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[wasm] Refactor storage of argument vector

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The function body decoder stored popped arguments in a field of the
decoder class, which is a non-obvious side channel.
This CL refactors this to return the popped vector directly instead.
In local benchmarks, this has no measurable performance impact.

R=titzer@chromium.org

Bug: v8:9183
Change-Id: I79b28e349e3009b9f01be25f116c4085ca569ca7
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1596732
Reviewed-by: Ben Titzer <titzer@chromium.org>
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#61379}
This commit is contained in:
Clemens Hammacher 2019-05-06 15:00:51 +02:00 committed by Commit Bot
parent 652e32f9f9
commit f11129f342
1 changed files with 36 additions and 37 deletions
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73
src/wasm/function-body-decoder-impl.h
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@ -9,6 +9,7 @@
// WasmFullDecoder.
#include "src/base/platform/elapsed-timer.h"
#include "src/base/small-vector.h"
#include "src/bit-vector.h"
#include "src/wasm/decoder.h"
#include "src/wasm/function-body-decoder.h"
@ -1482,6 +1483,7 @@ class WasmFullDecoder : public WasmDecoder<validate> {
using Value = typename Interface::Value;
using Control = typename Interface::Control;
using MergeValues = Merge<Value>;
using ArgVector = base::SmallVector<Value, 8>;
// All Value types should be trivially copyable for performance. We push, pop,
// and store them in local variables.
@ -1498,8 +1500,7 @@ class WasmFullDecoder : public WasmDecoder<validate> {
interface_(std::forward<InterfaceArgs>(interface_args)...),
local_type_vec_(zone),
stack_(zone),
control_(zone),
args_(zone) {
control_(zone) {
this->local_types_ = &local_type_vec_;
}
@ -1612,7 +1613,6 @@ class WasmFullDecoder : public WasmDecoder<validate> {
ZoneVector<ValueType> local_type_vec_; // types of local variables.
ZoneVector<Value> stack_; // stack of values.
ZoneVector<Control> control_; // stack of blocks, loops, and ifs.
ZoneVector<Value> args_; // parameters of current block or call
static Value UnreachableValue(const uint8_t* pc) {
return Value{pc, kWasmVar};
@ -1708,9 +1708,9 @@ class WasmFullDecoder : public WasmDecoder<validate> {
case kExprBlock: {
BlockTypeImmediate<validate> imm(this->enabled_, this, this->pc_);
if (!this->Validate(imm)) break;
PopArgs(imm.sig);
auto args = PopArgs(imm.sig);
auto* block = PushControl(kControlBlock);
SetBlockType(block, imm);
SetBlockType(block, imm, args.begin());
CALL_INTERFACE_IF_REACHABLE(Block, block);
PushMergeValues(block, &block->start_merge);
len = 1 + imm.length;
@ -1728,8 +1728,8 @@ class WasmFullDecoder : public WasmDecoder<validate> {
ExceptionIndexImmediate<validate> imm(this, this->pc_);
len = 1 + imm.length;
if (!this->Validate(this->pc_, imm)) break;
PopArgs(imm.exception->ToFunctionSig());
CALL_INTERFACE_IF_REACHABLE(Throw, imm, VectorOf(args_));
auto args = PopArgs(imm.exception->ToFunctionSig());
CALL_INTERFACE_IF_REACHABLE(Throw, imm, VectorOf(args));
EndControl();
break;
}
@ -1737,9 +1737,9 @@ class WasmFullDecoder : public WasmDecoder<validate> {
CHECK_PROTOTYPE_OPCODE(eh);
BlockTypeImmediate<validate> imm(this->enabled_, this, this->pc_);
if (!this->Validate(imm)) break;
PopArgs(imm.sig);
auto args = PopArgs(imm.sig);
auto* try_block = PushControl(kControlTry);
SetBlockType(try_block, imm);
SetBlockType(try_block, imm, args.begin());
len = 1 + imm.length;
CALL_INTERFACE_IF_REACHABLE(Try, try_block);
PushMergeValues(try_block, &try_block->start_merge);
@ -1798,9 +1798,9 @@ class WasmFullDecoder : public WasmDecoder<validate> {
case kExprLoop: {
BlockTypeImmediate<validate> imm(this->enabled_, this, this->pc_);
if (!this->Validate(imm)) break;
PopArgs(imm.sig);
auto args = PopArgs(imm.sig);
auto* block = PushControl(kControlLoop);
SetBlockType(&control_.back(), imm);
SetBlockType(&control_.back(), imm, args.begin());
len = 1 + imm.length;
CALL_INTERFACE_IF_REACHABLE(Loop, block);
PushMergeValues(block, &block->start_merge);
@ -1810,10 +1810,10 @@ class WasmFullDecoder : public WasmDecoder<validate> {
BlockTypeImmediate<validate> imm(this->enabled_, this, this->pc_);
if (!this->Validate(imm)) break;
auto cond = Pop(0, kWasmI32);
PopArgs(imm.sig);
auto args = PopArgs(imm.sig);
if (!VALIDATE(this->ok())) break;
auto* if_block = PushControl(kControlIf);
SetBlockType(if_block, imm);
SetBlockType(if_block, imm, args.begin());
CALL_INTERFACE_IF_REACHABLE(If, cond, if_block);
len = 1 + imm.length;
PushMergeValues(if_block, &if_block->start_merge);
@ -2179,10 +2179,9 @@ class WasmFullDecoder : public WasmDecoder<validate> {
CallFunctionImmediate<validate> imm(this, this->pc_);
len = 1 + imm.length;
if (!this->Validate(this->pc_, imm)) break;
// TODO(clemensh): Better memory management.
PopArgs(imm.sig);
auto args = PopArgs(imm.sig);
auto* returns = PushReturns(imm.sig);
CALL_INTERFACE_IF_REACHABLE(CallDirect, imm, args_.data(), returns);
CALL_INTERFACE_IF_REACHABLE(CallDirect, imm, args.begin(), returns);
break;
}
case kExprCallIndirect: {
@ -2190,9 +2189,9 @@ class WasmFullDecoder : public WasmDecoder<validate> {
len = 1 + imm.length;
if (!this->Validate(this->pc_, imm)) break;
auto index = Pop(0, kWasmI32);
PopArgs(imm.sig);
auto args = PopArgs(imm.sig);
auto* returns = PushReturns(imm.sig);
CALL_INTERFACE_IF_REACHABLE(CallIndirect, index, imm, args_.data(),
CALL_INTERFACE_IF_REACHABLE(CallIndirect, index, imm, args.begin(),
returns);
break;
}
@ -2207,9 +2206,9 @@ class WasmFullDecoder : public WasmDecoder<validate> {
break;
}
PopArgs(imm.sig);
auto args = PopArgs(imm.sig);
CALL_INTERFACE_IF_REACHABLE(ReturnCall, imm, args_.data());
CALL_INTERFACE_IF_REACHABLE(ReturnCall, imm, args.begin());
EndControl();
break;
}
@ -2223,9 +2222,9 @@ class WasmFullDecoder : public WasmDecoder<validate> {
break;
}
auto index = Pop(0, kWasmI32);
PopArgs(imm.sig);
auto args = PopArgs(imm.sig);
CALL_INTERFACE_IF_REACHABLE(ReturnCallIndirect, index, imm,
args_.data());
args.begin());
EndControl();
break;
}
@ -2383,10 +2382,9 @@ class WasmFullDecoder : public WasmDecoder<validate> {
}
}
void SetBlockType(Control* c, BlockTypeImmediate<validate>& imm) {
DCHECK_EQ(imm.in_arity(), this->args_.size());
void SetBlockType(Control* c, BlockTypeImmediate<validate>& imm,
Value* args) {
const byte* pc = this->pc_;
Value* args = this->args_.data();
InitMerge(&c->end_merge, imm.out_arity(), [pc, &imm](uint32_t i) {
return Value{pc, imm.out_type(i)};
});
@ -2394,13 +2392,14 @@ class WasmFullDecoder : public WasmDecoder<validate> {
[args](uint32_t i) { return args[i]; });
}
// Pops arguments as required by signature into {args_}.
V8_INLINE void PopArgs(FunctionSig* sig) {
// Pops arguments as required by signature.
V8_INLINE ArgVector PopArgs(FunctionSig* sig) {
int count = sig ? static_cast<int>(sig->parameter_count()) : 0;
args_.resize(count, UnreachableValue(nullptr));
ArgVector args(count);
for (int i = count - 1; i >= 0; --i) {
args_[i] = Pop(i, sig->GetParam(i));
args[i] = Pop(i, sig->GetParam(i));
}
return args;
}
ValueType GetReturnType(FunctionSig* sig) {
@ -2550,10 +2549,10 @@ class WasmFullDecoder : public WasmDecoder<validate> {
this->error("invalid simd opcode");
break;
}
PopArgs(sig);
auto args = PopArgs(sig);
auto* results =
sig->return_count() == 0 ? nullptr : Push(GetReturnType(sig));
CALL_INTERFACE_IF_REACHABLE(SimdOp, opcode, VectorOf(args_), results);
CALL_INTERFACE_IF_REACHABLE(SimdOp, opcode, VectorOf(args), results);
}
}
return len;
@ -2589,9 +2588,9 @@ class WasmFullDecoder : public WasmDecoder<validate> {
MemoryAccessImmediate<validate> imm(
this, this->pc_ + 1, ElementSizeLog2Of(memtype.representation()));
len += imm.length;
PopArgs(sig);
auto args = PopArgs(sig);
auto result = ret_type == kWasmStmt ? nullptr : Push(GetReturnType(sig));
CALL_INTERFACE_IF_REACHABLE(AtomicOp, opcode, VectorOf(args_), imm,
CALL_INTERFACE_IF_REACHABLE(AtomicOp, opcode, VectorOf(args), imm,
result);
} else {
this->error("invalid atomic opcode");
@ -2655,8 +2654,8 @@ class WasmFullDecoder : public WasmDecoder<validate> {
TableInitImmediate<validate> imm(this, this->pc_);
if (!this->Validate(imm)) break;
len += imm.length;
PopArgs(sig);
CALL_INTERFACE_IF_REACHABLE(TableInit, imm, VectorOf(args_));
auto args = PopArgs(sig);
CALL_INTERFACE_IF_REACHABLE(TableInit, imm, VectorOf(args));
break;
}
case kExprElemDrop: {
@ -2670,8 +2669,8 @@ class WasmFullDecoder : public WasmDecoder<validate> {
TableCopyImmediate<validate> imm(this, this->pc_);
if (!this->Validate(imm)) break;
len += imm.length;
PopArgs(sig);
CALL_INTERFACE_IF_REACHABLE(TableCopy, imm, VectorOf(args_));
auto args = PopArgs(sig);
CALL_INTERFACE_IF_REACHABLE(TableCopy, imm, VectorOf(args));
break;
}
case kExprTableGrow: {