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MIPS: port Simplify handling of exits from with and catch.

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Ported r8922 (5ea2fb5)

Original commit message:
Remove the try/finally used for with and catch. Instead of using
try/finally to handle break and continue from with or catch,
statically track nesting dept and clean up when compiling break or
continue.
And instead of using try/finally to handle throw to handler in a frame
whose pc is inside a with or catch, store the context that the handler
should run in in the handler itself.

BUG=
TEST=

Review URL: http://codereview.chromium.org/7648026
Patch from Paul Lind <plind44@gmail.com>.

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@8936 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
This commit is contained in:
kmillikin@chromium.org 2011-08-16 08:48:45 +00:00
parent 24e6d48d9b
commit 06b8e73b99
2 changed files with 50 additions and 51 deletions
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9
src/mips/frames-mips.h
View File

@ -121,10 +121,11 @@ static const int kSafepointRegisterStackIndexMap[kNumRegs] = {
class StackHandlerConstants : public AllStatic {
public:
static const int kNextOffset = 0 * kPointerSize;
static const int kStateOffset = 1 * kPointerSize;
static const int kFPOffset = 2 * kPointerSize;
static const int kPCOffset = 3 * kPointerSize;
static const int kNextOffset = 0 * kPointerSize;
static const int kStateOffset = 1 * kPointerSize;
static const int kContextOffset = 2 * kPointerSize;
static const int kFPOffset = 3 * kPointerSize;
static const int kPCOffset = 4 * kPointerSize;
static const int kSize = kPCOffset + kPointerSize;
};

92
src/mips/macro-assembler-mips.cc
View File

@ -2244,7 +2244,13 @@ void MacroAssembler::DebugBreak() {
void MacroAssembler::PushTryHandler(CodeLocation try_location,
HandlerType type) {
// Adjust this code if not the case.
ASSERT(StackHandlerConstants::kSize == 4 * kPointerSize);
STATIC_ASSERT(StackHandlerConstants::kSize == 5 * kPointerSize);
STATIC_ASSERT(StackHandlerConstants::kNextOffset == 0 * kPointerSize);
STATIC_ASSERT(StackHandlerConstants::kStateOffset == 1 * kPointerSize);
STATIC_ASSERT(StackHandlerConstants::kContextOffset == 2 * kPointerSize);
STATIC_ASSERT(StackHandlerConstants::kFPOffset == 3 * kPointerSize);
STATIC_ASSERT(StackHandlerConstants::kPCOffset == 4 * kPointerSize);
// The return address is passed in register ra.
if (try_location == IN_JAVASCRIPT) {
if (type == TRY_CATCH_HANDLER) {
@ -2252,19 +2258,16 @@ void MacroAssembler::PushTryHandler(CodeLocation try_location,
} else {
li(t0, Operand(StackHandler::TRY_FINALLY));
}
ASSERT(StackHandlerConstants::kStateOffset == 1 * kPointerSize
&& StackHandlerConstants::kFPOffset == 2 * kPointerSize
&& StackHandlerConstants::kPCOffset == 3 * kPointerSize
&& StackHandlerConstants::kNextOffset == 0 * kPointerSize);
// Save the current handler as the next handler.
li(t2, Operand(ExternalReference(Isolate::k_handler_address, isolate())));
lw(t1, MemOperand(t2));
addiu(sp, sp, -StackHandlerConstants::kSize);
sw(ra, MemOperand(sp, 12));
sw(fp, MemOperand(sp, 8));
sw(t0, MemOperand(sp, 4));
sw(t1, MemOperand(sp, 0));
sw(ra, MemOperand(sp, StackHandlerConstants::kPCOffset));
sw(fp, MemOperand(sp, StackHandlerConstants::kFPOffset));
sw(cp, MemOperand(sp, StackHandlerConstants::kContextOffset));
sw(t0, MemOperand(sp, StackHandlerConstants::kStateOffset));
sw(t1, MemOperand(sp, StackHandlerConstants::kNextOffset));
// Link this handler as the new current one.
sw(sp, MemOperand(t2));
@ -2272,11 +2275,6 @@ void MacroAssembler::PushTryHandler(CodeLocation try_location,
} else {
// Must preserve a0-a3, and s0 (argv).
ASSERT(try_location == IN_JS_ENTRY);
ASSERT(StackHandlerConstants::kStateOffset == 1 * kPointerSize
&& StackHandlerConstants::kFPOffset == 2 * kPointerSize
&& StackHandlerConstants::kPCOffset == 3 * kPointerSize
&& StackHandlerConstants::kNextOffset == 0 * kPointerSize);
// The frame pointer does not point to a JS frame so we save NULL
// for fp. We expect the code throwing an exception to check fp
// before dereferencing it to restore the context.
@ -2286,11 +2284,14 @@ void MacroAssembler::PushTryHandler(CodeLocation try_location,
li(t2, Operand(ExternalReference(Isolate::k_handler_address, isolate())));
lw(t1, MemOperand(t2));
ASSERT(Smi::FromInt(0) == 0); // Used for no context.
addiu(sp, sp, -StackHandlerConstants::kSize);
sw(ra, MemOperand(sp, 12));
sw(zero_reg, MemOperand(sp, 8));
sw(t0, MemOperand(sp, 4));
sw(t1, MemOperand(sp, 0));
sw(ra, MemOperand(sp, StackHandlerConstants::kPCOffset));
sw(zero_reg, MemOperand(sp, StackHandlerConstants::kFPOffset));
sw(zero_reg, MemOperand(sp, StackHandlerConstants::kContextOffset));
sw(t0, MemOperand(sp, StackHandlerConstants::kStateOffset));
sw(t1, MemOperand(sp, StackHandlerConstants::kNextOffset));
// Link this handler as the new current one.
sw(sp, MemOperand(t2));
@ -2299,7 +2300,7 @@ void MacroAssembler::PushTryHandler(CodeLocation try_location,
void MacroAssembler::PopTryHandler() {
ASSERT_EQ(0, StackHandlerConstants::kNextOffset);
STATIC_ASSERT(StackHandlerConstants::kNextOffset == 0);
pop(a1);
Addu(sp, sp, Operand(StackHandlerConstants::kSize - kPointerSize));
li(at, Operand(ExternalReference(Isolate::k_handler_address, isolate())));
@ -2312,28 +2313,31 @@ void MacroAssembler::Throw(Register value) {
Move(v0, value);
// Adjust this code if not the case.
STATIC_ASSERT(StackHandlerConstants::kSize == 4 * kPointerSize);
STATIC_ASSERT(StackHandlerConstants::kSize == 5 * kPointerSize);
STATIC_ASSERT(StackHandlerConstants::kNextOffset == 0 * kPointerSize);
STATIC_ASSERT(StackHandlerConstants::kStateOffset == 1 * kPointerSize);
STATIC_ASSERT(StackHandlerConstants::kContextOffset == 2 * kPointerSize);
STATIC_ASSERT(StackHandlerConstants::kFPOffset == 3 * kPointerSize);
STATIC_ASSERT(StackHandlerConstants::kPCOffset == 4 * kPointerSize);
// Drop the sp to the top of the handler.
li(a3, Operand(ExternalReference(Isolate::k_handler_address,
isolate())));
isolate())));
lw(sp, MemOperand(a3));
// Restore the next handler and frame pointer, discard handler state.
STATIC_ASSERT(StackHandlerConstants::kNextOffset == 0);
// Restore the next handler.
pop(a2);
sw(a2, MemOperand(a3));
STATIC_ASSERT(StackHandlerConstants::kFPOffset == 2 * kPointerSize);
MultiPop(a3.bit() | fp.bit());
// Before returning we restore the context from the frame pointer if
// not NULL. The frame pointer is NULL in the exception handler of a
// JS entry frame.
// Set cp to NULL if fp is NULL.
// Restore context and frame pointer, discard state (a3).
MultiPop(a3.bit() | cp.bit() | fp.bit());
// If the handler is a JS frame, restore the context to the frame.
// (a3 == ENTRY) == (fp == 0) == (cp == 0), so we could test any
// of them.
Label done;
Branch(USE_DELAY_SLOT, &done, eq, fp, Operand(zero_reg));
mov(cp, zero_reg); // In branch delay slot.
lw(cp, MemOperand(fp, StandardFrameConstants::kContextOffset));
Branch(&done, eq, fp, Operand(zero_reg));
sw(cp, MemOperand(fp, StandardFrameConstants::kContextOffset));
bind(&done);
#ifdef DEBUG
@ -2355,7 +2359,6 @@ void MacroAssembler::Throw(Register value) {
}
#endif
STATIC_ASSERT(StackHandlerConstants::kPCOffset == 3 * kPointerSize);
pop(t9); // 2 instructions: lw, add sp.
Jump(t9); // 2 instructions: jr, nop (in delay slot).
@ -2370,7 +2373,12 @@ void MacroAssembler::Throw(Register value) {
void MacroAssembler::ThrowUncatchable(UncatchableExceptionType type,
Register value) {
// Adjust this code if not the case.
STATIC_ASSERT(StackHandlerConstants::kSize == 4 * kPointerSize);
STATIC_ASSERT(StackHandlerConstants::kSize == 5 * kPointerSize);
STATIC_ASSERT(StackHandlerConstants::kNextOffset == 0 * kPointerSize);
STATIC_ASSERT(StackHandlerConstants::kStateOffset == 1 * kPointerSize);
STATIC_ASSERT(StackHandlerConstants::kContextOffset == 2 * kPointerSize);
STATIC_ASSERT(StackHandlerConstants::kFPOffset == 3 * kPointerSize);
STATIC_ASSERT(StackHandlerConstants::kPCOffset == 4 * kPointerSize);
// v0 is expected to hold the exception.
Move(v0, value);
@ -2393,7 +2401,6 @@ void MacroAssembler::ThrowUncatchable(UncatchableExceptionType type,
bind(&done);
// Set the top handler address to next handler past the current ENTRY handler.
STATIC_ASSERT(StackHandlerConstants::kNextOffset == 0);
pop(a2);
sw(a2, MemOperand(a3));
@ -2415,20 +2422,12 @@ void MacroAssembler::ThrowUncatchable(UncatchableExceptionType type,
// Stack layout at this point. See also StackHandlerConstants.
// sp -> state (ENTRY)
// cp
// fp
// ra
// Discard handler state (a2 is not used) and restore frame pointer.
STATIC_ASSERT(StackHandlerConstants::kFPOffset == 2 * kPointerSize);
MultiPop(a2.bit() | fp.bit()); // a2: discarded state.
// Before returning we restore the context from the frame pointer if
// not NULL. The frame pointer is NULL in the exception handler of a
// JS entry frame.
Label cp_null;
Branch(USE_DELAY_SLOT, &cp_null, eq, fp, Operand(zero_reg));
mov(cp, zero_reg); // In the branch delay slot.
lw(cp, MemOperand(fp, StandardFrameConstants::kContextOffset));
bind(&cp_null);
// Restore context and frame pointer, discard state (r2).
MultiPop(a2.bit() | cp.bit() | fp.bit());
#ifdef DEBUG
// When emitting debug_code, set ra as return address for the jump.
@ -2448,7 +2447,6 @@ void MacroAssembler::ThrowUncatchable(UncatchableExceptionType type,
addiu(ra, ra, kOffsetRaBytes);
}
#endif
STATIC_ASSERT(StackHandlerConstants::kPCOffset == 3 * kPointerSize);
pop(t9); // 2 instructions: lw, add sp.
Jump(t9); // 2 instructions: jr, nop (in delay slot).