[wasm] Add DebugBreak to debug Liftoff-generated code

DebugBreak allows you to put break points into generated code. When
executed in gdb, the execution will stop in the generated code at the
break point.

R=clemensb@chromium.org

Change-Id: I5607d7ec45d4910412c7adff5ae9bea2c9498909
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2002536
Commit-Queue: Andreas Haas <ahaas@chromium.org>
Reviewed-by: Clemens Backes <clemensb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#65802}

src/wasm/baseline/arm/liftoff-assembler-arm.h

@@ -1658,6 +1658,8 @@ void LiftoffAssembler::DeallocateStackSlot(uint32_t size) {
   add(sp, sp, Operand(size));
 }
 
+void LiftoffAssembler::DebugBreak() { stop(); }
+
 void LiftoffStackSlots::Construct() {
   for (auto& slot : slots_) {
     const LiftoffAssembler::VarState& src = slot.src_;

src/wasm/baseline/arm64/liftoff-assembler-arm64.h

@@ -1143,6 +1143,8 @@ void LiftoffAssembler::DeallocateStackSlot(uint32_t size) {
   Drop(size, 1);
 }
 
+void LiftoffAssembler::DebugBreak() { debug("DebugBreak", 0, BREAK); }
+
 void LiftoffStackSlots::Construct() {
   size_t slot_count = slots_.size();
   // The stack pointer is required to be quadword aligned.

src/wasm/baseline/ia32/liftoff-assembler-ia32.h

@@ -1946,6 +1946,8 @@ void LiftoffAssembler::DeallocateStackSlot(uint32_t size) {
   add(esp, Immediate(size));
 }
 
+void LiftoffAssembler::DebugBreak() { int3(); }
+
 void LiftoffStackSlots::Construct() {
   for (auto& slot : slots_) {
     const LiftoffAssembler::VarState& src = slot.src_;

src/wasm/baseline/liftoff-assembler.h

@@ -689,6 +689,7 @@ class LiftoffAssembler : public TurboAssembler {
   inline void AllocateStackSlot(Register addr, uint32_t size);
   inline void DeallocateStackSlot(uint32_t size);
 
+  inline void DebugBreak();
   ////////////////////////////////////
   // End of platform-specific part. //
   ////////////////////////////////////

src/wasm/baseline/mips/liftoff-assembler-mips.h

@@ -1630,6 +1630,8 @@ void LiftoffAssembler::DeallocateStackSlot(uint32_t size) {
   addiu(sp, sp, size);
 }
 
+void LiftoffAssembler::DebugBreak() { stop(); }
+
 void LiftoffStackSlots::Construct() {
   for (auto& slot : slots_) {
     const LiftoffAssembler::VarState& src = slot.src_;

src/wasm/baseline/mips64/liftoff-assembler-mips64.h

@@ -1422,6 +1422,8 @@ void LiftoffAssembler::DeallocateStackSlot(uint32_t size) {
   daddiu(sp, sp, size);
 }
 
+void LiftoffAssembler::DebugBreak() { stop(); }
+
 void LiftoffStackSlots::Construct() {
   for (auto& slot : slots_) {
     const LiftoffAssembler::VarState& src = slot.src_;

src/wasm/baseline/ppc/liftoff-assembler-ppc.h

@@ -541,6 +541,8 @@ void LiftoffAssembler::DeallocateStackSlot(uint32_t size) {
   bailout(kUnsupportedArchitecture, "DeallocateStackSlot");
 }
 
+void LiftoffAssembler::DebugBreak() { stop(); }
+
 void LiftoffStackSlots::Construct() {
   asm_->bailout(kUnsupportedArchitecture, "LiftoffStackSlots::Construct");
 }

src/wasm/baseline/s390/liftoff-assembler-s390.h

@@ -545,6 +545,8 @@ void LiftoffAssembler::DeallocateStackSlot(uint32_t size) {
   bailout(kUnsupportedArchitecture, "DeallocateStackSlot");
 }
 
+void LiftoffAssembler::DebugBreak() { stop(); }
+
 void LiftoffStackSlots::Construct() {
   asm_->bailout(kUnsupportedArchitecture, "LiftoffStackSlots::Construct");
 }

src/wasm/baseline/x64/liftoff-assembler-x64.h

@@ -1713,6 +1713,8 @@ void LiftoffAssembler::DeallocateStackSlot(uint32_t size) {
   addq(rsp, Immediate(size));
 }
 
+void LiftoffAssembler::DebugBreak() { int3(); }
+
 void LiftoffStackSlots::Construct() {
   for (auto& slot : slots_) {
     const LiftoffAssembler::VarState& src = slot.src_;