
+ }
+ }
+
+ BUILD(Return, retcount, buffer);
+ }
+
+ int baserel(const byte* ptr) {
+ return base_ ? static_cast<int>(ptr - base_) : 0;
+ }
+
+ int startrel(const byte* ptr) { return static_cast<int>(ptr - start_); }
+
+ void Reduce(Production* p) {
+ WasmOpcode opcode = p->opcode();
+ TRACE("-----reduce module+%-6d %s func+%d: 0x%02x %s\n", baserel(p->pc()),
+ indentation(), startrel(p->pc()), opcode,
+ WasmOpcodes::OpcodeName(opcode));
+ FunctionSig* sig = WasmOpcodes::Signature(opcode);
+ if (sig) {
+ // A simple expression with a fixed signature.
+ TypeCheckLast(p, sig->GetParam(p->index - 1));
+ if (p->done() && build()) {
+ if (sig->parameter_count() == 2) {
+ p->tree->node = builder_->Binop(opcode, p->tree->children[0]->node,
+ p->tree->children[1]->node);
+ } else if (sig->parameter_count() == 1) {
+ p->tree->node = builder_->Unop(opcode, p->tree->children[0]->node);
+ } else {
+ UNREACHABLE();
+ }
+ }
+ return;
+ }
+
+ switch (opcode) {
+ case kExprBlock: {
+ if (p->done()) {
+ Block* last = &blocks_.back();
+ DCHECK_EQ(stack_.size() - 1, last->stack_depth);
+ // fallthrough with the last expression.
+ ReduceBreakToExprBlock(p, last);
+ SetEnv("block:end", last->ssa_env);
+ blocks_.pop_back();
+ }
+ break;
+ }
+ case kExprLoop: {
+ if (p->done()) {
+ // Pop the continue environment.
+ blocks_.pop_back();
+ // Get the break environment.
+ Block* last = &blocks_.back();
+ DCHECK_EQ(stack_.size() - 1, last->stack_depth);
+ // fallthrough with the last expression.
+ ReduceBreakToExprBlock(p, last);
+ SetEnv("loop:end", last->ssa_env);
+ blocks_.pop_back();
+ }
+ break;
+ }
+ case kExprIf: {
+ if (p->index == 1) {
+ // Condition done. Split environment for true branch.
+ TypeCheckLast(p, kAstI32);
+ SsaEnv* false_env = ssa_env_;
+ SsaEnv* true_env = Split(ssa_env_);
+ ifs_.push_back({nullptr, false_env, nullptr});
+ BUILD(Branch, p->last()->node, &true_env->control,
+ &false_env->control);
+ SetEnv("if:true", true_env);
+ } else if (p->index == 2) {
+ // True block done. Merge true and false environments.
+ IfEnv* env = &ifs_.back();
+ SsaEnv* merge = env->merge_env;
+ if (merge->go()) {
+ merge->state = SsaEnv::kReached;
+ Goto(ssa_env_, merge);
+ }
+ SetEnv("if:merge", merge);
+ ifs_.pop_back();
+ }
+ break;
+ }
+ case kExprIfElse: {
+ if (p->index == 1) {
+ // Condition done. Split environment for true and false branches.
+ TypeCheckLast(p, kAstI32);
+ SsaEnv* merge_env = ssa_env_;
+ TFNode* if_true = nullptr;
+ TFNode* if_false = nullptr;
+ BUILD(Branch, p->last()->node, &if_true, &if_false);
+ SsaEnv* false_env = Split(ssa_env_);
+ SsaEnv* true_env = Steal(ssa_env_);
+ false_env->control = if_false;
+ true_env->control = if_true;
+ ifs_.push_back({false_env, merge_env, nullptr});
+ SetEnv("if_else:true", true_env);
+ } else if (p->index == 2) {
+ // True expr done.
+ IfEnv* env = &ifs_.back();
+ MergeIntoProduction(p, env->merge_env, p->last());
+ // Switch to environment for false branch.
+ SsaEnv* false_env = ifs_.back().false_env;
+ SetEnv("if_else:false", false_env);
+ } else if (p->index == 3) {
+ // False expr done.
+ IfEnv* env = &ifs_.back();
+ MergeIntoProduction(p, env->merge_env, p->last());
+ SetEnv("if_else:merge", env->merge_env);
+ ifs_.pop_back();
+ }
+ break;
+ }
+ case kExprSelect: {
+ if (p->index == 1) {
+ // Condition done.
+ TypeCheckLast(p, kAstI32);
+ } else if (p->index == 2) {
+ // True expression done.
+ p->tree->type = p->last()->type;
+ if (p->tree->type == kAstStmt) {
+ error(p->pc(), p->tree->children[1]->pc,
+ "select operand should be expression");
+ }
+ } else {
+ // False expression done.
+ DCHECK(p->done());
+ TypeCheckLast(p, p->tree->type);
+ if (build()) {
+ TFNode* controls[2];
+ builder_->Branch(p->tree->children[0]->node, &controls[0],
+ &controls[1]);
+ TFNode* merge = builder_->Merge(2, controls);
+ TFNode* vals[2] = {p->tree->children[1]->node,
+ p->tree->children[2]->node};
+ TFNode* phi = builder_->Phi(p->tree->type, 2, vals, merge);
+ p->tree->node = phi;
+ ssa_env_->control = merge;
+ }
+ }
+ break;
+ }
+ case kExprBr: {
+ uint32_t depth = Operand<uint8_t>(p->pc());
+ if (depth >= blocks_.size()) {
+ error("improperly nested branch");
+ break;
+ }
+ Block* block = &blocks_[blocks_.size() - depth - 1];
+ ReduceBreakToExprBlock(p, block);
+ break;
+ }
+ case kExprBrIf: {
+ if (p->index == 1) {
+ TypeCheckLast(p, kAstI32);
+ } else if (p->done()) {
+ uint32_t depth = Operand<uint8_t>(p->pc());
+ if (depth >= blocks_.size()) {
+ error("improperly nested branch");
+ break;
+ }
+ Block* block = &blocks_[blocks_.size() - depth - 1];
+ SsaEnv* fenv = ssa_env_;
+ SsaEnv* tenv = Split(fenv);
+ BUILD(Branch, p->tree->children[0]->node, &tenv->control,
+ &fenv->control);
+ ssa_env_ = tenv;
+ ReduceBreakToExprBlock(p, block);
+ ssa_env_ = fenv;
+ }
+ break;
+ }
+ case kExprTableSwitch: {
+ uint16_t table_count = *reinterpret_cast<const uint16_t*>(p->pc() + 3);
+ if (table_count == 1) {
+ // Degenerate switch with only a default target.
+ if (p->index == 1) {
+ SsaEnv* break_env = ssa_env_;
+ PushBlock(break_env);
+ SetEnv("switch:default", Steal(break_env));
+ }
+ if (p->done()) {
+ Block* block = &blocks_.back();
+ // fall through to the end.
+ ReduceBreakToExprBlock(p, block);
+ SetEnv("switch:end", block->ssa_env);
+ blocks_.pop_back();
+ }
+ break;
+ }
+
+ if (p->index == 1) {
+ // Switch key finished.
+ TypeCheckLast(p, kAstI32);
+
+ TFNode* sw = BUILD(Switch, table_count, p->last()->node);
+
+ // Allocate environments for each case.
+ uint16_t case_count = *reinterpret_cast<const uint16_t*>(p->pc() + 1);
+ SsaEnv** case_envs = zone_->NewArray<SsaEnv*>(case_count);
+ for (int i = 0; i < case_count; i++) {
+ case_envs[i] = UnreachableEnv();
+ }
+
+ ifs_.push_back({nullptr, nullptr, case_envs});
+ SsaEnv* break_env = ssa_env_;
+ PushBlock(break_env);
+ SsaEnv* copy = Steal(break_env);
+ ssa_env_ = copy;
+
+ // Build the environments for each case based on the table.
+ const uint16_t* table =
+ reinterpret_cast<const uint16_t*>(p->pc() + 5);
+ for (int i = 0; i < table_count; i++) {
+ uint16_t target = table[i];
+ SsaEnv* env = Split(copy);
+ env->control = (i == table_count - 1) ? BUILD(IfDefault, sw)
+ : BUILD(IfValue, i, sw);
+ if (target >= 0x8000) {
+ // Targets an outer block.
+ int depth = target - 0x8000;
+ SsaEnv* tenv = blocks_[blocks_.size() - depth - 1].ssa_env;
+ Goto(env, tenv);
+ } else {
+ // Targets a case.
+ Goto(env, case_envs[target]);
+ }
+ }
+
+ // Switch to the environment for the first case.
+ SetEnv("switch:case", case_envs[0]);
+ } else {
+ // Switch case finished.
+ if (p->done()) {
+ // Last case. Fall through to the end.
+ Block* block = &blocks_.back();
+ ReduceBreakToExprBlock(p, block);
+ SsaEnv* next = block->ssa_env;
+ blocks_.pop_back();
+ ifs_.pop_back();
+ SetEnv("switch:end", next);
+ } else {
+ // Interior case. Maybe fall through to the next case.
+ SsaEnv* next = ifs_.back().case_envs[p->index - 1];
+ if (ssa_env_->go()) Goto(ssa_env_, next);
+ SetEnv("switch:case", next);
+ }
+ }
+ break;
+ }
+ case kExprReturn: {
+ TypeCheckLast(p, function_env_->sig->GetReturn(p->index - 1));
+ if (p->done()) {
+ if (build()) {
+ int count = p->tree->count;
+ TFNode** buffer = builder_->Buffer(count);
+ for (int i = 0; i < count; i++) {
+ buffer[i] = p->tree->children[i]->node;
+ }
+ BUILD(Return, count, buffer);
+ }
+ ssa_env_->Kill(SsaEnv::kControlEnd);
+ }
+ break;
+ }
+ case kExprSetLocal: {
+ int unused = 0;
+ uint32_t index;
+ LocalType type = LocalOperand(p->pc(), &index, &unused);
+ Tree* val = p->last();
+ if (type == val->type) {
+ if (builder_) ssa_env_->locals[index] = val->node;
+ p->tree->node = val->node;
+ } else {
+ error(p->pc(), val->pc, "Typecheck failed in SetLocal");
+ }
+ break;
+ }
+ case kExprStoreGlobal: {
+ int unused = 0;
+ uint32_t index;
+ LocalType type = GlobalOperand(p->pc(), &index, &unused);
+ Tree* val = p->last();
+ if (type == val->type) {
+ BUILD(StoreGlobal, index, val->node);
+ p->tree->node = val->node;
+ } else {
+ error(p->pc(), val->pc, "Typecheck failed in StoreGlobal");
+ }
+ break;
+ }
+
+ case kExprI32LoadMem8S:
+ return ReduceLoadMem(p, kAstI32, MachineType::Int8());
+ case kExprI32LoadMem8U:
+ return ReduceLoadMem(p, kAstI32, MachineType::Uint8());
+ case kExprI32LoadMem16S:
+ return ReduceLoadMem(p, kAstI32, MachineType::Int16());
+ case kExprI32LoadMem16U:
+ return ReduceLoadMem(p, kAstI32, MachineType::Uint16());
+ case kExprI32LoadMem:
+ return ReduceLoadMem(p, kAstI32, MachineType::Int32());
+
+ case kExprI64LoadMem8S:
+ return ReduceLoadMem(p, kAstI64, MachineType::Int8());
+ case kExprI64LoadMem8U:
+ return ReduceLoadMem(p, kAstI64, MachineType::Uint8());
+ case kExprI64LoadMem16S:
+ return ReduceLoadMem(p, kAstI64, MachineType::Int16());
+ case kExprI64LoadMem16U:
+ return ReduceLoadMem(p, kAstI64, MachineType::Uint16());
+ case kExprI64LoadMem32S:
+ return ReduceLoadMem(p, kAstI64, MachineType::Int32());
+ case kExprI64LoadMem32U:
+ return ReduceLoadMem(p, kAstI64, MachineType::Uint32());
+ case kExprI64LoadMem:
+ return ReduceLoadMem(p, kAstI64, MachineType::Int64());
+
+ case kExprF32LoadMem:
+ return ReduceLoadMem(p, kAstF32, MachineType::Float32());
+
+ case kExprF64LoadMem:
+ return ReduceLoadMem(p, kAstF64, MachineType::Float64());
+
+ case kExprI32StoreMem8:
+ return ReduceStoreMem(p, kAstI32, MachineType::Int8());
+ case kExprI32StoreMem16:
+ return ReduceStoreMem(p, kAstI32, MachineType::Int16());
+ case kExprI32StoreMem:
+ return ReduceStoreMem(p, kAstI32, MachineType::Int32());
+
+ case kExprI64StoreMem8:
+ return ReduceStoreMem(p, kAstI64, MachineType::Int8());
+ case kExprI64StoreMem16:
+ return ReduceStoreMem(p, kAstI64, MachineType::Int16());
+ case kExprI64StoreMem32:
+ return ReduceStoreMem(p, kAstI64, MachineType::Int32());
+ case kExprI64StoreMem:
+ return ReduceStoreMem(p, kAstI64, MachineType::Int64());
+
+ case kExprF32StoreMem:
+ return ReduceStoreMem(p, kAstF32, MachineType::Float32());
+
+ case kExprF64StoreMem:
+ return ReduceStoreMem(p, kAstF64, MachineType::Float64());
+
+ case kExprGrowMemory:
+ TypeCheckLast(p, kAstI32);
+ // TODO(titzer): build node for GrowMemory
+ p->tree->node = BUILD(Int32Constant, 0);
+ return;
+
+ case kExprCallFunction: {
+ int len;
+ uint32_t index;
+ FunctionSig* sig = FunctionSigOperand(p->pc(), &index, &len);
+ if (!sig) break;
+ if (p->index > 0) {
+ TypeCheckLast(p, sig->GetParam(p->index - 1));
+ }
+ if (p->done() && build()) {
+ uint32_t count = p->tree->count + 1;
+ TFNode** buffer = builder_->Buffer(count);
+ FunctionSig* sig = FunctionSigOperand(p->pc(), &index, &len);
+ USE(sig);
+ buffer[0] = nullptr; // reserved for code object.
+ for (int i = 1; i < count; i++) {
+ buffer[i] = p->tree->children[i - 1]->node;
+ }
+ p->tree->node = builder_->CallDirect(index, buffer);
+ }
+ break;
+ }
+ case kExprCallIndirect: {
+ int len;
+ uint32_t index;
+ FunctionSig* sig = SigOperand(p->pc(), &index, &len);
+ if (p->index == 1) {
+ TypeCheckLast(p, kAstI32);
+ } else {
+ TypeCheckLast(p, sig->GetParam(p->index - 2));
+ }
+ if (p->done() && build()) {
+ uint32_t count = p->tree->count;
+ TFNode** buffer = builder_->Buffer(count);
+ for (int i = 0; i < count; i++) {
+ buffer[i] = p->tree->children[i]->node;
+ }
+ p->tree->node = builder_->CallIndirect(index, buffer);
+ }
+ break;
+ }
+ default:
+ break;
+ }
+ }
+
+ void ReduceBreakToExprBlock(Production* p, Block* block) {
+ if (block->stack_depth < 0) {
+ // This is the inner loop block, which does not have a value.
+ Goto(ssa_env_, block->ssa_env);
+ } else {
+ // Merge the value into the production for the block.
+ Production* bp = &stack_[block->stack_depth];
+ MergeIntoProduction(bp, block->ssa_env, p->last());
+ }
+ }
+
+ void MergeIntoProduction(Production* p, SsaEnv* target, Tree* expr) {
+ if (!ssa_env_->go()) return;
+
+ bool first = target->state == SsaEnv::kUnreachable;
+ Goto(ssa_env_, target);
+ if (expr->type == kAstEnd) return;
+
+ if (first) {
+ // first merge to this environment; set the type and the node.
+ p->tree->type = expr->type;
+ p->tree->node = expr->node;
+ } else {
+ // merge with the existing value for this block.
+ LocalType type = p->tree->type;
+ if (expr->type != type) {
+ type = kAstStmt;
+ p->tree->type = kAstStmt;
+ p->tree->node = nullptr;
+ } else if (type != kAstStmt) {
+ p->tree->node = CreateOrMergeIntoPhi(type, target->control,
+ p->tree->node, expr->node);
+ }
+ }
+ }
+
+ void ReduceLoadMem(Production* p, LocalType type, MachineType mem_type) {
+ DCHECK_EQ(1, p->index);
+ TypeCheckLast(p, kAstI32); // index
+ if (build()) {
+ int length = 0;
+ uint32_t offset = 0;
+ MemoryAccessOperand(p->pc(), &length, &offset);
+ p->tree->node =
+ builder_->LoadMem(type, mem_type, p->last()->node, offset);
+ }
+ }
+
+ void ReduceStoreMem(Production* p, LocalType type, MachineType mem_type) {
+ if (p->index == 1) {
+ TypeCheckLast(p, kAstI32); // index
+ } else {
+ DCHECK_EQ(2, p->index);
+ TypeCheckLast(p, type);
+ if (build()) {
+ int length = 0;
+ uint32_t offset = 0;
+ MemoryAccessOperand(p->pc(), &length, &offset);
+ TFNode* val = p->tree->children[1]->node;
+ builder_->StoreMem(mem_type, p->tree->children[0]->node, offset, val);
+ p->tree->node = val;
+ }
+ }
+ }
+
+ void TypeCheckLast(Production* p, LocalType expected) {
+ LocalType result = p->last()->type;
+ if (result == expected) return;
+ if (result == kAstEnd) return;
+ if (expected != kAstStmt) {
+ error(p->pc(), p->last()->pc,
+ "%s[%d] expected type %s, found %s of type %s",
+ WasmOpcodes::OpcodeName(p->opcode()), p->index - 1,
+ WasmOpcodes::TypeName(expected),
+ WasmOpcodes::OpcodeName(p->last()->opcode()),
+ WasmOpcodes::TypeName(p->last()->type));
+ }
+ }
+
+ void SetEnv(const char* reason, SsaEnv* env) {
+ TRACE(" env = %p, block depth = %d, reason = %s", static_cast<void*>(env),
+ static_cast<int>(blocks_.size()), reason);
+ if (env->control != nullptr && FLAG_trace_wasm_decoder) {
+ TRACE(", control = ");
+ compiler::WasmGraphBuilder::PrintDebugName(env->control);
+ }
+ TRACE("\n");
+ ssa_env_ = env;
+ if (builder_) {
+ builder_->set_control_ptr(&env->control);
+ builder_->set_effect_ptr(&env->effect);
+ }
+ }
+
+ void Goto(SsaEnv* from, SsaEnv* to) {
+ DCHECK_NOT_NULL(to);
+ if (!from->go()) return;
+ switch (to->state) {
+ case SsaEnv::kUnreachable: { // Overwrite destination.
+ to->state = SsaEnv::kReached;
+ to->locals = from->locals;
+ to->control = from->control;
+ to->effect = from->effect;
+ break;
+ }
+ case SsaEnv::kReached: { // Create a new merge.
+ to->state = SsaEnv::kMerged;
+ if (!builder_) break;
+ // Merge control.
+ TFNode* controls[] = {to->control, from->control};
+ TFNode* merge = builder_->Merge(2, controls);
+ to->control = merge;
+ // Merge effects.
+ if (from->effect != to->effect) {
+ TFNode* effects[] = {to->effect, from->effect, merge};
+ to->effect = builder_->EffectPhi(2, effects, merge);
+ }
+ // Merge SSA values.
+ for (int i = EnvironmentCount() - 1; i >= 0; i--) {
+ TFNode* a = to->locals[i];
+ TFNode* b = from->locals[i];
+ if (a != b) {
+ TFNode* vals[] = {a, b};
+ to->locals[i] =
+ builder_->Phi(function_env_->GetLocalType(i), 2, vals, merge);
+ }
+ }
+ break;
+ }
+ case SsaEnv::kMerged: {
+ if (!builder_) break;
+ TFNode* merge = to->control;
+ // Extend the existing merge.
+ builder_->AppendToMerge(merge, from->control);
+ // Merge effects.
+ if (builder_->IsPhiWithMerge(to->effect, merge)) {
+ builder_->AppendToPhi(merge, to->effect, from->effect);
+ } else if (to->effect != from->effect) {
+ uint32_t count = builder_->InputCount(merge);
+ TFNode** effects = builder_->Buffer(count);
+ for (int j = 0; j < count - 1; j++) effects[j] = to->effect;
+ effects[count - 1] = from->effect;
+ to->effect = builder_->EffectPhi(count, effects, merge);
+ }
+ // Merge locals.
+ for (int i = EnvironmentCount() - 1; i >= 0; i--) {
+ TFNode* tnode = to->locals[i];
+ TFNode* fnode = from->locals[i];
+ if (builder_->IsPhiWithMerge(tnode, merge)) {
+ builder_->AppendToPhi(merge, tnode, fnode);
+ } else if (tnode != fnode) {
+ uint32_t count = builder_->InputCount(merge);
+ TFNode** vals = builder_->Buffer(count);
+ for (int j = 0; j < count - 1; j++) vals[j] = tnode;
+ vals[count - 1] = fnode;
+ to->locals[i] = builder_->Phi(function_env_->GetLocalType(i), count,
+ vals, merge);
+ }
+ }
+ break;
+ }
+ default:
+ UNREACHABLE();
+ }
+ return from->Kill();
+ }
+
+ TFNode* CreateOrMergeIntoPhi(LocalType type, TFNode* merge, TFNode* tnode,
+ TFNode* fnode) {
+ if (builder_->IsPhiWithMerge(tnode, merge)) {
+ builder_->AppendToPhi(merge, tnode, fnode);
+ } else if (tnode != fnode) {
+ uint32_t count = builder_->InputCount(merge);
+ TFNode** vals = builder_->Buffer(count);
+ for (int j = 0; j < count - 1; j++) vals[j] = tnode;
+ vals[count - 1] = fnode;
+ return builder_->Phi(type, count, vals, merge);
+ }
+ return tnode;
+ }
+
+ void BuildInfiniteLoop() {
+ if (ssa_env_->go()) {
+ PrepareForLoop(ssa_env_);
+ SsaEnv* cont_env = ssa_env_;
+ ssa_env_ = Split(ssa_env_);
+ ssa_env_->state = SsaEnv::kReached;
+ Goto(ssa_env_, cont_env);
+ }
+ }
+
+ void PrepareForLoop(SsaEnv* env) {
+ if (env->go()) {
+ env->state = SsaEnv::kMerged;
+ if (builder_) {
+ env->control = builder_->Loop(env->control);
+ env->effect = builder_->EffectPhi(1, &env->effect, env->control);
+ builder_->Terminate(env->effect, env->control);
+ for (int i = EnvironmentCount() - 1; i >= 0; i--) {
+ env->locals[i] = builder_->Phi(function_env_->GetLocalType(i), 1,
+ &env->locals[i], env->control);
+ }
+ }
+ }
+ }
+
+ // Create a complete copy of the {from}.
+ SsaEnv* Split(SsaEnv* from) {
+ DCHECK_NOT_NULL(from);
+ SsaEnv* result = reinterpret_cast<SsaEnv*>(zone_->New(sizeof(SsaEnv)));
+ size_t size = sizeof(TFNode*) * EnvironmentCount();
+ result->control = from->control;
+ result->effect = from->effect;
+ result->state = from->state == SsaEnv::kUnreachable ? SsaEnv::kUnreachable
+ : SsaEnv::kReached;
+
+ if (from->go()) {
+ result->state = SsaEnv::kReached;
+ result->locals =
+ size > 0 ? reinterpret_cast<TFNode**>(zone_->New(size)) : nullptr;
+ memcpy(result->locals, from->locals, size);
+ } else {
+ result->state = SsaEnv::kUnreachable;
+ result->locals = nullptr;
+ }
+
+ return result;
+ }
+
+ // Create a copy of {from} that steals its state and leaves {from}
+ // unreachable.
+ SsaEnv* Steal(SsaEnv* from) {
+ DCHECK_NOT_NULL(from);
+ if (!from->go()) return UnreachableEnv();
+ SsaEnv* result = reinterpret_cast<SsaEnv*>(zone_->New(sizeof(SsaEnv)));
+ result->state = SsaEnv::kReached;
+ result->locals = from->locals;
+ result->control = from->control;
+ result->effect = from->effect;
+ from->Kill(SsaEnv::kUnreachable);
+ return result;
+ }
+
+ // Create an unreachable environment.
+ SsaEnv* UnreachableEnv() {
+ SsaEnv* result = reinterpret_cast<SsaEnv*>(zone_->New(sizeof(SsaEnv)));
+ result->state = SsaEnv::kUnreachable;
+ result->control = nullptr;
+ result->effect = nullptr;
+ result->locals = nullptr;
+ return result;
+ }
+
+ // Load an operand at [pc + 1].
+ template <typename V>
+ V Operand(const byte* pc) {
+ if ((limit_ - pc) < static_cast<int>(1 + sizeof(V))) {
+ const char* msg = "Expected operand following opcode";
+ switch (sizeof(V)) {
+ case 1:
+ msg = "Expected 1-byte operand following opcode";
+ break;
+ case 2:
+ msg = "Expected 2-byte operand following opcode";
+ break;
+ case 4:
+ msg = "Expected 4-byte operand following opcode";
+ break;
+ default:
+ break;
+ }
+ error(pc, msg);
+ return -1;
+ }
+ return *reinterpret_cast<const V*>(pc + 1);
+ }
+
+ int EnvironmentCount() {
+ if (builder_) return static_cast<int>(function_env_->GetLocalCount());
+ return 0; // if we aren't building a graph, don't bother with SSA renaming.
+ }
+
+ LocalType LocalOperand(const byte* pc, uint32_t* index, int* length) {
+ *index = UnsignedLEB128Operand(pc, length);
+ if (function_env_->IsValidLocal(*index)) {
+ return function_env_->GetLocalType(*index);
+ }
+ error(pc, "invalid local variable index");
+ return kAstStmt;
+ }
+
+ LocalType GlobalOperand(const byte* pc, uint32_t* index, int* length) {
+ *index = UnsignedLEB128Operand(pc, length);
+ if (function_env_->module->IsValidGlobal(*index)) {
+ return WasmOpcodes::LocalTypeFor(
+ function_env_->module->GetGlobalType(*index));
+ }
+ error(pc, "invalid global variable index");
+ return kAstStmt;
+ }
+
+ FunctionSig* FunctionSigOperand(const byte* pc, uint32_t* index,
+ int* length) {
+ *index = UnsignedLEB128Operand(pc, length);
+ if (function_env_->module->IsValidFunction(*index)) {
+ return function_env_->module->GetFunctionSignature(*index);
+ }
+ error(pc, "invalid function index");
+ return nullptr;
+ }
+
+ FunctionSig* SigOperand(const byte* pc, uint32_t* index, int* length) {
+ *index = UnsignedLEB128Operand(pc, length);
+ if (function_env_->module->IsValidSignature(*index)) {
+ return function_env_->module->GetSignature(*index);
+ }
+ error(pc, "invalid signature index");
+ return nullptr;
+ }
+
+ uint32_t UnsignedLEB128Operand(const byte* pc, int* length) {
+ uint32_t result = 0;
+ ReadUnsignedLEB128ErrorCode error_code =
+ ReadUnsignedLEB128Operand(pc + 1, limit_, length, &result);
+ if (error_code == kInvalidLEB128) error(pc, "invalid LEB128 varint");
+ if (error_code == kMissingLEB128) error(pc, "expected LEB128 varint");
+ (*length)++;
+ return result;
+ }
+
+ void MemoryAccessOperand(const byte* pc, int* length, uint32_t* offset) {
+ byte bitfield = Operand<uint8_t>(pc);
+ if (MemoryAccess::OffsetField::decode(bitfield)) {
+ *offset = UnsignedLEB128Operand(pc + 1, length);
+ (*length)++; // to account for the memory access byte
+ } else {
+ *offset = 0;
+ *length = 2;
+ }
+ }
+
+ virtual void onFirstError() {
+ limit_ = start_; // Terminate decoding loop.
+ builder_ = nullptr; // Don't build any more nodes.
+#if DEBUG
+ PrintStackForDebugging();
+#endif
+ }
+
+#if DEBUG
+ void PrintStackForDebugging() { PrintProduction(0); }
+
+ void PrintProduction(size_t depth) {
+ if (depth >= stack_.size()) return;
+ Production* p = &stack_[depth];
+ for (size_t d = 0; d < depth; d++) PrintF(" ");
+
+ PrintF("@%d %s [%d]\n", static_cast<int>(p->tree->pc - start_),
+ WasmOpcodes::OpcodeName(p->opcode()), p->tree->count);
+ for (int i = 0; i < p->index; i++) {
+ Tree* child = p->tree->children[i];
+ for (size_t d = 0; d <= depth; d++) PrintF(" ");
+ PrintF("@%d %s [%d]", static_cast<int>(child->pc - start_),
+ WasmOpcodes::OpcodeName(child->opcode()), child->count);
+ if (child->node) {
+ PrintF(" => TF");
+ compiler::WasmGraphBuilder::PrintDebugName(child->node);
+ }
+ PrintF("\n");
+ }
+ PrintProduction(depth + 1);
+ }
+#endif
+};
+
+
+TreeResult VerifyWasmCode(FunctionEnv* env, const byte* base, const byte* start,
+ const byte* end) {
+ Zone zone;
+ LR_WasmDecoder decoder(&zone, nullptr);
+ TreeResult result = decoder.Decode(env, base, start, end);
+ return result;
+}
+
+
+TreeResult BuildTFGraph(TFBuilder* builder, FunctionEnv* env, const byte* base,
+ const byte* start, const byte* end) {
+ Zone zone;
+ LR_WasmDecoder decoder(&zone, builder);
+ TreeResult result = decoder.Decode(env, base, start, end);
+ return result;
+}
+
+
+std::ostream& operator<<(std::ostream& os, const Tree& tree) {
+ if (tree.pc == nullptr) {
+ os << "null";
+ return os;
+ }
+ PrintF("%s", WasmOpcodes::OpcodeName(tree.opcode()));
+ if (tree.count > 0) os << "(";
+ for (int i = 0; i < tree.count; i++) {
+ if (i > 0) os << ", ";
+ os << *tree.children[i];
+ }
+ if (tree.count > 0) os << ")";
+ return os;
+}
+
+
+ReadUnsignedLEB128ErrorCode ReadUnsignedLEB128Operand(const byte* pc,
+ const byte* limit,
+ int* length,
+ uint32_t* result) {
+ *result = 0;
+ const byte* ptr = pc;
+ const byte* end = pc + 5; // maximum 5 bytes.
+ if (end > limit) end = limit;
+ int shift = 0;
+ byte b = 0;
+ while (ptr < end) {
+ b = *ptr++;
+ *result = *result | ((b & 0x7F) << shift);
+ if ((b & 0x80) == 0) break;
+ shift += 7;
+ }
+ DCHECK_LE(ptr - pc, 5);
+ *length = static_cast<int>(ptr - pc);
+ if (ptr == end && (b & 0x80)) {
+ return kInvalidLEB128;
+ } else if (*length == 0) {
+ return kMissingLEB128;
+ } else {
+ return kNoError;
+ }
+}
+
+
+int OpcodeLength(const byte* pc) {
+ switch (static_cast<WasmOpcode>(*pc)) {
+#define DECLARE_OPCODE_CASE(name, opcode, sig) case kExpr##name:
+ FOREACH_LOAD_MEM_OPCODE(DECLARE_OPCODE_CASE)
+ FOREACH_STORE_MEM_OPCODE(DECLARE_OPCODE_CASE)
+#undef DECLARE_OPCODE_CASE
+
+ case kExprI8Const:
+ case kExprBlock:
+ case kExprLoop:
+ case kExprBr:
+ case kExprBrIf:
+ return 2;
+ case kExprI32Const:
+ case kExprF32Const:
+ return 5;
+ case kExprI64Const:
+ case kExprF64Const:
+ return 9;
+ case kExprStoreGlobal:
+ case kExprSetLocal:
+ case kExprLoadGlobal:
+ case kExprCallFunction:
+ case kExprCallIndirect:
+ case kExprGetLocal: {
+ int length;
+ uint32_t result = 0;
+ ReadUnsignedLEB128Operand(pc + 1, pc + 6, &length, &result);
+ return 1 + length;
+ }
+ case kExprTableSwitch: {
+ uint16_t table_count = *reinterpret_cast<const uint16_t*>(pc + 3);
+ return 5 + table_count * 2;
+ }
+
+ default:
+ return 1;
+ }
+}
+
+
+int OpcodeArity(FunctionEnv* env, const byte* pc) {
+#define DECLARE_ARITY(name, ...) \
+ static const LocalType kTypes_##name[] = {__VA_ARGS__}; \
+ static const int kArity_##name = \
+ static_cast<int>(arraysize(kTypes_##name) - 1);
+
+ FOREACH_SIGNATURE(DECLARE_ARITY);
+#undef DECLARE_ARITY
+
+ switch (static_cast<WasmOpcode>(*pc)) {
+ case kExprI8Const:
+ case kExprI32Const:
+ case kExprI64Const:
+ case kExprF64Const:
+ case kExprF32Const:
+ case kExprGetLocal:
+ case kExprLoadGlobal:
+ case kExprNop:
+ case kExprUnreachable:
+ return 0;
+
+ case kExprBr:
+ case kExprStoreGlobal:
+ case kExprSetLocal:
+ return 1;
+
+ case kExprIf:
+ case kExprBrIf:
+ return 2;
+ case kExprIfElse:
+ case kExprSelect:
+ return 3;
+ case kExprBlock:
+ case kExprLoop:
+ return *(pc + 1);
+
+ case kExprCallFunction: {
+ int index = *(pc + 1);
+ return static_cast<int>(
+ env->module->GetFunctionSignature(index)->parameter_count());
+ }
+ case kExprCallIndirect: {
+ int index = *(pc + 1);
+ return 1 + static_cast<int>(
+ env->module->GetSignature(index)->parameter_count());
+ }
+ case kExprReturn:
+ return static_cast<int>(env->sig->return_count());
+ case kExprTableSwitch: {
+ uint16_t case_count = *reinterpret_cast<const uint16_t*>(pc + 1);
+ return 1 + case_count;
+ }
+
+#define DECLARE_OPCODE_CASE(name, opcode, sig) \
+ case kExpr##name: \
+ return kArity_##sig;
+
+ FOREACH_LOAD_MEM_OPCODE(DECLARE_OPCODE_CASE)
+ FOREACH_STORE_MEM_OPCODE(DECLARE_OPCODE_CASE)
+ FOREACH_MISC_MEM_OPCODE(DECLARE_OPCODE_CASE)
+ FOREACH_SIMPLE_OPCODE(DECLARE_OPCODE_CASE)
+#undef DECLARE_OPCODE_CASE
+ }
+}
+} // namespace wasm
+} // namespace internal
+} // namespace v8
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