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[wasm][refactor] Improve SsaEnv implementation

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- Add a default, move, and copy constructor for SsaEnv and use them
  when possible.
- Bring the Split method signature in line with Steal and
  Unimplemented.

Changes: 
Change-Id: I626142fbd1c1ed15c1852b9bfc8b39a0e936b839
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2204278
Commit-Queue: Manos Koukoutos <manoskouk@chromium.org>
Reviewed-by: Clemens Backes <clemensb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#67871}
This commit is contained in:
Manos Koukoutos 2020-05-18 14:43:02 +00:00 committed by Commit Bot
parent b50d91960c
commit 4f3b9ddd8c
1 changed files with 32 additions and 37 deletions
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69
src/wasm/graph-builder-interface.cc
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@ -37,7 +37,21 @@ struct SsaEnv : public ZoneObject {
compiler::WasmInstanceCacheNodes instance_cache;
ZoneVector<TFNode*> locals;
explicit SsaEnv(Zone* zone) : locals(zone) {}
SsaEnv(Zone* zone, State state, TFNode* control, TFNode* effect,
uint32_t locals_size)
: state(state), control(control), effect(effect), locals(zone) {
if (locals_size > 0) locals.resize(locals_size);
}
SsaEnv(const SsaEnv& other) V8_NOEXCEPT = default;
SsaEnv(SsaEnv&& other) V8_NOEXCEPT : state(other.state),
control(other.control),
effect(other.effect),
instance_cache(other.instance_cache),
locals(std::move(other.locals)) {
other.Kill(kUnreachable);
}
void Kill(State new_state = kControlEnd) {
state = new_state;
locals.clear();
@ -99,17 +113,14 @@ class WasmGraphBuildingInterface {
: builder_(builder) {}
void StartFunction(FullDecoder* decoder) {
SsaEnv* ssa_env = new (decoder->zone()) SsaEnv(decoder->zone());
uint32_t num_locals = decoder->num_locals();
ssa_env->state = SsaEnv::kReached;
ssa_env->locals.resize(num_locals);
// 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;
uint32_t num_locals = decoder->num_locals();
SsaEnv* ssa_env = new (decoder->zone())
SsaEnv(decoder->zone(), SsaEnv::kReached, start, start, num_locals);
// Initialize effect and control before initializing the locals default
// values (which might require instance loads) or loading the context.
builder_->SetEffectControl(start);
@ -170,7 +181,7 @@ class WasmGraphBuildingInterface {
void Try(FullDecoder* decoder, Control* block) {
SsaEnv* outer_env = ssa_env_;
SsaEnv* catch_env = Split(decoder, outer_env);
SsaEnv* catch_env = Split(decoder->zone(), outer_env);
// Mark catch environment as unreachable, since only accessable
// through catch unwinding (i.e. landing pads).
catch_env->state = SsaEnv::kUnreachable;
@ -188,7 +199,7 @@ class WasmGraphBuildingInterface {
TFNode* if_false = nullptr;
BUILD(BranchNoHint, cond.node, &if_true, &if_false);
SsaEnv* end_env = ssa_env_;
SsaEnv* false_env = Split(decoder, ssa_env_);
SsaEnv* false_env = Split(decoder->zone(), ssa_env_);
false_env->control = if_false;
SsaEnv* true_env = Steal(decoder->zone(), ssa_env_);
true_env->control = if_true;
@ -339,7 +350,7 @@ class WasmGraphBuildingInterface {
void BrIf(FullDecoder* decoder, const Value& cond, uint32_t depth) {
SsaEnv* fenv = ssa_env_;
SsaEnv* tenv = Split(decoder, fenv);
SsaEnv* tenv = Split(decoder->zone(), fenv);
fenv->SetNotMerged();
BUILD(BranchNoHint, cond.node, &tenv->control, &fenv->control);
builder_->SetControl(fenv->control);
@ -367,7 +378,7 @@ class WasmGraphBuildingInterface {
while (iterator.has_next()) {
uint32_t i = iterator.cur_index();
uint32_t target = iterator.next();
SetEnv(Split(decoder, copy));
SetEnv(Split(decoder->zone(), copy));
builder_->SetControl(i == imm.table_count ? BUILD(IfDefault, sw)
: BUILD(IfValue, i, sw));
BrOrRet(decoder, target);
@ -446,7 +457,7 @@ class WasmGraphBuildingInterface {
void BrOnNull(FullDecoder* decoder, const Value& ref_object, uint32_t depth) {
SsaEnv* non_null_env = ssa_env_;
SsaEnv* null_env = Split(decoder, non_null_env);
SsaEnv* null_env = Split(decoder->zone(), non_null_env);
non_null_env->SetNotMerged();
BUILD(BrOnNull, ref_object.node, &null_env->control,
&non_null_env->control);
@ -508,7 +519,7 @@ class WasmGraphBuildingInterface {
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_no_match_env = Split(decoder->zone(), 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;
@ -749,7 +760,7 @@ class WasmGraphBuildingInterface {
SsaEnv* success_env = Steal(decoder->zone(), ssa_env_);
success_env->control = if_success;
SsaEnv* exception_env = Split(decoder, success_env);
SsaEnv* exception_env = Split(decoder->zone(), success_env);
exception_env->control = if_exception;
exception_env->effect = if_exception;
SetEnv(exception_env);
@ -916,7 +927,7 @@ class WasmGraphBuildingInterface {
control());
}
SetEnv(Split(decoder, ssa_env_));
SetEnv(Split(decoder->zone(), ssa_env_));
builder_->StackCheck(decoder->position());
return;
}
@ -930,25 +941,19 @@ class WasmGraphBuildingInterface {
// Conservatively introduce phis for instance cache.
builder_->PrepareInstanceCacheForLoop(&ssa_env_->instance_cache, control());
SetEnv(Split(decoder, ssa_env_));
SetEnv(Split(decoder->zone(), ssa_env_));
builder_->StackCheck(decoder->position());
}
// Create a complete copy of {from}.
SsaEnv* Split(FullDecoder* decoder, SsaEnv* from) {
SsaEnv* Split(Zone* zone, SsaEnv* from) {
DCHECK_NOT_NULL(from);
if (from == ssa_env_) {
ssa_env_->control = control();
ssa_env_->effect = effect();
}
SsaEnv* result = new (decoder->zone()) SsaEnv(decoder->zone());
result->control = from->control;
result->effect = from->effect;
SsaEnv* result = new (zone) SsaEnv(*from);
result->state = SsaEnv::kReached;
result->locals = from->locals;
result->instance_cache = from->instance_cache;
return result;
}
@ -960,24 +965,14 @@ class WasmGraphBuildingInterface {
ssa_env_->control = control();
ssa_env_->effect = effect();
}
SsaEnv* result = new (zone) SsaEnv(zone);
SsaEnv* result = new (zone) SsaEnv(std::move(*from));
result->state = SsaEnv::kReached;
result->locals = std::move(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 = new (zone) SsaEnv(zone);
result->state = SsaEnv::kUnreachable;
result->control = nullptr;
result->effect = nullptr;
result->instance_cache = {};
return result;
return new (zone) SsaEnv(zone, SsaEnv::kUnreachable, nullptr, nullptr, 0);
}
void DoCall(FullDecoder* decoder, uint32_t table_index, TFNode* index_node,