Abstract out fetching of break_address in debug mode

If the platform has a variable length call sequence
more than simple offset math is required. This can
be true with out of line constant pools on PowerPC.

BUG=
R=yangguo@chromium.org

Review URL: https://codereview.chromium.org/427863003

Patch from Andrew Low <andrew_low@ca.ibm.com>.

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@22935 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

src/arm/assembler-arm-inl.h

@@ -458,6 +458,11 @@ Address Assembler::target_address_from_return_address(Address pc) {
 }
 
 
+Address Assembler::break_address_from_return_address(Address pc) {
+  return pc - Assembler::kPatchDebugBreakSlotReturnOffset;
+}
+
+
 Address Assembler::return_address_from_call_start(Address pc) {
   if (IsLdrPcImmediateOffset(Memory::int32_at(pc)) |
       IsLdrPpImmediateOffset(Memory::int32_at(pc))) {

src/arm/assembler-arm.h

@@ -781,6 +781,9 @@ class Assembler : public AssemblerBase {
   // in the instruction stream that the call will return from.
   INLINE(static Address return_address_from_call_start(Address pc));
 
+  // Return the code target address of the patch debug break slot
+  INLINE(static Address break_address_from_return_address(Address pc));
+
   // This sets the branch destination (which is in the constant pool on ARM).
   // This is for calls and branches within generated code.
   inline static void deserialization_set_special_target_at(

src/arm64/assembler-arm64-inl.h

@@ -607,6 +607,11 @@ Address Assembler::target_address_from_return_address(Address pc) {
 }
 
 
+Address Assembler::break_address_from_return_address(Address pc) {
+  return pc - Assembler::kPatchDebugBreakSlotReturnOffset;
+}
+
+
 Address Assembler::return_address_from_call_start(Address pc) {
   // The call, generated by MacroAssembler::Call, is one of two possible
   // sequences:

src/arm64/assembler-arm64.h

@@ -887,6 +887,9 @@ class Assembler : public AssemblerBase {
   // instruction stream that call will return from.
   inline static Address return_address_from_call_start(Address pc);
 
+  // Return the code target address of the patch debug break slot
+  inline static Address break_address_from_return_address(Address pc);
+
   // This sets the branch destination (which is in the constant pool on ARM).
   // This is for calls and branches within generated code.
   inline static void deserialization_set_special_target_at(

src/debug.cc

@@ -2326,7 +2326,7 @@ void Debug::SetAfterBreakTarget(JavaScriptFrame* frame) {
   // Find the call address in the running code. This address holds the call to
   // either a DebugBreakXXX or to the debug break return entry code if the
   // break point is still active after processing the break point.
-  Address addr = frame->pc() - Assembler::kPatchDebugBreakSlotReturnOffset;
+  Address addr = Assembler::break_address_from_return_address(frame->pc());
 
   // Check if the location is at JS exit or debug break slot.
   bool at_js_return = false;
@@ -2417,7 +2417,7 @@ bool Debug::IsBreakAtReturn(JavaScriptFrame* frame) {
 #endif
 
   // Find the call address in the running code.
-  Address addr = frame->pc() - Assembler::kPatchDebugBreakSlotReturnOffset;
+  Address addr = Assembler::break_address_from_return_address(frame->pc());
 
   // Check if the location is at JS return.
   RelocIterator it(debug_info->code());

src/ia32/assembler-ia32-inl.h

@@ -482,6 +482,11 @@ Address Assembler::target_address_from_return_address(Address pc) {
 }
 
 
+Address Assembler::break_address_from_return_address(Address pc) {
+  return pc - Assembler::kPatchDebugBreakSlotReturnOffset;
+}
+
+
 Displacement Assembler::disp_at(Label* L) {
   return Displacement(long_at(L->pos()));
 }

src/ia32/assembler-ia32.h

@@ -519,6 +519,9 @@ class Assembler : public AssemblerBase {
   // of that call in the instruction stream.
   inline static Address target_address_from_return_address(Address pc);
 
+  // Return the code target address of the patch debug break slot
+  inline static Address break_address_from_return_address(Address pc);
+
   // This sets the branch destination (which is in the instruction on x86).
   // This is for calls and branches within generated code.
   inline static void deserialization_set_special_target_at(

src/mips/assembler-mips-inl.h

@@ -190,6 +190,11 @@ Address Assembler::target_address_from_return_address(Address pc) {
 }
 
 
+Address Assembler::break_address_from_return_address(Address pc) {
+  return pc - Assembler::kPatchDebugBreakSlotReturnOffset;
+}
+
+
 Object* RelocInfo::target_object() {
   DCHECK(IsCodeTarget(rmode_) || rmode_ == EMBEDDED_OBJECT);
   return reinterpret_cast<Object*>(Assembler::target_address_at(pc_, host_));

src/mips/assembler-mips.h

@@ -511,6 +511,9 @@ class Assembler : public AssemblerBase {
   // of that call in the instruction stream.
   inline static Address target_address_from_return_address(Address pc);
 
+  // Return the code target address of the patch debug break slot
+  inline static Address break_address_from_return_address(Address pc);
+
   static void JumpLabelToJumpRegister(Address pc);
 
   static void QuietNaN(HeapObject* nan);

src/mips64/assembler-mips64-inl.h

@@ -184,6 +184,11 @@ Address Assembler::target_address_from_return_address(Address pc) {
 }
 
 
+Address Assembler::break_address_from_return_address(Address pc) {
+  return pc - Assembler::kPatchDebugBreakSlotReturnOffset;
+}
+
+
 Object* RelocInfo::target_object() {
   DCHECK(IsCodeTarget(rmode_) || rmode_ == EMBEDDED_OBJECT);
   return reinterpret_cast<Object*>(Assembler::target_address_at(pc_, host_));

src/mips64/assembler-mips64.h

@@ -512,6 +512,9 @@ class Assembler : public AssemblerBase {
   // of that call in the instruction stream.
   inline static Address target_address_from_return_address(Address pc);
 
+  // Return the code target address of the patch debug break slot
+  inline static Address break_address_from_return_address(Address pc);
+
   static void JumpLabelToJumpRegister(Address pc);
 
   static void QuietNaN(HeapObject* nan);

src/x64/assembler-x64-inl.h

@@ -206,6 +206,11 @@ Address Assembler::target_address_from_return_address(Address pc) {
 }
 
 
+Address Assembler::break_address_from_return_address(Address pc) {
+  return pc - Assembler::kPatchDebugBreakSlotReturnOffset;
+}
+
+
 Handle<Object> Assembler::code_target_object_handle_at(Address pc) {
   return code_targets_[Memory::int32_at(pc)];
 }

src/x64/assembler-x64.h

@@ -539,6 +539,9 @@ class Assembler : public AssemblerBase {
   // of that call in the instruction stream.
   static inline Address target_address_from_return_address(Address pc);
 
+  // Return the code target address of the patch debug break slot
+  inline static Address break_address_from_return_address(Address pc);
+
   // This sets the branch destination (which is in the instruction on x64).
   // This is for calls and branches within generated code.
   inline static void deserialization_set_special_target_at(

src/x87/assembler-x87-inl.h

@@ -483,6 +483,11 @@ Address Assembler::target_address_from_return_address(Address pc) {
 }
 
 
+Address Assembler::break_address_from_return_address(Address pc) {
+  return pc - Assembler::kPatchDebugBreakSlotReturnOffset;
+}
+
+
 Displacement Assembler::disp_at(Label* L) {
   return Displacement(long_at(L->pos()));
 }

src/x87/assembler-x87.h

@@ -508,6 +508,9 @@ class Assembler : public AssemblerBase {
   // of that call in the instruction stream.
   inline static Address target_address_from_return_address(Address pc);
 
+  // Return the code target address of the patch debug break slot
+  inline static Address break_address_from_return_address(Address pc);
+
   // This sets the branch destination (which is in the instruction on x86).
   // This is for calls and branches within generated code.
   inline static void deserialization_set_special_target_at(