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Unified Diff: src/arm/macro-assembler-arm.cc

Issue 8462010: Add a level of indirection to exception handler addresses. (Closed) Base URL: https://v8.googlecode.com/svn/branches/bleeding_edge
Patch Set: Incorporate review changes. Created 9 years, 1 month ago
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Index: src/arm/macro-assembler-arm.cc
diff --git a/src/arm/macro-assembler-arm.cc b/src/arm/macro-assembler-arm.cc
index 0a10b50aa1a5bf3f9cff73a1f77c3e12d36ef8cc..4fc3b03abf1caced7e8009593a8c24aaeee1cdb4 100644
--- a/src/arm/macro-assembler-arm.cc
+++ b/src/arm/macro-assembler-arm.cc
@@ -1167,46 +1167,48 @@ void MacroAssembler::DebugBreak() {
void MacroAssembler::PushTryHandler(CodeLocation try_location,
- HandlerType type) {
+ HandlerType type,
+ int handler_index) {
// Adjust this code if not the case.
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 pc (return address) is passed in register lr.
+ STATIC_ASSERT(StackHandlerConstants::kCodeOffset == 1 * kPointerSize);
+ STATIC_ASSERT(StackHandlerConstants::kStateOffset == 2 * kPointerSize);
+ STATIC_ASSERT(StackHandlerConstants::kContextOffset == 3 * kPointerSize);
+ STATIC_ASSERT(StackHandlerConstants::kFPOffset == 4 * kPointerSize);
+
+ // For the JSEntry handler, we must preserve r0-r4, r5-r7 are available.
+ // We will build up the handler from the bottom by pushing on the stack.
+ // First compute the state.
+ unsigned state = StackHandler::OffsetField::encode(handler_index);
if (try_location == IN_JAVASCRIPT) {
- if (type == TRY_CATCH_HANDLER) {
- mov(r3, Operand(StackHandler::TRY_CATCH));
- } else {
- mov(r3, Operand(StackHandler::TRY_FINALLY));
- }
- stm(db_w, sp, r3.bit() | cp.bit() | fp.bit() | lr.bit());
- // Save the current handler as the next handler.
- mov(r3, Operand(ExternalReference(Isolate::kHandlerAddress, isolate())));
- ldr(r1, MemOperand(r3));
- push(r1);
- // Link this handler as the new current one.
- str(sp, MemOperand(r3));
+ state |= (type == TRY_CATCH_HANDLER)
+ ? StackHandler::KindField::encode(StackHandler::TRY_CATCH)
+ : StackHandler::KindField::encode(StackHandler::TRY_FINALLY);
} else {
- // Must preserve r0-r4, r5-r7 are available.
ASSERT(try_location == IN_JS_ENTRY);
- // 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.
- mov(r5, Operand(StackHandler::ENTRY)); // State.
- mov(r6, Operand(Smi::FromInt(0))); // Indicates no context.
- mov(r7, Operand(0, RelocInfo::NONE)); // NULL frame pointer.
- stm(db_w, sp, r5.bit() | r6.bit() | r7.bit() | lr.bit());
- // Save the current handler as the next handler.
- mov(r7, Operand(ExternalReference(Isolate::kHandlerAddress, isolate())));
- ldr(r6, MemOperand(r7));
- push(r6);
- // Link this handler as the new current one.
- str(sp, MemOperand(r7));
+ state |= StackHandler::KindField::encode(StackHandler::ENTRY);
+ }
+
+ // Set up the code object (r5) and the state (r6) for pushing.
+ mov(r5, Operand(CodeObject()));
+ mov(r6, Operand(state));
+
+ // Push the frame pointer, context, state, and code object.
+ if (try_location == IN_JAVASCRIPT) {
+ stm(db_w, sp, r5.bit() | r6.bit() | cp.bit() | fp.bit());
+ } else {
+ mov(r7, Operand(Smi::FromInt(0))); // Indicates no context.
+ mov(ip, Operand(0, RelocInfo::NONE)); // NULL frame pointer.
+ stm(db_w, sp, r5.bit() | r6.bit() | r7.bit() | ip.bit());
}
+
+ // Link the current handler as the next handler.
+ mov(r6, Operand(ExternalReference(Isolate::kHandlerAddress, isolate())));
+ ldr(r5, MemOperand(r6));
+ push(r5);
+ // Set this new handler as the current one.
+ str(sp, MemOperand(r6));
}
@@ -1219,42 +1221,50 @@ void MacroAssembler::PopTryHandler() {
}
+void MacroAssembler::JumpToHandlerEntry() {
+ // Compute the handler entry address and jump to it. The handler table is
+ // a fixed array of (smi-tagged) code offsets.
+ // r0 = exception, r1 = code object, r2 = state.
+ ldr(r3, FieldMemOperand(r1, Code::kHandlerTableOffset)); // Handler table.
+ add(r3, r3, Operand(FixedArray::kHeaderSize - kHeapObjectTag));
+ mov(r2, Operand(r2, LSR, StackHandler::kKindWidth)); // Handler index.
+ ldr(r2, MemOperand(r3, r2, LSL, kPointerSizeLog2)); // Smi-tagged offset.
+ add(r1, r1, Operand(Code::kHeaderSize - kHeapObjectTag)); // Code start.
+ add(pc, r1, Operand(r2, ASR, kSmiTagSize)); // Jump.
+}
+
+
void MacroAssembler::Throw(Register value) {
// Adjust this code if not the case.
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);
- // r0 is expected to hold the exception.
+ STATIC_ASSERT(StackHandlerConstants::kNextOffset == 0);
+ STATIC_ASSERT(StackHandlerConstants::kCodeOffset == 1 * kPointerSize);
+ STATIC_ASSERT(StackHandlerConstants::kStateOffset == 2 * kPointerSize);
+ STATIC_ASSERT(StackHandlerConstants::kContextOffset == 3 * kPointerSize);
+ STATIC_ASSERT(StackHandlerConstants::kFPOffset == 4 * kPointerSize);
+
+ // The exception is expected in r0.
if (!value.is(r0)) {
mov(r0, value);
}
-
- // Drop the sp to the top of the handler.
+ // Drop the stack pointer to the top of the top handler.
mov(r3, Operand(ExternalReference(Isolate::kHandlerAddress, isolate())));
ldr(sp, MemOperand(r3));
-
// Restore the next handler.
pop(r2);
str(r2, MemOperand(r3));
- // Restore context and frame pointer, discard state (r3).
- ldm(ia_w, sp, r3.bit() | cp.bit() | fp.bit());
+ // Get the code object (r1) and state (r2). Restore the context and frame
+ // pointer.
+ ldm(ia_w, sp, r1.bit() | r2.bit() | cp.bit() | fp.bit());
// If the handler is a JS frame, restore the context to the frame.
- // (r3 == ENTRY) == (fp == 0) == (cp == 0), so we could test any
- // of them.
- cmp(r3, Operand(StackHandler::ENTRY));
+ // (kind == ENTRY) == (fp == 0) == (cp == 0), so we could test either fp
+ // or cp.
+ tst(cp, cp);
str(cp, MemOperand(fp, StandardFrameConstants::kContextOffset), ne);
-#ifdef DEBUG
- if (emit_debug_code()) {
- mov(lr, Operand(pc));
- }
-#endif
- pop(pc);
+ JumpToHandlerEntry();
}
@@ -1263,10 +1273,10 @@ void MacroAssembler::ThrowUncatchable(UncatchableExceptionType type,
// Adjust this code if not the case.
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);
+ STATIC_ASSERT(StackHandlerConstants::kCodeOffset == 1 * kPointerSize);
+ STATIC_ASSERT(StackHandlerConstants::kStateOffset == 2 * kPointerSize);
+ STATIC_ASSERT(StackHandlerConstants::kContextOffset == 3 * kPointerSize);
+ STATIC_ASSERT(StackHandlerConstants::kFPOffset == 4 * kPointerSize);
// The exception is expected in r0.
if (type == OUT_OF_MEMORY) {
@@ -1291,26 +1301,26 @@ void MacroAssembler::ThrowUncatchable(UncatchableExceptionType type,
mov(r3, Operand(ExternalReference(Isolate::kHandlerAddress, isolate())));
ldr(sp, MemOperand(r3));
- // Unwind the handlers until the top ENTRY handler is found.
+ // Unwind the handlers until the ENTRY handler is found.
Label fetch_next, check_kind;
jmp(&check_kind);
bind(&fetch_next);
ldr(sp, MemOperand(sp, StackHandlerConstants::kNextOffset));
bind(&check_kind);
+ STATIC_ASSERT(StackHandler::ENTRY == 0);
ldr(r2, MemOperand(sp, StackHandlerConstants::kStateOffset));
- cmp(r2, Operand(StackHandler::ENTRY));
+ tst(r2, Operand(StackHandler::KindField::kMask));
b(ne, &fetch_next);
// Set the top handler address to next handler past the top ENTRY handler.
pop(r2);
str(r2, MemOperand(r3));
+ // Get the code object (r1) and state (r2). Clear the context and frame
+ // pointer (0 was saved in the handler).
+ ldm(ia_w, sp, r1.bit() | r2.bit() | cp.bit() | fp.bit());
- // Clear the context and frame pointer (0 was saved in the handler), and
- // discard the state (r2).
- ldm(ia_w, sp, r2.bit() | cp.bit() | fp.bit());
-
- pop(pc);
+ JumpToHandlerEntry();
}
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