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Move stack check into AllocateStackSlots so the load delay can be

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interleaved with other instructions.  Reorder the stack check
slightly to avoid some load delay. The end result is almost
imperceptible.
Review URL: http://codereview.chromium.org/181019

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@2784 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
This commit is contained in:
erik.corry@gmail.com 2009-08-31 10:38:00 +00:00
parent 369214c159
commit fcf8293df2
2 changed files with 33 additions and 7 deletions
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17
src/arm/codegen-arm.cc
View File

@ -176,7 +176,8 @@ void CodeGenerator::GenCode(FunctionLiteral* fun) {
}
#endif
// Allocate space for locals and initialize them.
// Allocate space for locals and initialize them. This also checks
// for stack overflow.
frame_->AllocateStackSlots();
// Initialize the function return target after the locals are set
// up, because it needs the expected frame height from the frame.
@ -278,7 +279,6 @@ void CodeGenerator::GenCode(FunctionLiteral* fun) {
frame_->CallRuntime(Runtime::kTraceEnter, 0);
// Ignore the return value.
}
CheckStack();
// Compile the body of the function in a vanilla state. Don't
// bother compiling all the code if the scope has an illegal
@ -1111,9 +1111,18 @@ void CodeGenerator::CheckStack() {
if (FLAG_check_stack) {
Comment cmnt(masm_, "[ check stack");
__ LoadRoot(ip, Heap::kStackLimitRootIndex);
__ cmp(sp, Operand(ip));
// Put the lr setup instruction in the delay slot. The 'sizeof(Instr)' is
// added to the implicit 8 byte offset that always applies to operations
// with pc and gives a return address 12 bytes down.
masm_->add(lr, pc, Operand(sizeof(Instr)));
masm_->cmp(sp, Operand(ip));
StackCheckStub stub;
__ CallStub(&stub, lo); // Call the stub if lower.
// Call the stub if lower.
masm_->mov(pc,
Operand(reinterpret_cast<intptr_t>(stub.GetCode().location()),
RelocInfo::CODE_TARGET),
LeaveCC,
lo);
}
}

23
src/arm/virtual-frame-arm.cc
View File

@ -141,9 +141,26 @@ void VirtualFrame::AllocateStackSlots() {
Adjust(count);
// Initialize stack slots with 'undefined' value.
__ LoadRoot(ip, Heap::kUndefinedValueRootIndex);
for (int i = 0; i < count; i++) {
__ push(ip);
}
}
if (FLAG_check_stack) {
__ LoadRoot(r2, Heap::kStackLimitRootIndex);
}
for (int i = 0; i < count; i++) {
__ push(ip);
}
if (FLAG_check_stack) {
// Put the lr setup instruction in the delay slot. The 'sizeof(Instr)' is
// added to the implicit 8 byte offset that always applies to operations
// with pc and gives a return address 12 bytes down.
masm()->add(lr, pc, Operand(sizeof(Instr)));
masm()->cmp(sp, Operand(r2));
StackCheckStub stub;
// Call the stub if lower.
masm()->mov(pc,
Operand(reinterpret_cast<intptr_t>(stub.GetCode().location()),
RelocInfo::CODE_TARGET),
LeaveCC,
lo);
}
}