Reviewers: danno, vincent.belliard.arm, Paul Lind, kisg, palfia, dusmil,
Description:
MIPS: sligthly reduce deopt tables size.
Port r22305 (00a3740)
BUG=
Please review this at https://codereview.chromium.org/387473003/
SVN Base: https://v8.googlecode.com/svn/branches/bleeding_edge
Affected files (+64, -35 lines):
M src/mips/deoptimizer-mips.cc
M src/mips/lithium-codegen-mips.cc
Index: src/mips/deoptimizer-mips.cc
diff --git a/src/mips/deoptimizer-mips.cc b/src/mips/deoptimizer-mips.cc
index
5723136c84ecbfb52ebe9ccf9200b53f19736ec2..920900820a30430b41430c9e64b8f02230ee10f9
100644
--- a/src/mips/deoptimizer-mips.cc
+++ b/src/mips/deoptimizer-mips.cc
@@ -320,7 +320,7 @@ void Deoptimizer::EntryGenerator::Generate() {
// Maximum size of a table entry generated below.
-const int Deoptimizer::table_entry_size_ = 7 * Assembler::kInstrSize;
+const int Deoptimizer::table_entry_size_ = 6 * Assembler::kInstrSize;
void Deoptimizer::TableEntryGenerator::GeneratePrologue() {
Assembler::BlockTrampolinePoolScope block_trampoline_pool(masm());
@@ -332,7 +332,6 @@ void
Deoptimizer::TableEntryGenerator::GeneratePrologue() {
for (int i = 0; i < count(); i++) {
Label start;
__ bind(&start);
- __ addiu(sp, sp, -1 * kPointerSize);
// Jump over the remaining deopt entries (including this one).
// This code is always reached by calling Jump, which puts the target
(label
// start) into t9.
@@ -340,8 +339,8 @@ void
Deoptimizer::TableEntryGenerator::GeneratePrologue() {
__ Addu(t9, t9, remaining_entries);
// 'at' was clobbered so we can only load the current entry value here.
__ li(at, i);
- __ jr(t9); // Expose delay slot.
- __ sw(at, MemOperand(sp, 0 * kPointerSize)); // In the delay slot.
+ __ jr(t9);
+ __ nop();
// Pad the rest of the code.
while (table_entry_size_ > (masm()->SizeOfCodeGeneratedSince(&start)))
{
@@ -353,6 +352,7 @@ void
Deoptimizer::TableEntryGenerator::GeneratePrologue() {
ASSERT_EQ(masm()->SizeOfCodeGeneratedSince(&table_start),
count() * table_entry_size_);
+ __ Push(at);
}
Index: src/mips/lithium-codegen-mips.cc
diff --git a/src/mips/lithium-codegen-mips.cc
b/src/mips/lithium-codegen-mips.cc
index
247572abc2eb75b48030069a8e8cdbe4f03d3544..8f224e29a19a3f38cf682365c26ea673c3c94f59
100644
--- a/src/mips/lithium-codegen-mips.cc
+++ b/src/mips/lithium-codegen-mips.cc
@@ -324,45 +324,74 @@ bool LCodeGen::GenerateDeferredCode() {
bool LCodeGen::GenerateDeoptJumpTable() {
if (deopt_jump_table_.length() > 0) {
+ Label needs_frame, call_deopt_entry;
+
Comment(";;; -------------------- Jump table --------------------");
- }
- Assembler::BlockTrampolinePoolScope block_trampoline_pool(masm_);
- Label table_start;
- __ bind(&table_start);
- Label needs_frame;
- for (int i = 0; i < deopt_jump_table_.length(); i++) {
- __ bind(&deopt_jump_table_[i].label);
- Address entry = deopt_jump_table_[i].address;
- Deoptimizer::BailoutType type = deopt_jump_table_[i].bailout_type;
- int id = Deoptimizer::GetDeoptimizationId(isolate(), entry, type);
- if (id == Deoptimizer::kNotDeoptimizationEntry) {
- Comment(";;; jump table entry %d.", i);
- } else {
+ Address base = deopt_jump_table_[0].address;
+
+ Register entry_offset = t9;
+
+ int length = deopt_jump_table_.length();
+ for (int i = 0; i < length; i++) {
+ __ bind(&deopt_jump_table_[i].label);
+
+ Deoptimizer::BailoutType type = deopt_jump_table_[i].bailout_type;
+ ASSERT(type == deopt_jump_table_[0].bailout_type);
+ Address entry = deopt_jump_table_[i].address;
+ int id = Deoptimizer::GetDeoptimizationId(isolate(), entry, type);
+ ASSERT(id != Deoptimizer::kNotDeoptimizationEntry);
Comment(";;; jump table entry %d: deoptimization bailout %d.", i,
id);
- }
- __ li(t9, Operand(ExternalReference::ForDeoptEntry(entry)));
- if (deopt_jump_table_[i].needs_frame) {
- ASSERT(!info()->saves_caller_doubles());
- if (needs_frame.is_bound()) {
- __ Branch(&needs_frame);
+
+ // Second-level deopt table entries are contiguous and small, so
instead
+ // of loading the full, absolute address of each one, load an
immediate
+ // offset which will be added to the base address later.
+ __ li(entry_offset, Operand(entry - base));
+
+ if (deopt_jump_table_[i].needs_frame) {
+ ASSERT(!info()->saves_caller_doubles());
+ if (needs_frame.is_bound()) {
+ __ Branch(&needs_frame);
+ } else {
+ __ bind(&needs_frame);
+ Comment(";;; call deopt with frame");
+ __ MultiPush(cp.bit() | fp.bit() | ra.bit());
+ // This variant of deopt can only be used with stubs. Since we
don't
+ // have a function pointer to install in the stack frame that
we're
+ // building, install a special marker there instead.
+ ASSERT(info()->IsStub());
+ __ li(at, Operand(Smi::FromInt(StackFrame::STUB)));
+ __ push(at);
+ __ Addu(fp, sp,
+ Operand(StandardFrameConstants::kFixedFrameSizeFromFp));
+ __ bind(&call_deopt_entry);
+ // Add the base address to the offset previously loaded in
+ // entry_offset.
+ __ Addu(entry_offset, entry_offset,
+ Operand(ExternalReference::ForDeoptEntry(base)));
+ __ Call(entry_offset);
+ }
} else {
- __ bind(&needs_frame);
- __ MultiPush(cp.bit() | fp.bit() | ra.bit());
- // This variant of deopt can only be used with stubs. Since we
don't
- // have a function pointer to install in the stack frame that we're
- // building, install a special marker there instead.
- ASSERT(info()->IsStub());
- __ li(scratch0(), Operand(Smi::FromInt(StackFrame::STUB)));
- __ push(scratch0());
- __ Addu(fp, sp,
Operand(StandardFrameConstants::kFixedFrameSizeFromFp));
- __ Call(t9);
+ // The last entry can fall through into `call_deopt_entry`,
avoiding a
+ // branch.
+ bool need_branch = ((i + 1) != length) ||
call_deopt_entry.is_bound();
+
+ if (need_branch) __ Branch(&call_deopt_entry);
}
- } else {
+ }
+
+ if (!call_deopt_entry.is_bound()) {
+ Comment(";;; call deopt");
+ __ bind(&call_deopt_entry);
+
if (info()->saves_caller_doubles()) {
ASSERT(info()->IsStub());
RestoreCallerDoubles();
}
- __ Call(t9);
+
+ // Add the base address to the offset previously loaded in
entry_offset.
+ __ Addu(entry_offset, entry_offset,
+ Operand(ExternalReference::ForDeoptEntry(base)));
+ __ Call(entry_offset);
}
}
__ RecordComment("]");
--
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