Revision: 15733
Author: [email protected]
Date: Wed Jul 17 16:57:32 2013
Log: MIPS: Improve code aging sequence.
Port r15697 (61d56196)
Original commit message:
The code aging sequence contains a load which is unecessary for optimised
function. This has been replaced by a nop.
BUG=
Review URL: https://codereview.chromium.org/19683005
http://code.google.com/p/v8/source/detail?r=15733
Modified:
/branches/bleeding_edge/src/mips/assembler-mips.h
/branches/bleeding_edge/src/mips/codegen-mips.cc
/branches/bleeding_edge/src/mips/full-codegen-mips.cc
/branches/bleeding_edge/src/mips/lithium-codegen-mips.cc
=======================================
--- /branches/bleeding_edge/src/mips/assembler-mips.h Tue Apr 16 04:33:02
2013
+++ /branches/bleeding_edge/src/mips/assembler-mips.h Wed Jul 17 16:57:32
2013
@@ -583,7 +583,8 @@
LAST_CODE_MARKER,
FIRST_IC_MARKER = PROPERTY_ACCESS_INLINED,
// Code aging
- CODE_AGE_MARKER_NOP = 6
+ CODE_AGE_MARKER_NOP = 6,
+ CODE_AGE_SEQUENCE_NOP
};
// Type == 0 is the default non-marking nop. For mips this is a
=======================================
--- /branches/bleeding_edge/src/mips/codegen-mips.cc Fri Jul 5 02:52:11
2013
+++ /branches/bleeding_edge/src/mips/codegen-mips.cc Wed Jul 17 16:57:32
2013
@@ -603,7 +603,7 @@
if (!initialized) {
CodePatcher patcher(byte_sequence, kNoCodeAgeSequenceLength);
patcher.masm()->Push(ra, fp, cp, a1);
- patcher.masm()->LoadRoot(at, Heap::kUndefinedValueRootIndex);
+ patcher.masm()->nop(Assembler::CODE_AGE_SEQUENCE_NOP);
patcher.masm()->Addu(fp, sp, Operand(2 * kPointerSize));
initialized = true;
}
=======================================
--- /branches/bleeding_edge/src/mips/full-codegen-mips.cc Wed Jul 17
08:58:59 2013
+++ /branches/bleeding_edge/src/mips/full-codegen-mips.cc Wed Jul 17
16:57:32 2013
@@ -174,9 +174,7 @@
// The following three instructions must remain together and unmodified
for
// code aging to work properly.
__ Push(ra, fp, cp, a1);
- // Load undefined value here, so the value is ready for the loop
- // below.
- __ LoadRoot(at, Heap::kUndefinedValueRootIndex);
+ __ nop(Assembler::CODE_AGE_SEQUENCE_NOP);
// Adjust fp to point to caller's fp.
__ Addu(fp, sp, Operand(2 * kPointerSize));
info->AddNoFrameRange(0, masm_->pc_offset());
@@ -185,8 +183,11 @@
int locals_count = info->scope()->num_stack_slots();
// Generators allocate locals, if any, in context slots.
ASSERT(!info->function()->is_generator() || locals_count == 0);
- for (int i = 0; i < locals_count; i++) {
- __ push(at);
+ if (locals_count > 0) {
+ __ LoadRoot(at, Heap::kUndefinedValueRootIndex);
+ for (int i = 0; i < locals_count; i++) {
+ __ push(at);
+ }
}
}
=======================================
--- /branches/bleeding_edge/src/mips/lithium-codegen-mips.cc Wed Jul 17
11:39:34 2013
+++ /branches/bleeding_edge/src/mips/lithium-codegen-mips.cc Wed Jul 17
16:57:32 2013
@@ -159,9 +159,9 @@
// The following three instructions must remain together and
unmodified
// for code aging to work properly.
__ Push(ra, fp, cp, a1);
- // Add unused load of ip to ensure prologue sequence is identical for
+ // Add unused nop to ensure prologue sequence is identical for
// full-codegen and lithium-codegen.
- __ LoadRoot(at, Heap::kUndefinedValueRootIndex);
+ __ nop(Assembler::CODE_AGE_SEQUENCE_NOP);
// Adj. FP to point to saved FP.
__ Addu(fp, sp, Operand(2 * kPointerSize));
}
--
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