Reviewers: Paul Lind, kisg, kilvadyb, dusmil, danno,
Message:
PTAL.
Description:
MIPS: Fix and simplify code aging.
This commit fixes a lot of test failures that we saw earlier in the
buildbots
(http://build.chromium.org/p/client.v8/builders/V8%20Linux%20-%20mips%20-%20sim/builds/3034/steps/Check/logs/stdio).
In some very rare cases the code age stub address can be 0xXXXX0000 and in
this
case the li maco instruction emits only 1 instruction (instead of the
expected
2). Thus the code age sequence will be 6 instructions long instead of 7,
which
breaks the code aging feature. This change makes sure that li always emits 2
instructions and it also simplifies the code aging sequence.
Also fixes a small mistake in the simulator at the jalr instruction.
BUG=
Please review this at https://codereview.chromium.org/83583003/
SVN Base: https://v8.googlecode.com/svn/branches/bleeding_edge
Affected files (+33, -34 lines):
M src/mips/assembler-mips-inl.h
M src/mips/builtins-mips.cc
M src/mips/codegen-mips.cc
M src/mips/macro-assembler-mips.cc
M src/mips/simulator-mips.h
M src/mips/simulator-mips.cc
Index: src/mips/assembler-mips-inl.h
diff --git a/src/mips/assembler-mips-inl.h b/src/mips/assembler-mips-inl.h
index
d5af5b2ec6d2521ea85a3a7129ad4a108874e68f..514b3aaa4f00247abdf680935b18edaedcbe3efc
100644
--- a/src/mips/assembler-mips-inl.h
+++ b/src/mips/assembler-mips-inl.h
@@ -260,16 +260,14 @@ Handle<Object>
RelocInfo::code_age_stub_handle(Assembler* origin) {
Code* RelocInfo::code_age_stub() {
ASSERT(rmode_ == RelocInfo::CODE_AGE_SEQUENCE);
return Code::GetCodeFromTargetAddress(
- Memory::Address_at(pc_ + Assembler::kInstrSize *
- (kNoCodeAgeSequenceLength - 1)));
+ Assembler::target_address_at(pc_ + Assembler::kInstrSize));
}
void RelocInfo::set_code_age_stub(Code* stub) {
ASSERT(rmode_ == RelocInfo::CODE_AGE_SEQUENCE);
- Memory::Address_at(pc_ + Assembler::kInstrSize *
- (kNoCodeAgeSequenceLength - 1)) =
- stub->instruction_start();
+ Assembler::set_target_address_at(pc_ + Assembler::kInstrSize,
+ stub->instruction_start());
}
Index: src/mips/builtins-mips.cc
diff --git a/src/mips/builtins-mips.cc b/src/mips/builtins-mips.cc
index
d2641df6e675dcc5f08d4812874e723a493bc80a..19f3cdf4ff81bc837b7ba0958f2da6a63118ee90
100644
--- a/src/mips/builtins-mips.cc
+++ b/src/mips/builtins-mips.cc
@@ -813,12 +813,9 @@ static void
GenerateMakeCodeYoungAgainCommon(MacroAssembler* masm) {
// internal frame to make the code faster, since we shouldn't have to do
stack
// crawls in MakeCodeYoung. This seems a bit fragile.
- __ mov(a0, ra);
- // Adjust a0 to point to the head of the PlatformCodeAge sequence
+ // Set a0 to point to the head of the PlatformCodeAge sequence.
__ Subu(a0, a0,
Operand((kNoCodeAgeSequenceLength - 1) * Assembler::kInstrSize));
- // Restore the original return address of the function
- __ mov(ra, at);
// The following registers must be saved and restored when calling
through to
// the runtime:
@@ -855,12 +852,9 @@ void
Builtins::Generate_MarkCodeAsExecutedOnce(MacroAssembler* masm) {
// save/restore the registers without worrying about which of them
contain
// pointers.
- __ mov(a0, ra);
- // Adjust a0 to point to the head of the PlatformCodeAge sequence
+ // Set a0 to point to the head of the PlatformCodeAge sequence.
__ Subu(a0, a0,
Operand((kNoCodeAgeSequenceLength - 1) * Assembler::kInstrSize));
- // Restore the original return address of the function
- __ mov(ra, at);
// The following registers must be saved and restored when calling
through to
// the runtime:
Index: src/mips/codegen-mips.cc
diff --git a/src/mips/codegen-mips.cc b/src/mips/codegen-mips.cc
index
221a0e1b4e2a81e01bc6cf5a93fdd0007d2b8469..3a87c5af88658b9c848e8c56aeafe7e46a87c76f
100644
--- a/src/mips/codegen-mips.cc
+++ b/src/mips/codegen-mips.cc
@@ -642,8 +642,8 @@ void Code::GetCodeAgeAndParity(byte* sequence, Age* age,
*age = kNoAgeCodeAge;
*parity = NO_MARKING_PARITY;
} else {
- Address target_address = Memory::Address_at(
- sequence + Assembler::kInstrSize * (kNoCodeAgeSequenceLength - 1));
+ Address target_address = Assembler::target_address_at(
+ sequence + Assembler::kInstrSize);
Code* stub = GetCodeFromTargetAddress(target_address);
GetCodeAgeAndParity(stub, age, parity);
}
@@ -662,17 +662,18 @@ void Code::PatchPlatformCodeAge(Isolate* isolate,
} else {
Code* stub = GetCodeAgeStub(isolate, age, parity);
CodePatcher patcher(sequence, young_length / Assembler::kInstrSize);
- // Mark this code sequence for FindPlatformCodeAgeSequence()
+ // Mark this code sequence for FindPlatformCodeAgeSequence().
patcher.masm()->nop(Assembler::CODE_AGE_MARKER_NOP);
- // Save the function's original return address
- // (it will be clobbered by Call(t9))
- patcher.masm()->mov(at, ra);
- // Load the stub address to t9 and call it
- patcher.masm()->li(t9,
- Operand(reinterpret_cast<uint32_t>(stub->instruction_start())));
- patcher.masm()->Call(t9);
- // Record the stub address in the empty space for GetCodeAgeAndParity()
- patcher.masm()->emit_code_stub_address(stub);
+ // Load the stub address to t9 and call it,
+ // GetCodeAgeAndParity() extracts the stub address from this
instruction.
+ patcher.masm()->li(
+ t9,
+ Operand(reinterpret_cast<uint32_t>(stub->instruction_start())),
+ CONSTANT_SIZE);
+ patcher.masm()->nop(); // Prevent jalr to jal optimization.
+ patcher.masm()->jalr(t9, a0);
+ patcher.masm()->nop(); // Branch delay slot nop.
+ patcher.masm()->nop(); // Pad the empty space.
}
}
Index: src/mips/macro-assembler-mips.cc
diff --git a/src/mips/macro-assembler-mips.cc
b/src/mips/macro-assembler-mips.cc
index
cb336f3b0b9262b3c2d12628bec9ec9679a43799..cdfbae39c2a27242f7745cc9cd5d039d11060428
100644
--- a/src/mips/macro-assembler-mips.cc
+++ b/src/mips/macro-assembler-mips.cc
@@ -4526,15 +4526,15 @@ void MacroAssembler::Prologue(PrologueFrameMode
frame_mode) {
// Pre-age the code.
Code* stub = Code::GetPreAgedCodeAgeStub(isolate());
nop(Assembler::CODE_AGE_MARKER_NOP);
- // Save the function's original return address
- // (it will be clobbered by Call(t9)).
- mov(at, ra);
- // Load the stub address to t9 and call it.
+ // Load the stub address to t9 and call it,
+ // GetCodeAgeAndParity() extracts the stub address from this
instruction.
li(t9,
- Operand(reinterpret_cast<uint32_t>(stub->instruction_start())));
- Call(t9);
- // Record the stub address in the empty space for
GetCodeAgeAndParity().
- emit_code_stub_address(stub);
+ Operand(reinterpret_cast<uint32_t>(stub->instruction_start())),
+ CONSTANT_SIZE);
+ nop(); // Prevent jalr to jal optimization.
+ jalr(t9, a0);
+ nop(); // Branch delay slot nop.
+ nop(); // Pad the empty space.
} else {
Push(ra, fp, cp, a1);
nop(Assembler::CODE_AGE_SEQUENCE_NOP);
Index: src/mips/simulator-mips.cc
diff --git a/src/mips/simulator-mips.cc b/src/mips/simulator-mips.cc
index
5a96efe9c1d529338f10b6a0e657804d74e59ce8..acc65251e23f97973d991c65f4078385cec56c14
100644
--- a/src/mips/simulator-mips.cc
+++ b/src/mips/simulator-mips.cc
@@ -1722,6 +1722,7 @@ void Simulator::ConfigureTypeRegister(Instruction*
instr,
int64_t& i64hilo,
uint64_t& u64hilo,
int32_t& next_pc,
+ int32_t& return_addr_reg,
bool& do_interrupt) {
// Every local variable declared here needs to be const.
// This is to make sure that changed values are sent back to
@@ -1782,6 +1783,7 @@ void Simulator::ConfigureTypeRegister(Instruction*
instr,
case JR:
case JALR:
next_pc = get_register(instr->RsValue());
+ return_addr_reg = instr->RdValue();
break;
case SLL:
alu_out = rt << sa;
@@ -1986,6 +1988,7 @@ void Simulator::DecodeTypeRegister(Instruction*
instr) {
int32_t current_pc = get_pc();
// Next pc
int32_t next_pc = 0;
+ int32_t return_addr_reg = 31;
// Set up the variables if needed before executing the instruction.
ConfigureTypeRegister(instr,
@@ -1993,6 +1996,7 @@ void Simulator::DecodeTypeRegister(Instruction*
instr) {
i64hilo,
u64hilo,
next_pc,
+ return_addr_reg,
do_interrupt);
// ---------- Raise exceptions triggered.
@@ -2258,7 +2262,8 @@ void Simulator::DecodeTypeRegister(Instruction*
instr) {
Instruction* branch_delay_instr = reinterpret_cast<Instruction*>(
current_pc+Instruction::kInstrSize);
BranchDelayInstructionDecode(branch_delay_instr);
- set_register(31, current_pc + 2 * Instruction::kInstrSize);
+ set_register(return_addr_reg,
+ current_pc + 2 * Instruction::kInstrSize);
set_pc(next_pc);
pc_modified_ = true;
break;
Index: src/mips/simulator-mips.h
diff --git a/src/mips/simulator-mips.h b/src/mips/simulator-mips.h
index
601cd6d99d113c867419fac06ffdcbc3de5f938c..d9fd10f245c3617e332bfdefeb8b9b3b2a099826
100644
--- a/src/mips/simulator-mips.h
+++ b/src/mips/simulator-mips.h
@@ -289,6 +289,7 @@ class Simulator {
int64_t& i64hilo,
uint64_t& u64hilo,
int32_t& next_pc,
+ int32_t& return_addr_reg,
bool& do_interrupt);
void DecodeTypeImmediate(Instruction* instr);
--
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