Reviewers: Toon Verwaest,
Description:
Fix phis for non-sse2 double values
Since hydrogen will try to merge phi-inputs using registers, even if
the values are spilled, we cannot mark LGoto as double clobbering
instruction.
BUG=
Please review this at https://codereview.chromium.org/23068038/
SVN Base: https://v8.googlecode.com/svn/branches/bleeding_edge
Affected files:
M src/ia32/lithium-codegen-ia32.h
M src/ia32/lithium-codegen-ia32.cc
M src/ia32/lithium-ia32.h
src/ia32/lithium-ia32.cc
Index: src/ia32/lithium-codegen-ia32.cc
diff --git a/src/ia32/lithium-codegen-ia32.cc
b/src/ia32/lithium-codegen-ia32.cc
index
75525ed5be95ee7723968a0084687de7c440c3c7..e6e763e6550f5913e59a9fd2d25bc64173252c55
100644
--- a/src/ia32/lithium-codegen-ia32.cc
+++ b/src/ia32/lithium-codegen-ia32.cc
@@ -359,9 +359,13 @@ bool LCodeGen::GenerateBody() {
instr->CompileToNative(this);
- if (!CpuFeatures::IsSupported(SSE2) &&
- FLAG_debug_code && FLAG_enable_slow_asserts) {
+ if (!CpuFeatures::IsSupported(SSE2)) {
+ if (instr->IsGoto()) {
+ x87_stack_.LeavingBlock(current_block_, LGoto::cast(instr));
+ } else if (FLAG_debug_code && FLAG_enable_slow_asserts &&
+ !instr->IsGap() && !instr->IsReturn()) {
__ VerifyX87StackDepth(x87_stack_.depth());
+ }
}
}
EnsureSpaceForLazyDeopt();
@@ -659,6 +663,18 @@ void
LCodeGen::X87Stack::FlushIfNecessary(LInstruction* instr, LCodeGen* cgen) {
__ fstp(0);
stack_depth_--;
}
+ __ VerifyX87StackDepth(0);
+ }
+}
+
+
+void LCodeGen::X87Stack::LeavingBlock(int current_block_id, LGoto*
goto_instr) {
+ ASSERT(stack_depth_ <= 1);
+ if (current_block_id + 1 != goto_instr->block_id()) {
+ // If we have a value on the x87 stack on leaving a block, it must be a
+ // phi input. If the next block we compile is not the join block, we
have
+ // to discard the stack state.
+ stack_depth_ = 0;
}
}
@@ -2439,6 +2455,10 @@ void LCodeGen::EmitGoto(int block) {
}
+void LCodeGen::DoClobberDoubles(LClobberDoubles* instr) {
+}
+
+
void LCodeGen::DoGoto(LGoto* instr) {
EmitGoto(instr->block_id());
}
Index: src/ia32/lithium-codegen-ia32.h
diff --git a/src/ia32/lithium-codegen-ia32.h
b/src/ia32/lithium-codegen-ia32.h
index
23b2e48fb0c5c403ecec0cb60a6143d1151212fa..a7a1a4755fc5b8fdb01540784a62fb0560bc3db6
100644
--- a/src/ia32/lithium-codegen-ia32.h
+++ b/src/ia32/lithium-codegen-ia32.h
@@ -468,6 +468,7 @@ class LCodeGen V8_FINAL BASE_EMBEDDED {
void PrepareToWrite(X87Register reg);
void CommitWrite(X87Register reg);
void FlushIfNecessary(LInstruction* instr, LCodeGen* cgen);
+ void LeavingBlock(int current_block_id, LGoto* goto_instr);
int depth() const { return stack_depth_; }
void pop() {
ASSERT(is_mutable_);
Index: src/ia32/lithium-ia32.cc
diff --git a/src/ia32/lithium-ia32.cc b/src/ia32/lithium-ia32.cc
index
8d660858508411408bd1ffc9aa31f7a86a22873b..aa686bfe8307a8627beaef9492fb288b71d7369c
100644
--- a/src/ia32/lithium-ia32.cc
+++ b/src/ia32/lithium-ia32.cc
@@ -945,6 +945,16 @@ void LChunkBuilder::VisitInstruction(HInstruction*
current) {
if (FLAG_stress_environments && !instr->HasEnvironment()) {
instr = AssignEnvironment(instr);
}
+ if (!CpuFeatures::IsSafeForSnapshot(SSE2) && instr->IsGoto() &&
+ LGoto::cast(instr)->jumps_to_join()) {
+ // TODO(olivf) Since phis of spilled values are joined as registers
+ // (not in the stack slot), we need to allow the goto gaps to keep
one
+ // x87 register alive. To ensure all other values are still spilled,
we
+ // insert a fpu register barrier right before.
+ LClobberDoubles* clobber = new(zone()) LClobberDoubles();
+ clobber->set_hydrogen_value(current);
+ chunk_->AddInstruction(clobber, current_block_);
+ }
instr->set_hydrogen_value(current);
chunk_->AddInstruction(instr, current_block_);
}
@@ -1037,7 +1047,7 @@ LEnvironment* LChunkBuilder::CreateEnvironment(
LInstruction* LChunkBuilder::DoGoto(HGoto* instr) {
- return new(zone()) LGoto(instr->FirstSuccessor()->block_id());
+ return new(zone()) LGoto(instr->FirstSuccessor());
}
@@ -1049,7 +1059,7 @@ LInstruction* LChunkBuilder::DoBranch(HBranch* instr)
{
HBasicBlock* successor = HConstant::cast(value)->BooleanValue()
? instr->FirstSuccessor()
: instr->SecondSuccessor();
- return new(zone()) LGoto(successor->block_id());
+ return new(zone()) LGoto(successor);
}
ToBooleanStub::Types expected = instr->expected_input_types();
Index: src/ia32/lithium-ia32.h
diff --git a/src/ia32/lithium-ia32.h b/src/ia32/lithium-ia32.h
index
8b311b7ae9c857e392ef51e5445a8a026b78b0c3..9e072f26c4bd1a3d50ff5af2d00b1b73da367a51
100644
--- a/src/ia32/lithium-ia32.h
+++ b/src/ia32/lithium-ia32.h
@@ -73,6 +73,7 @@ class LCodeGen;
V(ClampTToUint8) \
V(ClampTToUint8NoSSE2) \
V(ClassOfTestAndBranch) \
+ V(ClobberDoubles) \
V(CompareNumericAndBranch) \
V(CmpObjectEqAndBranch) \
V(CmpHoleAndBranch) \
@@ -406,19 +407,32 @@ class LInstructionGap V8_FINAL : public LGap {
};
+class LClobberDoubles V8_FINAL : public LTemplateInstruction<0, 0, 0> {
+ public:
+ LClobberDoubles() { ASSERT(!CpuFeatures::IsSafeForSnapshot(SSE2); }
+
+ virtual bool ClobbersDoubleRegisters() const { return true; }
+
+ DECLARE_CONCRETE_INSTRUCTION(ClobberDoubles, "clobber-d")
+};
+
+
class LGoto V8_FINAL : public LTemplateInstruction<0, 0, 0> {
public:
- explicit LGoto(int block_id) : block_id_(block_id) { }
+ explicit LGoto(HBasicBlock* block) : block_(block) { }
virtual bool HasInterestingComment(LCodeGen* gen) const V8_OVERRIDE;
DECLARE_CONCRETE_INSTRUCTION(Goto, "goto")
virtual void PrintDataTo(StringStream* stream) V8_OVERRIDE;
virtual bool IsControl() const V8_OVERRIDE { return true; }
- int block_id() const { return block_id_; }
+ int block_id() const { return block_->block_id(); }
+ virtual bool ClobbersDoubleRegisters() const { return false; }
+
+ bool jumps_to_join() const { return block_->predecessors()->length() >
1; }
private:
- int block_id_;
+ HBasicBlock* block_;
};
--
--
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