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// Copyright 2018 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/wasm/graph-builder-interface.h"
#include "src/compiler/wasm-compiler.h"
#include "src/flags/flags.h"
#include "src/handles/handles.h"
#include "src/objects/objects-inl.h"
#include "src/utils/ostreams.h"
#include "src/wasm/decoder.h"
#include "src/wasm/function-body-decoder-impl.h"
#include "src/wasm/function-body-decoder.h"
#include "src/wasm/wasm-limits.h"
#include "src/wasm/wasm-linkage.h"
#include "src/wasm/wasm-module.h"
#include "src/wasm/wasm-opcodes.h"
namespace v8 {
namespace internal {
namespace wasm {
namespace {
// 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;
compiler::WasmInstanceCacheNodes instance_cache;
TFNode** locals;
void Kill(State new_state = kControlEnd) {
state = new_state;
locals = nullptr;
control = nullptr;
effect = nullptr;
instance_cache = {};
}
void SetNotMerged() {
if (state == kMerged) state = kReached;
}
};
#define BUILD(func, ...) \
([&] { \
DCHECK(decoder->ok()); \
return CheckForException(decoder, builder_->func(__VA_ARGS__)); \
})()
constexpr uint32_t kNullCatch = static_cast<uint32_t>(-1);
class WasmGraphBuildingInterface {
public:
static constexpr Decoder::ValidateFlag validate = Decoder::kValidate;
using FullDecoder = WasmFullDecoder<validate, WasmGraphBuildingInterface>;
struct Value : public ValueBase {
TFNode* node = nullptr;
template <typename... Args>
explicit Value(Args&&... args) V8_NOEXCEPT
: ValueBase(std::forward<Args>(args)...) {}
};
struct TryInfo : public ZoneObject {
SsaEnv* catch_env;
TFNode* exception = nullptr;
bool might_throw() const { return exception != nullptr; }
MOVE_ONLY_NO_DEFAULT_CONSTRUCTOR(TryInfo);
explicit TryInfo(SsaEnv* c) : catch_env(c) {}
};
struct Control : public ControlBase<Value> {
SsaEnv* end_env = nullptr; // end environment for the construct.
SsaEnv* false_env = nullptr; // false environment (only for if).
TryInfo* try_info = nullptr; // information about try statements.
int32_t previous_catch = -1; // previous Control with a catch.
MOVE_ONLY_NO_DEFAULT_CONSTRUCTOR(Control);
template <typename... Args>
explicit Control(Args&&... args) V8_NOEXCEPT
: ControlBase(std::forward<Args>(args)...) {}
};
explicit WasmGraphBuildingInterface(compiler::WasmGraphBuilder* builder)
: builder_(builder) {}
void StartFunction(FullDecoder* decoder) {
SsaEnv* ssa_env =
reinterpret_cast<SsaEnv*>(decoder->zone()->New(sizeof(SsaEnv)));
uint32_t num_locals = decoder->num_locals();
uint32_t env_count = num_locals;
size_t size = sizeof(TFNode*) * env_count;
ssa_env->state = SsaEnv::kReached;
ssa_env->locals =
size > 0 ? reinterpret_cast<TFNode**>(decoder->zone()->New(size))
: nullptr;
// The first '+ 1' is needed by TF Start node, the second '+ 1' is for the
// instance parameter.
TFNode* start = builder_->Start(
static_cast<int>(decoder->sig_->parameter_count() + 1 + 1));
ssa_env->effect = start;
ssa_env->control = start;
// Initialize effect and control before initializing the locals default
// values (which might require instance loads) or loading the context.
builder_->set_effect_ptr(&ssa_env->effect);
builder_->set_control_ptr(&ssa_env->control);
// Initialize the instance parameter (index 0).
builder_->set_instance_node(builder_->Param(kWasmInstanceParameterIndex));
// Initialize local variables. Parameters are shifted by 1 because of the
// the instance parameter.
uint32_t index = 0;
for (; index < decoder->sig_->parameter_count(); ++index) {
ssa_env->locals[index] = builder_->Param(index + 1);
}
while (index < num_locals) {
ValueType type = decoder->GetLocalType(index);
TFNode* node = DefaultValue(type);
while (index < num_locals && decoder->GetLocalType(index) == type) {
// Do a whole run of like-typed locals at a time.
ssa_env->locals[index++] = node;
}
}
LoadContextIntoSsa(ssa_env);
SetEnv(ssa_env);
}
// Reload the instance cache entries into the Ssa Environment.
void LoadContextIntoSsa(SsaEnv* ssa_env) {
if (ssa_env) builder_->InitInstanceCache(&ssa_env->instance_cache);
}
void StartFunctionBody(FullDecoder* decoder, Control* block) {}
void FinishFunction(FullDecoder*) { builder_->PatchInStackCheckIfNeeded(); }
void OnFirstError(FullDecoder*) {}
void NextInstruction(FullDecoder*, WasmOpcode) {}
void Block(FullDecoder* decoder, Control* block) {
// The branch environment is the outer environment.
block->end_env = ssa_env_;
SetEnv(Steal(decoder->zone(), ssa_env_));
}
void Loop(FullDecoder* decoder, Control* block) {
SsaEnv* finish_try_env = Steal(decoder->zone(), ssa_env_);
block->end_env = finish_try_env;
// The continue environment is the inner environment.
SetEnv(PrepareForLoop(decoder, finish_try_env));
ssa_env_->SetNotMerged();
if (!decoder->ok()) return;
// Wrap input merge into phis.
for (uint32_t i = 0; i < block->start_merge.arity; ++i) {
Value& val = block->start_merge[i];
val.node = builder_->Phi(val.type, 1, &val.node, block->end_env->control);
}
}
void Try(FullDecoder* decoder, Control* block) {
SsaEnv* outer_env = ssa_env_;
SsaEnv* catch_env = Split(decoder, outer_env);
// Mark catch environment as unreachable, since only accessable
// through catch unwinding (i.e. landing pads).
catch_env->state = SsaEnv::kUnreachable;
SsaEnv* try_env = Steal(decoder->zone(), outer_env);
SetEnv(try_env);
TryInfo* try_info = new (decoder->zone()) TryInfo(catch_env);
block->end_env = outer_env;
block->try_info = try_info;
block->previous_catch = current_catch_;
current_catch_ = static_cast<int32_t>(decoder->control_depth() - 1);
}
void If(FullDecoder* decoder, const Value& cond, Control* if_block) {
TFNode* if_true = nullptr;
TFNode* if_false = nullptr;
BUILD(BranchNoHint, cond.node, &if_true, &if_false);
SsaEnv* end_env = ssa_env_;
SsaEnv* false_env = Split(decoder, ssa_env_);
false_env->control = if_false;
SsaEnv* true_env = Steal(decoder->zone(), ssa_env_);
true_env->control = if_true;
if_block->end_env = end_env;
if_block->false_env = false_env;
SetEnv(true_env);
}
void FallThruTo(FullDecoder* decoder, Control* c) {
DCHECK(!c->is_loop());
MergeValuesInto(decoder, c, &c->end_merge);
}
void PopControl(FullDecoder* decoder, Control* block) {
// A loop just continues with the end environment. There is no merge.
if (block->is_loop()) return;
// Any other block falls through to the parent block.
if (block->reachable()) FallThruTo(decoder, block);
if (block->is_onearmed_if()) {
// Merge the else branch into the end merge.
SetEnv(block->false_env);
MergeValuesInto(decoder, block, &block->end_merge);
}
// Now continue with the merged environment.
SetEnv(block->end_env);
}
void EndControl(FullDecoder* decoder, Control* block) { ssa_env_->Kill(); }
void UnOp(FullDecoder* decoder, WasmOpcode opcode, const Value& value,
Value* result) {
result->node = BUILD(Unop, opcode, value.node, decoder->position());
}
void BinOp(FullDecoder* decoder, WasmOpcode opcode, const Value& lhs,
const Value& rhs, Value* result) {
auto node = BUILD(Binop, opcode, lhs.node, rhs.node, decoder->position());
if (result) result->node = node;
}
void I32Const(FullDecoder* decoder, Value* result, int32_t value) {
result->node = builder_->Int32Constant(value);
}
void I64Const(FullDecoder* decoder, Value* result, int64_t value) {
result->node = builder_->Int64Constant(value);
}
void F32Const(FullDecoder* decoder, Value* result, float value) {
result->node = builder_->Float32Constant(value);
}
void F64Const(FullDecoder* decoder, Value* result, double value) {
result->node = builder_->Float64Constant(value);
}
void RefNull(FullDecoder* decoder, Value* result) {
result->node = builder_->RefNull();
}
void RefFunc(FullDecoder* decoder, uint32_t function_index, Value* result) {
result->node = BUILD(RefFunc, function_index);
}
void Drop(FullDecoder* decoder, const Value& value) {}
void DoReturn(FullDecoder* decoder, Vector<Value> values) {
Vector<TFNode*> nodes = GetNodes(values);
BUILD(Return, nodes);
}
void GetLocal(FullDecoder* decoder, Value* result,
const LocalIndexImmediate<validate>& imm) {
if (!ssa_env_->locals) return; // unreachable
result->node = ssa_env_->locals[imm.index];
}
void SetLocal(FullDecoder* decoder, const Value& value,
const LocalIndexImmediate<validate>& imm) {
if (!ssa_env_->locals) return; // unreachable
ssa_env_->locals[imm.index] = value.node;
}
void TeeLocal(FullDecoder* decoder, const Value& value, Value* result,
const LocalIndexImmediate<validate>& imm) {
result->node = value.node;
if (!ssa_env_->locals) return; // unreachable
ssa_env_->locals[imm.index] = value.node;
}
void GetGlobal(FullDecoder* decoder, Value* result,
const GlobalIndexImmediate<validate>& imm) {
result->node = BUILD(GetGlobal, imm.index);
}
void SetGlobal(FullDecoder* decoder, const Value& value,
const GlobalIndexImmediate<validate>& imm) {
BUILD(SetGlobal, imm.index, value.node);
}
void TableGet(FullDecoder* decoder, const Value& index, Value* result,
const TableIndexImmediate<validate>& imm) {
result->node = BUILD(TableGet, imm.index, index.node, decoder->position());
}
void TableSet(FullDecoder* decoder, const Value& index, const Value& value,
const TableIndexImmediate<validate>& imm) {
BUILD(TableSet, imm.index, index.node, value.node, decoder->position());
}
void Unreachable(FullDecoder* decoder) {
BUILD(Unreachable, decoder->position());
}
void Select(FullDecoder* decoder, const Value& cond, const Value& fval,
const Value& tval, Value* result) {
TFNode* controls[2];
BUILD(BranchNoHint, cond.node, &controls[0], &controls[1]);
TFNode* merge = BUILD(Merge, 2, controls);
TFNode* vals[2] = {tval.node, fval.node};
TFNode* phi = BUILD(Phi, tval.type, 2, vals, merge);
result->node = phi;
ssa_env_->control = merge;
}
void BrOrRet(FullDecoder* decoder, uint32_t depth) {
if (depth == decoder->control_depth() - 1) {
uint32_t ret_count = static_cast<uint32_t>(decoder->sig_->return_count());
Vector<TFNode*> values =
ret_count == 0 ? Vector<TFNode*>{}
: GetNodes(decoder->stack_value(ret_count), ret_count);
BUILD(Return, values);
} else {
Br(decoder, decoder->control_at(depth));
}
}
void Br(FullDecoder* decoder, Control* target) {
MergeValuesInto(decoder, target, target->br_merge());
}
void BrIf(FullDecoder* decoder, const Value& cond, uint32_t depth) {
SsaEnv* fenv = ssa_env_;
SsaEnv* tenv = Split(decoder, fenv);
fenv->SetNotMerged();
BUILD(BranchNoHint, cond.node, &tenv->control, &fenv->control);
SetEnv(tenv);
BrOrRet(decoder, depth);
SetEnv(fenv);
}
void BrTable(FullDecoder* decoder, const BranchTableImmediate<validate>& imm,
const Value& key) {
if (imm.table_count == 0) {
// Only a default target. Do the equivalent of br.
uint32_t target = BranchTableIterator<validate>(decoder, imm).next();
BrOrRet(decoder, target);
return;
}
SsaEnv* branch_env = ssa_env_;
// Build branches to the various blocks based on the table.
TFNode* sw = BUILD(Switch, imm.table_count + 1, key.node);
SsaEnv* copy = Steal(decoder->zone(), branch_env);
SetEnv(copy);
BranchTableIterator<validate> iterator(decoder, imm);
while (iterator.has_next()) {
uint32_t i = iterator.cur_index();
uint32_t target = iterator.next();
SetEnv(Split(decoder, copy));
ssa_env_->control =
(i == imm.table_count) ? BUILD(IfDefault, sw) : BUILD(IfValue, i, sw);
BrOrRet(decoder, target);
}
DCHECK(decoder->ok());
SetEnv(branch_env);
}
void Else(FullDecoder* decoder, Control* if_block) {
if (if_block->reachable()) {
// Merge the if branch into the end merge.
MergeValuesInto(decoder, if_block, &if_block->end_merge);
}
SetEnv(if_block->false_env);
}
void LoadMem(FullDecoder* decoder, LoadType type,
const MemoryAccessImmediate<validate>& imm, const Value& index,
Value* result) {
result->node =
BUILD(LoadMem, type.value_type(), type.mem_type(), index.node,
imm.offset, imm.alignment, decoder->position());
}
void StoreMem(FullDecoder* decoder, StoreType type,
const MemoryAccessImmediate<validate>& imm, const Value& index,
const Value& value) {
BUILD(StoreMem, type.mem_rep(), index.node, imm.offset, imm.alignment,
value.node, decoder->position(), type.value_type());
}
void CurrentMemoryPages(FullDecoder* decoder, Value* result) {
result->node = BUILD(CurrentMemoryPages);
}
void MemoryGrow(FullDecoder* decoder, const Value& value, Value* result) {
result->node = BUILD(MemoryGrow, value.node);
// Always reload the instance cache after growing memory.
LoadContextIntoSsa(ssa_env_);
}
void CallDirect(FullDecoder* decoder,
const CallFunctionImmediate<validate>& imm,
const Value args[], Value returns[]) {
DoCall(decoder, 0, nullptr, imm.sig, imm.index, args, returns);
}
void ReturnCall(FullDecoder* decoder,
const CallFunctionImmediate<validate>& imm,
const Value args[]) {
DoReturnCall(decoder, 0, nullptr, imm.sig, imm.index, args);
}
void CallIndirect(FullDecoder* decoder, const Value& index,
const CallIndirectImmediate<validate>& imm,
const Value args[], Value returns[]) {
DoCall(decoder, imm.table_index, index.node, imm.sig, imm.sig_index, args,
returns);
}
void ReturnCallIndirect(FullDecoder* decoder, const Value& index,
const CallIndirectImmediate<validate>& imm,
const Value args[]) {
DoReturnCall(decoder, imm.table_index, index.node, imm.sig, imm.sig_index,
args);
}
void SimdOp(FullDecoder* decoder, WasmOpcode opcode, Vector<Value> args,
Value* result) {
Vector<TFNode*> inputs = GetNodes(args);
TFNode* node = BUILD(SimdOp, opcode, inputs.begin());
if (result) result->node = node;
}
void SimdLaneOp(FullDecoder* decoder, WasmOpcode opcode,
const SimdLaneImmediate<validate> imm, Vector<Value> inputs,
Value* result) {
Vector<TFNode*> nodes = GetNodes(inputs);
result->node = BUILD(SimdLaneOp, opcode, imm.lane, nodes.begin());
}
void Simd8x16ShuffleOp(FullDecoder* decoder,
const Simd8x16ShuffleImmediate<validate>& imm,
const Value& input0, const Value& input1,
Value* result) {
TFNode* input_nodes[] = {input0.node, input1.node};
result->node = BUILD(Simd8x16ShuffleOp, imm.shuffle, input_nodes);
}
void Throw(FullDecoder* decoder, const ExceptionIndexImmediate<validate>& imm,
const Vector<Value>& value_args) {
int count = value_args.length();
ZoneVector<TFNode*> args(count, decoder->zone());
for (int i = 0; i < count; ++i) {
args[i] = value_args[i].node;
}
BUILD(Throw, imm.index, imm.exception, VectorOf(args), decoder->position());
builder_->TerminateThrow(ssa_env_->effect, ssa_env_->control);
}
void Rethrow(FullDecoder* decoder, const Value& exception) {
BUILD(Rethrow, exception.node);
builder_->TerminateThrow(ssa_env_->effect, ssa_env_->control);
}
void BrOnException(FullDecoder* decoder, const Value& exception,
const ExceptionIndexImmediate<validate>& imm,
uint32_t depth, Vector<Value> values) {
TFNode* if_match = nullptr;
TFNode* if_no_match = nullptr;
// Get the exception tag and see if it matches the expected one.
TFNode* caught_tag = BUILD(GetExceptionTag, exception.node);
TFNode* exception_tag = BUILD(LoadExceptionTagFromTable, imm.index);
TFNode* compare = BUILD(ExceptionTagEqual, caught_tag, exception_tag);
BUILD(BranchNoHint, compare, &if_match, &if_no_match);
SsaEnv* if_no_match_env = Split(decoder, ssa_env_);
SsaEnv* if_match_env = Steal(decoder->zone(), ssa_env_);
if_no_match_env->control = if_no_match;
if_match_env->control = if_match;
// If the tags match we extract the values from the exception object and
// push them onto the operand stack using the passed {values} vector.
SetEnv(if_match_env);
// TODO(mstarzinger): Can't use BUILD() here, GetExceptionValues() returns
// TFNode** rather than TFNode*. Fix to add landing pads.
Vector<TFNode*> caught_values =
builder_->GetExceptionValues(exception.node, imm.exception);
for (size_t i = 0, e = values.size(); i < e; ++i) {
values[i].node = caught_values[i];
}
BrOrRet(decoder, depth);
// If the tags don't match we fall-through here.
SetEnv(if_no_match_env);
}
void Catch(FullDecoder* decoder, Control* block, Value* exception) {
DCHECK(block->is_try_catch());
current_catch_ = block->previous_catch; // Pop try scope.
// The catch block is unreachable if no possible throws in the try block
// exist. We only build a landing pad if some node in the try block can
// (possibly) throw. Otherwise the catch environments remain empty.
if (!block->try_info->might_throw()) {
block->reachability = kSpecOnlyReachable;
return;
}
SetEnv(block->try_info->catch_env);
DCHECK_NOT_NULL(block->try_info->exception);
exception->node = block->try_info->exception;
}
void AtomicOp(FullDecoder* decoder, WasmOpcode opcode, Vector<Value> args,
const MemoryAccessImmediate<validate>& imm, Value* result) {
Vector<TFNode*> inputs = GetNodes(args);
TFNode* node = BUILD(AtomicOp, opcode, inputs.begin(), imm.alignment,
imm.offset, decoder->position());
if (result) result->node = node;
}
void AtomicFence(FullDecoder* decoder) { BUILD(AtomicFence); }
void MemoryInit(FullDecoder* decoder,
const MemoryInitImmediate<validate>& imm, const Value& dst,
const Value& src, const Value& size) {
BUILD(MemoryInit, imm.data_segment_index, dst.node, src.node, size.node,
decoder->position());
}
void DataDrop(FullDecoder* decoder, const DataDropImmediate<validate>& imm) {
BUILD(DataDrop, imm.index, decoder->position());
}
void MemoryCopy(FullDecoder* decoder,
const MemoryCopyImmediate<validate>& imm, const Value& dst,
const Value& src, const Value& size) {
BUILD(MemoryCopy, dst.node, src.node, size.node, decoder->position());
}
void MemoryFill(FullDecoder* decoder,
const MemoryIndexImmediate<validate>& imm, const Value& dst,
const Value& value, const Value& size) {
BUILD(MemoryFill, dst.node, value.node, size.node, decoder->position());
}
void TableInit(FullDecoder* decoder, const TableInitImmediate<validate>& imm,
Vector<Value> args) {
BUILD(TableInit, imm.table.index, imm.elem_segment_index, args[0].node,
args[1].node, args[2].node, decoder->position());
}
void ElemDrop(FullDecoder* decoder, const ElemDropImmediate<validate>& imm) {
BUILD(ElemDrop, imm.index, decoder->position());
}
void TableCopy(FullDecoder* decoder, const TableCopyImmediate<validate>& imm,
Vector<Value> args) {
BUILD(TableCopy, imm.table_dst.index, imm.table_src.index, args[0].node,
args[1].node, args[2].node, decoder->position());
}
void TableGrow(FullDecoder* decoder, const TableIndexImmediate<validate>& imm,
Value& value, Value& delta, Value* result) {
result->node = BUILD(TableGrow, imm.index, value.node, delta.node);
}
void TableSize(FullDecoder* decoder, const TableIndexImmediate<validate>& imm,
Value* result) {
result->node = BUILD(TableSize, imm.index);
}
void TableFill(FullDecoder* decoder, const TableIndexImmediate<validate>& imm,
Value& start, Value& value, Value& count) {
BUILD(TableFill, imm.index, start.node, value.node, count.node);
}
private:
SsaEnv* ssa_env_;
compiler::WasmGraphBuilder* builder_;
uint32_t current_catch_ = kNullCatch;
TryInfo* current_try_info(FullDecoder* decoder) {
return decoder->control_at(decoder->control_depth() - 1 - current_catch_)
->try_info;
}
Vector<TFNode*> GetNodes(Value* values, size_t count) {
Vector<TFNode*> nodes = builder_->Buffer(count);
for (size_t i = 0; i < count; ++i) {
nodes[i] = values[i].node;
}
return nodes;
}
Vector<TFNode*> GetNodes(Vector<Value> values) {
return GetNodes(values.begin(), values.size());
}
void SetEnv(SsaEnv* env) {
#if DEBUG
if (FLAG_trace_wasm_decoder) {
char state = 'X';
if (env) {
switch (env->state) {
case SsaEnv::kReached:
state = 'R';
break;
case SsaEnv::kUnreachable:
state = 'U';
break;
case SsaEnv::kMerged:
state = 'M';
break;
case SsaEnv::kControlEnd:
state = 'E';
break;
}
}
PrintF("{set_env = %p, state = %c", env, state);
if (env && env->control) {
PrintF(", control = ");
compiler::WasmGraphBuilder::PrintDebugName(env->control);
}
PrintF("}\n");
}
#endif
ssa_env_ = env;
// TODO(wasm): combine the control and effect pointers with instance cache.
builder_->set_control_ptr(&env->control);
builder_->set_effect_ptr(&env->effect);
builder_->set_instance_cache(&env->instance_cache);
}
TFNode* CheckForException(FullDecoder* decoder, TFNode* node) {
if (node == nullptr) return nullptr;
const bool inside_try_scope = current_catch_ != kNullCatch;
if (!inside_try_scope) return node;
TFNode* if_success = nullptr;
TFNode* if_exception = nullptr;
if (!builder_->ThrowsException(node, &if_success, &if_exception)) {
return node;
}
SsaEnv* success_env = Steal(decoder->zone(), ssa_env_);
success_env->control = if_success;
SsaEnv* exception_env = Split(decoder, success_env);
exception_env->control = if_exception;
TryInfo* try_info = current_try_info(decoder);
Goto(decoder, exception_env, try_info->catch_env);
TFNode* exception = try_info->exception;
if (exception == nullptr) {
DCHECK_EQ(SsaEnv::kReached, try_info->catch_env->state);
try_info->exception = if_exception;
} else {
DCHECK_EQ(SsaEnv::kMerged, try_info->catch_env->state);
try_info->exception = builder_->CreateOrMergeIntoPhi(
MachineRepresentation::kWord32, try_info->catch_env->control,
try_info->exception, if_exception);
}
SetEnv(success_env);
return node;
}
TFNode* DefaultValue(ValueType type) {
switch (type) {
case kWasmI32:
return builder_->Int32Constant(0);
case kWasmI64:
return builder_->Int64Constant(0);
case kWasmF32:
return builder_->Float32Constant(0);
case kWasmF64:
return builder_->Float64Constant(0);
case kWasmS128:
return builder_->S128Zero();
case kWasmAnyRef:
case kWasmFuncRef:
case kWasmExnRef:
return builder_->RefNull();
default:
UNREACHABLE();
}
}
void MergeValuesInto(FullDecoder* decoder, Control* c, Merge<Value>* merge) {
DCHECK(merge == &c->start_merge || merge == &c->end_merge);
SsaEnv* target = c->end_env;
const bool first = target->state == SsaEnv::kUnreachable;
Goto(decoder, ssa_env_, target);
if (merge->arity == 0) return;
uint32_t avail =
decoder->stack_size() - decoder->control_at(0)->stack_depth;
DCHECK_GE(avail, merge->arity);
uint32_t start = avail >= merge->arity ? 0 : merge->arity - avail;
Value* stack_values = decoder->stack_value(merge->arity);
for (uint32_t i = start; i < merge->arity; ++i) {
Value& val = stack_values[i];
Value& old = (*merge)[i];
DCHECK_NOT_NULL(val.node);
DCHECK(val.type == kWasmBottom ||
ValueTypes::MachineRepresentationFor(val.type) ==
ValueTypes::MachineRepresentationFor(old.type));
old.node = first ? val.node
: builder_->CreateOrMergeIntoPhi(
ValueTypes::MachineRepresentationFor(old.type),
target->control, old.node, val.node);
}
}
void Goto(FullDecoder* decoder, SsaEnv* from, SsaEnv* to) {
DCHECK_NOT_NULL(to);
switch (to->state) {
case SsaEnv::kUnreachable: { // Overwrite destination.
to->state = SsaEnv::kReached;
to->locals = from->locals;
to->control = from->control;
to->effect = from->effect;
to->instance_cache = from->instance_cache;
break;
}
case SsaEnv::kReached: { // Create a new merge.
to->state = SsaEnv::kMerged;
// 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 = decoder->num_locals() - 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(decoder->GetLocalType(i), 2, vals, merge);
}
}
// Start a new merge from the instance cache.
builder_->NewInstanceCacheMerge(&to->instance_cache,
&from->instance_cache, merge);
break;
}
case SsaEnv::kMerged: {
TFNode* merge = to->control;
// Extend the existing merge control node.
builder_->AppendToMerge(merge, from->control);
// Merge effects.
to->effect = builder_->CreateOrMergeIntoEffectPhi(merge, to->effect,
from->effect);
// Merge locals.
for (int i = decoder->num_locals() - 1; i >= 0; i--) {
to->locals[i] = builder_->CreateOrMergeIntoPhi(
ValueTypes::MachineRepresentationFor(decoder->GetLocalType(i)),
merge, to->locals[i], from->locals[i]);
}
// Merge the instance caches.
builder_->MergeInstanceCacheInto(&to->instance_cache,
&from->instance_cache, merge);
break;
}
default:
UNREACHABLE();
}
return from->Kill();
}
SsaEnv* PrepareForLoop(FullDecoder* decoder, SsaEnv* env) {
env->state = SsaEnv::kMerged;
env->control = builder_->Loop(env->control);
env->effect = builder_->EffectPhi(1, &env->effect, env->control);
builder_->TerminateLoop(env->effect, env->control);
// The '+ 1' here is to be able to set the instance cache as assigned.
BitVector* assigned = WasmDecoder<validate>::AnalyzeLoopAssignment(
decoder, decoder->pc(), decoder->total_locals() + 1, decoder->zone());
if (decoder->failed()) return env;
if (assigned != nullptr) {
// Only introduce phis for variables assigned in this loop.
int instance_cache_index = decoder->total_locals();
for (int i = decoder->num_locals() - 1; i >= 0; i--) {
if (!assigned->Contains(i)) continue;
env->locals[i] = builder_->Phi(decoder->GetLocalType(i), 1,
&env->locals[i], env->control);
}
// Introduce phis for instance cache pointers if necessary.
if (assigned->Contains(instance_cache_index)) {
builder_->PrepareInstanceCacheForLoop(&env->instance_cache,
env->control);
}
SsaEnv* loop_body_env = Split(decoder, env);
builder_->StackCheck(decoder->position(), &(loop_body_env->effect),
&(loop_body_env->control));
return loop_body_env;
}
// Conservatively introduce phis for all local variables.
for (int i = decoder->num_locals() - 1; i >= 0; i--) {
env->locals[i] = builder_->Phi(decoder->GetLocalType(i), 1,
&env->locals[i], env->control);
}
// Conservatively introduce phis for instance cache.
builder_->PrepareInstanceCacheForLoop(&env->instance_cache, env->control);
SsaEnv* loop_body_env = Split(decoder, env);
builder_->StackCheck(decoder->position(), &loop_body_env->effect,
&loop_body_env->control);
return loop_body_env;
}
// Create a complete copy of {from}.
SsaEnv* Split(FullDecoder* decoder, SsaEnv* from) {
DCHECK_NOT_NULL(from);
SsaEnv* result =
reinterpret_cast<SsaEnv*>(decoder->zone()->New(sizeof(SsaEnv)));
size_t size = sizeof(TFNode*) * decoder->num_locals();
result->control = from->control;
result->effect = from->effect;
result->state = SsaEnv::kReached;
if (size > 0) {
result->locals = reinterpret_cast<TFNode**>(decoder->zone()->New(size));
memcpy(result->locals, from->locals, size);
} else {
result->locals = nullptr;
}
result->instance_cache = from->instance_cache;
return result;
}
// Create a copy of {from} that steals its state and leaves {from}
// unreachable.
SsaEnv* Steal(Zone* zone, SsaEnv* from) {
DCHECK_NOT_NULL(from);
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;
result->instance_cache = from->instance_cache;
from->Kill(SsaEnv::kUnreachable);
return result;
}
// Create an unreachable environment.
SsaEnv* UnreachableEnv(Zone* zone) {
SsaEnv* result = reinterpret_cast<SsaEnv*>(zone->New(sizeof(SsaEnv)));
result->state = SsaEnv::kUnreachable;
result->control = nullptr;
result->effect = nullptr;
result->locals = nullptr;
result->instance_cache = {};
return result;
}
void DoCall(FullDecoder* decoder, uint32_t table_index, TFNode* index_node,
FunctionSig* sig, uint32_t sig_index, const Value args[],
Value returns[]) {
int param_count = static_cast<int>(sig->parameter_count());
Vector<TFNode*> arg_nodes = builder_->Buffer(param_count + 1);
TFNode** return_nodes = nullptr;
arg_nodes[0] = index_node;
for (int i = 0; i < param_count; ++i) {
arg_nodes[i + 1] = args[i].node;
}
if (index_node) {
BUILD(CallIndirect, table_index, sig_index, arg_nodes.begin(),
&return_nodes, decoder->position());
} else {
BUILD(CallDirect, sig_index, arg_nodes.begin(), &return_nodes,
decoder->position());
}
int return_count = static_cast<int>(sig->return_count());
for (int i = 0; i < return_count; ++i) {
returns[i].node = return_nodes[i];
}
// The invoked function could have used grow_memory, so we need to
// reload mem_size and mem_start.
LoadContextIntoSsa(ssa_env_);
}
void DoReturnCall(FullDecoder* decoder, uint32_t table_index,
TFNode* index_node, FunctionSig* sig, uint32_t sig_index,
const Value args[]) {
int arg_count = static_cast<int>(sig->parameter_count());
Vector<TFNode*> arg_nodes = builder_->Buffer(arg_count + 1);
arg_nodes[0] = index_node;
for (int i = 0; i < arg_count; ++i) {
arg_nodes[i + 1] = args[i].node;
}
if (index_node) {
BUILD(ReturnCallIndirect, table_index, sig_index, arg_nodes.begin(),
decoder->position());
} else {
BUILD(ReturnCall, sig_index, arg_nodes.begin(), decoder->position());
}
}
};
} // namespace
DecodeResult BuildTFGraph(AccountingAllocator* allocator,
const WasmFeatures& enabled, const WasmModule* module,
compiler::WasmGraphBuilder* builder,
WasmFeatures* detected, const FunctionBody& body,
compiler::NodeOriginTable* node_origins) {
Zone zone(allocator, ZONE_NAME);
WasmFullDecoder<Decoder::kValidate, WasmGraphBuildingInterface> decoder(
&zone, module, enabled, detected, body, builder);
if (node_origins) {
builder->AddBytecodePositionDecorator(node_origins, &decoder);
}
decoder.Decode();
if (node_origins) {
builder->RemoveBytecodePositionDecorator();
}
return decoder.toResult(nullptr);
}
#undef BUILD
} // namespace wasm
} // namespace internal
} // namespace v8