MIPS: Add a level of indirection to exception handler addresses.
Port r9977 (9aded78be4). Note: This is the port of the reapplied patch, not the original. Original commit message: To support deoptimization of exception handlers, the handler address in the stack is converted to a pair of code object and an index into a separate table of code offsets. The index part is invariant under deoptimization. The index is packed into the handler state field so that handler size does not change. BUG= TEST= Review URL: http://codereview.chromium.org/8557003 Patch from Gergely Kis <gergely@homejinni.com>. git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@10039 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
This commit is contained in:
kmillikin@chromium.org
parent
561b5716d7
commit
29b5ceb897
@ -3856,7 +3856,7 @@ void CEntryStub::Generate(MacroAssembler* masm) {
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void JSEntryStub::GenerateBody(MacroAssembler* masm, bool is_construct) {
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Label invoke, exit;
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Label invoke, handler_entry, exit;
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Isolate* isolate = masm->isolate();
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// Registers:
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@ -3933,14 +3933,15 @@ void JSEntryStub::GenerateBody(MacroAssembler* masm, bool is_construct) {
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__ bind(&cont);
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__ push(t0);
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// Call a faked try-block that does the invoke.
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__ bal(&invoke); // bal exposes branch delay slot.
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__ nop(); // Branch delay slot nop.
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// Caught exception: Store result (exception) in the pending
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// exception field in the JSEnv and return a failure sentinel.
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// Coming in here the fp will be invalid because the PushTryHandler below
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// sets it to 0 to signal the existence of the JSEntry frame.
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// Jump to a faked try block that does the invoke, with a faked catch
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// block that sets the pending exception.
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__ jmp(&invoke);
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__ bind(&handler_entry);
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handler_offset_ = handler_entry.pos();
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// Caught exception: Store result (exception) in the pending exception
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// field in the JSEnv and return a failure sentinel. Coming in here the
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// fp will be invalid because the PushTryHandler below sets it to 0 to
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// signal the existence of the JSEntry frame.
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__ li(t0, Operand(ExternalReference(Isolate::kPendingExceptionAddress,
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isolate)));
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__ sw(v0, MemOperand(t0)); // We come back from 'invoke'. result is in v0.
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@ -3948,9 +3949,10 @@ void JSEntryStub::GenerateBody(MacroAssembler* masm, bool is_construct) {
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__ b(&exit); // b exposes branch delay slot.
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__ nop(); // Branch delay slot nop.
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// Invoke: Link this frame into the handler chain.
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// Invoke: Link this frame into the handler chain. There's only one
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// handler block in this code object, so its index is 0.
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__ bind(&invoke);
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__ PushTryHandler(IN_JS_ENTRY, JS_ENTRY_HANDLER);
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__ PushTryHandler(IN_JS_ENTRY, JS_ENTRY_HANDLER, 0);
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// If an exception not caught by another handler occurs, this handler
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// returns control to the code after the bal(&invoke) above, which
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// restores all kCalleeSaved registers (including cp and fp) to their
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@ -5103,7 +5105,7 @@ void RegExpConstructResultStub::Generate(MacroAssembler* masm) {
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}
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void CallFunctionStub::FinishCode(Code* code) {
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void CallFunctionStub::FinishCode(Handle<Code> code) {
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code->set_has_function_cache(false);
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}
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@ -137,7 +137,7 @@ class UnaryOpStub: public CodeStub {
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return UnaryOpIC::ToState(operand_type_);
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}
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virtual void FinishCode(Code* code) {
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virtual void FinishCode(Handle<Code> code) {
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code->set_unary_op_type(operand_type_);
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}
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};
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@ -236,7 +236,7 @@ class BinaryOpStub: public CodeStub {
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return BinaryOpIC::ToState(operands_type_);
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}
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virtual void FinishCode(Code* code) {
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virtual void FinishCode(Handle<Code> code) {
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code->set_binary_op_type(operands_type_);
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code->set_binary_op_result_type(result_type_);
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}
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@ -154,13 +154,13 @@ static const int kSafepointRegisterStackIndexMap[kNumRegs] = {
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class StackHandlerConstants : public AllStatic {
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public:
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static const int kNextOffset = 0 * kPointerSize;
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static const int kStateOffset = 1 * kPointerSize;
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static const int kContextOffset = 2 * kPointerSize;
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static const int kFPOffset = 3 * kPointerSize;
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static const int kPCOffset = 4 * kPointerSize;
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static const int kNextOffset = 0 * kPointerSize;
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static const int kCodeOffset = 1 * kPointerSize;
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static const int kStateOffset = 2 * kPointerSize;
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static const int kContextOffset = 3 * kPointerSize;
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static const int kFPOffset = 4 * kPointerSize;
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static const int kSize = kPCOffset + kPointerSize;
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static const int kSize = kFPOffset + kPointerSize;
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};
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@ -137,6 +137,8 @@ void FullCodeGenerator::Generate(CompilationInfo* info) {
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ASSERT(info_ == NULL);
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info_ = info;
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scope_ = info->scope();
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handler_table_ =
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isolate()->factory()->NewFixedArray(function()->handler_count(), TENURED);
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SetFunctionPosition(function());
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Comment cmnt(masm_, "[ function compiled by full code generator");
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@ -2544,60 +2544,50 @@ void MacroAssembler::DebugBreak() {
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// Exception handling.
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void MacroAssembler::PushTryHandler(CodeLocation try_location,
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HandlerType type) {
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HandlerType type,
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int handler_index) {
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// Adjust this code if not the case.
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STATIC_ASSERT(StackHandlerConstants::kSize == 5 * kPointerSize);
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STATIC_ASSERT(StackHandlerConstants::kNextOffset == 0 * kPointerSize);
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STATIC_ASSERT(StackHandlerConstants::kStateOffset == 1 * kPointerSize);
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STATIC_ASSERT(StackHandlerConstants::kContextOffset == 2 * kPointerSize);
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STATIC_ASSERT(StackHandlerConstants::kFPOffset == 3 * kPointerSize);
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STATIC_ASSERT(StackHandlerConstants::kPCOffset == 4 * kPointerSize);
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STATIC_ASSERT(StackHandlerConstants::kCodeOffset == 1 * kPointerSize);
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STATIC_ASSERT(StackHandlerConstants::kStateOffset == 2 * kPointerSize);
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STATIC_ASSERT(StackHandlerConstants::kContextOffset == 3 * kPointerSize);
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STATIC_ASSERT(StackHandlerConstants::kFPOffset == 4 * kPointerSize);
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// The return address is passed in register ra.
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// For the JSEntry handler, we must preserve a0-a3 and s0.
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// t1-t3 are available. We will build up the handler from the bottom by
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// pushing on the stack. First compute the state.
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unsigned state = StackHandler::OffsetField::encode(handler_index);
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if (try_location == IN_JAVASCRIPT) {
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if (type == TRY_CATCH_HANDLER) {
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li(t0, Operand(StackHandler::TRY_CATCH));
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} else {
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li(t0, Operand(StackHandler::TRY_FINALLY));
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}
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// Save the current handler as the next handler.
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li(t2, Operand(ExternalReference(Isolate::kHandlerAddress, isolate())));
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lw(t1, MemOperand(t2));
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addiu(sp, sp, -StackHandlerConstants::kSize);
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sw(ra, MemOperand(sp, StackHandlerConstants::kPCOffset));
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sw(fp, MemOperand(sp, StackHandlerConstants::kFPOffset));
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sw(cp, MemOperand(sp, StackHandlerConstants::kContextOffset));
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sw(t0, MemOperand(sp, StackHandlerConstants::kStateOffset));
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sw(t1, MemOperand(sp, StackHandlerConstants::kNextOffset));
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// Link this handler as the new current one.
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sw(sp, MemOperand(t2));
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state |= (type == TRY_CATCH_HANDLER)
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? StackHandler::KindField::encode(StackHandler::TRY_CATCH)
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: StackHandler::KindField::encode(StackHandler::TRY_FINALLY);
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} else {
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// Must preserve a0-a3, and s0 (argv).
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ASSERT(try_location == IN_JS_ENTRY);
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// The frame pointer does not point to a JS frame so we save NULL
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// for fp. We expect the code throwing an exception to check fp
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// before dereferencing it to restore the context.
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li(t0, Operand(StackHandler::ENTRY));
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// Save the current handler as the next handler.
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li(t2, Operand(ExternalReference(Isolate::kHandlerAddress, isolate())));
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lw(t1, MemOperand(t2));
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ASSERT(Smi::FromInt(0) == 0); // Used for no context.
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addiu(sp, sp, -StackHandlerConstants::kSize);
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sw(ra, MemOperand(sp, StackHandlerConstants::kPCOffset));
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sw(zero_reg, MemOperand(sp, StackHandlerConstants::kFPOffset));
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sw(zero_reg, MemOperand(sp, StackHandlerConstants::kContextOffset));
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sw(t0, MemOperand(sp, StackHandlerConstants::kStateOffset));
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sw(t1, MemOperand(sp, StackHandlerConstants::kNextOffset));
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// Link this handler as the new current one.
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sw(sp, MemOperand(t2));
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state |= StackHandler::KindField::encode(StackHandler::ENTRY);
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}
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// Set up the code object (t1) and the state (t2) for pushing.
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li(t1, Operand(CodeObject()));
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li(t2, Operand(state));
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// Push the frame pointer, context, state, and code object.
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if (try_location == IN_JAVASCRIPT) {
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MultiPush(t1.bit() | t2.bit() | cp.bit() | fp.bit());
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} else {
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ASSERT_EQ(Smi::FromInt(0), 0);
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// The second zero_reg indicates no context.
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// The first zero_reg is the NULL frame pointer.
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// The operands are reversed to match the order of MultiPush/Pop.
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Push(zero_reg, zero_reg, t2, t1);
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}
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// Link the current handler as the next handler.
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li(t2, Operand(ExternalReference(Isolate::kHandlerAddress, isolate())));
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lw(t1, MemOperand(t2));
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push(t1);
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// Set this new handler as the current one.
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sw(sp, MemOperand(t2));
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}
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@ -2610,19 +2600,36 @@ void MacroAssembler::PopTryHandler() {
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}
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void MacroAssembler::Throw(Register value) {
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// v0 is expected to hold the exception.
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Move(v0, value);
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void MacroAssembler::JumpToHandlerEntry() {
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// Compute the handler entry address and jump to it. The handler table is
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// a fixed array of (smi-tagged) code offsets.
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// v0 = exception, a1 = code object, a2 = state.
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lw(a3, FieldMemOperand(a1, Code::kHandlerTableOffset)); // Handler table.
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Addu(a3, a3, Operand(FixedArray::kHeaderSize - kHeapObjectTag));
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srl(a2, a2, StackHandler::kKindWidth); // Handler index.
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sll(a2, a2, kPointerSizeLog2);
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Addu(a2, a3, a2);
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lw(a2, MemOperand(a2)); // Smi-tagged offset.
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Addu(a1, a1, Operand(Code::kHeaderSize - kHeapObjectTag)); // Code start.
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sra(t9, a2, kSmiTagSize);
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Addu(t9, t9, a1);
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Jump(t9); // Jump.
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}
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void MacroAssembler::Throw(Register value) {
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// Adjust this code if not the case.
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STATIC_ASSERT(StackHandlerConstants::kSize == 5 * kPointerSize);
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STATIC_ASSERT(StackHandlerConstants::kNextOffset == 0 * kPointerSize);
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STATIC_ASSERT(StackHandlerConstants::kStateOffset == 1 * kPointerSize);
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STATIC_ASSERT(StackHandlerConstants::kContextOffset == 2 * kPointerSize);
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STATIC_ASSERT(StackHandlerConstants::kFPOffset == 3 * kPointerSize);
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STATIC_ASSERT(StackHandlerConstants::kPCOffset == 4 * kPointerSize);
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STATIC_ASSERT(StackHandlerConstants::kNextOffset == 0);
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STATIC_ASSERT(StackHandlerConstants::kCodeOffset == 1 * kPointerSize);
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STATIC_ASSERT(StackHandlerConstants::kStateOffset == 2 * kPointerSize);
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STATIC_ASSERT(StackHandlerConstants::kContextOffset == 3 * kPointerSize);
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STATIC_ASSERT(StackHandlerConstants::kFPOffset == 4 * kPointerSize);
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// Drop the sp to the top of the handler.
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// The exception is expected in v0.
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Move(v0, value);
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// Drop the stack pointer to the top of the top handler.
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li(a3, Operand(ExternalReference(Isolate::kHandlerAddress,
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isolate())));
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lw(sp, MemOperand(a3));
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@ -2631,44 +2638,19 @@ void MacroAssembler::Throw(Register value) {
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pop(a2);
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sw(a2, MemOperand(a3));
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// Restore context and frame pointer, discard state (a3).
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MultiPop(a3.bit() | cp.bit() | fp.bit());
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// Get the code object (a1) and state (a2). Restore the context and frame
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// pointer.
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MultiPop(a1.bit() | a2.bit() | cp.bit() | fp.bit());
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// If the handler is a JS frame, restore the context to the frame.
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// (a3 == ENTRY) == (fp == 0) == (cp == 0), so we could test any
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// of them.
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// (kind == ENTRY) == (fp == 0) == (cp == 0), so we could test either fp
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// or cp.
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Label done;
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Branch(&done, eq, fp, Operand(zero_reg));
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Branch(&done, eq, cp, Operand(zero_reg));
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sw(cp, MemOperand(fp, StandardFrameConstants::kContextOffset));
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bind(&done);
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#ifdef DEBUG
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// When emitting debug_code, set ra as return address for the jump.
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// 5 instructions: add: 1, pop: 2, jump: 2.
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const int kOffsetRaInstructions = 5;
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Label find_ra;
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if (emit_debug_code()) {
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// Compute ra for the Jump(t9).
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const int kOffsetRaBytes = kOffsetRaInstructions * Assembler::kInstrSize;
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// This branch-and-link sequence is needed to get the current PC on mips,
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// saved to the ra register. Then adjusted for instruction count.
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bal(&find_ra); // bal exposes branch-delay.
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nop(); // Branch delay slot nop.
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bind(&find_ra);
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addiu(ra, ra, kOffsetRaBytes);
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}
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#endif
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pop(t9); // 2 instructions: lw, add sp.
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Jump(t9); // 2 instructions: jr, nop (in delay slot).
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if (emit_debug_code()) {
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// Make sure that the expected number of instructions were generated.
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ASSERT_EQ(kOffsetRaInstructions,
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InstructionsGeneratedSince(&find_ra));
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}
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JumpToHandlerEntry();
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}
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@ -2677,10 +2659,10 @@ void MacroAssembler::ThrowUncatchable(UncatchableExceptionType type,
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// Adjust this code if not the case.
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STATIC_ASSERT(StackHandlerConstants::kSize == 5 * kPointerSize);
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STATIC_ASSERT(StackHandlerConstants::kNextOffset == 0 * kPointerSize);
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STATIC_ASSERT(StackHandlerConstants::kStateOffset == 1 * kPointerSize);
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STATIC_ASSERT(StackHandlerConstants::kContextOffset == 2 * kPointerSize);
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STATIC_ASSERT(StackHandlerConstants::kFPOffset == 3 * kPointerSize);
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STATIC_ASSERT(StackHandlerConstants::kPCOffset == 4 * kPointerSize);
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STATIC_ASSERT(StackHandlerConstants::kCodeOffset == 1 * kPointerSize);
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STATIC_ASSERT(StackHandlerConstants::kStateOffset == 2 * kPointerSize);
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STATIC_ASSERT(StackHandlerConstants::kContextOffset == 3 * kPointerSize);
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STATIC_ASSERT(StackHandlerConstants::kFPOffset == 4 * kPointerSize);
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// The exception is expected in v0.
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if (type == OUT_OF_MEMORY) {
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@ -2705,26 +2687,27 @@ void MacroAssembler::ThrowUncatchable(UncatchableExceptionType type,
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li(a3, Operand(ExternalReference(Isolate::kHandlerAddress, isolate())));
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lw(sp, MemOperand(a3));
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// Unwind the handlers until the top ENTRY handler is found.
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// Unwind the handlers until the ENTRY handler is found.
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Label fetch_next, check_kind;
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jmp(&check_kind);
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bind(&fetch_next);
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lw(sp, MemOperand(sp, StackHandlerConstants::kNextOffset));
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bind(&check_kind);
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STATIC_ASSERT(StackHandler::ENTRY == 0);
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lw(a2, MemOperand(sp, StackHandlerConstants::kStateOffset));
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Branch(&fetch_next, ne, a2, Operand(StackHandler::ENTRY));
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And(a2, a2, Operand(StackHandler::KindField::kMask));
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Branch(&fetch_next, ne, a2, Operand(zero_reg));
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// Set the top handler address to next handler past the top ENTRY handler.
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pop(a2);
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sw(a2, MemOperand(a3));
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// Clear the context and frame pointer (0 was saved in the handler), and
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// discard the state (a2).
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MultiPop(a2.bit() | cp.bit() | fp.bit());
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// Get the code object (a1) and state (a2). Clear the context and frame
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// pointer (0 was saved in the handler).
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MultiPop(a1.bit() | a2.bit() | cp.bit() | fp.bit());
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pop(t9); // 2 instructions: lw, add sp.
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Jump(t9); // 2 instructions: jr, nop (in delay slot).
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JumpToHandlerEntry();
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}
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@ -843,9 +843,9 @@ class MacroAssembler: public Assembler {
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// Exception handling.
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// Push a new try handler and link into try handler chain.
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// The return address must be passed in register ra.
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// Clobber t0, t1, t2.
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void PushTryHandler(CodeLocation try_location, HandlerType type);
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void PushTryHandler(CodeLocation try_location,
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HandlerType type,
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int handler_index);
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// Unlink the stack handler on top of the stack from the try handler chain.
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// Must preserve the result register.
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@ -1381,6 +1381,10 @@ class MacroAssembler: public Assembler {
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Register bitmap_reg,
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Register mask_reg);
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// Helper for throwing exceptions. Compute a handler address and jump to
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// it. See the implementation for register usage.
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void JumpToHandlerEntry();
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// Compute memory operands for safepoint stack slots.
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static int SafepointRegisterStackIndex(int reg_code);
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MemOperand SafepointRegisterSlot(Register reg);
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