Reviewers: danno, Paul Lind, kisg,
Description:
MIPS: Simplify the deopt entry method.
The t9 register will always hold the address of the current entry when
deoptimizing,
so it can be used as the basis of calculation.
BUG=
TEST=
Please review this at http://codereview.chromium.org/9546017/
Affected files:
M src/mips/deoptimizer-mips.cc
Index: src/mips/deoptimizer-mips.cc
diff --git a/src/mips/deoptimizer-mips.cc b/src/mips/deoptimizer-mips.cc
index
7e0a53a08d1dc802a238e58f83a715a82f8318f6..611fbaaf96511f9c2666f7f287ea4ed718d221e5
100644
--- a/src/mips/deoptimizer-mips.cc
+++ b/src/mips/deoptimizer-mips.cc
@@ -941,7 +941,7 @@ void Deoptimizer::EntryGenerator::Generate() {
// Maximum size of a table entry generated below.
-const int Deoptimizer::table_entry_size_ = 12 * Assembler::kInstrSize;
+const int Deoptimizer::table_entry_size_ = 9 * Assembler::kInstrSize;
void Deoptimizer::TableEntryGenerator::GeneratePrologue() {
Assembler::BlockTrampolinePoolScope block_trampoline_pool(masm());
@@ -955,29 +955,20 @@ void
Deoptimizer::TableEntryGenerator::GeneratePrologue() {
__ bind(&start);
if (type() != EAGER) {
// Emulate ia32 like call by pushing return address to stack.
- __ addiu(sp, sp, -3 * kPointerSize);
- __ sw(ra, MemOperand(sp, 2 * kPointerSize));
- } else {
__ addiu(sp, sp, -2 * kPointerSize);
+ __ sw(ra, MemOperand(sp, 1 * kPointerSize));
+ } else {
+ __ addiu(sp, sp, -1 * kPointerSize);
}
- // Using ori makes sure only one instruction is generated. This will
work
- // as long as the number of deopt entries is below 2^16.
- __ ori(at, zero_reg, i);
- __ sw(at, MemOperand(sp, kPointerSize));
- __ sw(ra, MemOperand(sp, 0));
- // This branch instruction only jumps over one instruction, and that is
- // executed in the delay slot. The result is that execution is linear
but
- // the ra register is updated.
- __ bal(1);
// Jump over the remaining deopt entries (including this one).
- // Only include the remaining part of the current entry in the
calculation.
+ // This code is always reached by calling Jump, which puts the target
(label
+ // start) into t9.
const int remaining_entries = (count() - i) * table_entry_size_;
- const int cur_size = masm()->SizeOfCodeGeneratedSince(&start);
- // ra points to the instruction after the delay slot. Adjust by 4.
- __ Addu(at, ra, remaining_entries - cur_size - Assembler::kInstrSize);
- __ lw(ra, MemOperand(sp, 0));
- __ jr(at); // Expose delay slot.
- __ addiu(sp, sp, kPointerSize); // In delay slot.
+ __ 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.
// Pad the rest of the code.
while (table_entry_size_ > (masm()->SizeOfCodeGeneratedSince(&start)))
{
--
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