[wasm] Add a separate frame type for debug break frames

The frame created by the WasmDebugBreak builtin now has a separate frame
type, which will (later) allow to inspect the spilled registers.

Once Liftoff supports reference types, this frame will also need special
GC support for spilled heap references.

R=jkummerow@chromium.org

Bug: v8:10222
Change-Id: I110e51d1e6d09b0f44dcdd1cdcaafa2eaa64fddd
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2083013Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#66531}

src/builtins/arm/builtins-arm.cc

@@ -2501,8 +2501,7 @@ void Builtins::Generate_WasmCompileLazy(MacroAssembler* masm) {
 void Builtins::Generate_WasmDebugBreak(MacroAssembler* masm) {
   HardAbortScope hard_abort(masm);  // Avoid calls to Abort.
   {
-    // TODO(clemensb): Use a separate frame type and make it inspectable.
-    FrameAndConstantPoolScope scope(masm, StackFrame::INTERNAL);
+    FrameAndConstantPoolScope scope(masm, StackFrame::WASM_DEBUG_BREAK);
 
     // Save all parameter registers. They might hold live values, we restore
     // them after the runtime call.

src/builtins/arm64/builtins-arm64.cc

@@ -3017,8 +3017,7 @@ void Builtins::Generate_WasmCompileLazy(MacroAssembler* masm) {
 void Builtins::Generate_WasmDebugBreak(MacroAssembler* masm) {
   HardAbortScope hard_abort(masm);  // Avoid calls to Abort.
   {
-    // TODO(clemensb): Use a separate frame type and make it inspectable.
-    FrameScope scope(masm, StackFrame::INTERNAL);
+    FrameScope scope(masm, StackFrame::WASM_DEBUG_BREAK);
 
     // Save all parameter registers. They might hold live values, we restore
     // them after the runtime call.

src/builtins/ia32/builtins-ia32.cc

@@ -2672,8 +2672,7 @@ void Builtins::Generate_WasmCompileLazy(MacroAssembler* masm) {
 void Builtins::Generate_WasmDebugBreak(MacroAssembler* masm) {
   HardAbortScope hard_abort(masm);  // Avoid calls to Abort.
   {
-    // TODO(clemensb): Use a separate frame type and make it inspectable.
-    FrameScope scope(masm, StackFrame::INTERNAL);
+    FrameScope scope(masm, StackFrame::WASM_DEBUG_BREAK);
 
     // Save all parameter registers. They might hold live values, we restore
     // them after the runtime call.

src/builtins/mips/builtins-mips.cc

@@ -2484,8 +2484,7 @@ void Builtins::Generate_WasmCompileLazy(MacroAssembler* masm) {
 void Builtins::Generate_WasmDebugBreak(MacroAssembler* masm) {
   HardAbortScope hard_abort(masm);  // Avoid calls to Abort.
   {
-    // TODO(clemensb): Use a separate frame type and make it inspectable.
-    FrameScope scope(masm, StackFrame::INTERNAL);
+    FrameScope scope(masm, StackFrame::WASM_DEBUG_BREAK);
 
     // Save all parameter registers. They might hold live values, we restore
     // them after the runtime call.

src/builtins/mips64/builtins-mips64.cc

@@ -2523,8 +2523,7 @@ void Builtins::Generate_WasmCompileLazy(MacroAssembler* masm) {
 void Builtins::Generate_WasmDebugBreak(MacroAssembler* masm) {
   HardAbortScope hard_abort(masm);  // Avoid calls to Abort.
   {
-    // TODO(clemensb): Use a separate frame type and make it inspectable.
-    FrameScope scope(masm, StackFrame::INTERNAL);
+    FrameScope scope(masm, StackFrame::WASM_DEBUG_BREAK);
 
     // Save all parameter registers. They might hold live values, we restore
     // them after the runtime call.

src/builtins/ppc/builtins-ppc.cc

@@ -2601,8 +2601,7 @@ void Builtins::Generate_WasmCompileLazy(MacroAssembler* masm) {
 void Builtins::Generate_WasmDebugBreak(MacroAssembler* masm) {
   HardAbortScope hard_abort(masm);  // Avoid calls to Abort.
   {
-    // TODO(clemensb): Use a separate frame type and make it inspectable.
-    FrameAndConstantPoolScope scope(masm, StackFrame::INTERNAL);
+    FrameAndConstantPoolScope scope(masm, StackFrame::WASM_DEBUG_BREAK);
 
     // Save all parameter registers. They might hold live values, we restore
     // them after the runtime call.

src/builtins/s390/builtins-s390.cc

@@ -2661,8 +2661,7 @@ void Builtins::Generate_WasmCompileLazy(MacroAssembler* masm) {
 void Builtins::Generate_WasmDebugBreak(MacroAssembler* masm) {
   HardAbortScope hard_abort(masm);  // Avoid calls to Abort.
   {
-    // TODO(clemensb): Use a separate frame type and make it inspectable.
-    FrameAndConstantPoolScope scope(masm, StackFrame::INTERNAL);
+    FrameAndConstantPoolScope scope(masm, StackFrame::WASM_DEBUG_BREAK);
 
     // Save all parameter registers. They might hold live values, we restore
     // them after the runtime call.

src/builtins/x64/builtins-x64.cc

@@ -2643,8 +2643,7 @@ void Builtins::Generate_WasmCompileLazy(MacroAssembler* masm) {
 void Builtins::Generate_WasmDebugBreak(MacroAssembler* masm) {
   HardAbortScope hard_abort(masm);  // Avoid calls to Abort.
   {
-    // TODO(clemensb): Use a separate frame type and make it inspectable.
-    FrameScope scope(masm, StackFrame::INTERNAL);
+    FrameScope scope(masm, StackFrame::WASM_DEBUG_BREAK);
 
     // Save all parameter registers. They might hold live values, we restore
     // them after the runtime call.

src/codegen/arm64/macro-assembler-arm64.cc

@@ -2285,11 +2285,10 @@ void TurboAssembler::Prologue() {
 void TurboAssembler::EnterFrame(StackFrame::Type type) {
   UseScratchRegisterScope temps(this);
 
-  if (type == StackFrame::INTERNAL) {
+  if (type == StackFrame::INTERNAL || type == StackFrame::WASM_DEBUG_BREAK) {
     Register type_reg = temps.AcquireX();
     Mov(type_reg, StackFrame::TypeToMarker(type));
-    // type_reg pushed twice for alignment.
-    Push<TurboAssembler::kSignLR>(lr, fp, type_reg, type_reg);
+    Push<TurboAssembler::kSignLR>(lr, fp, type_reg, padreg);
     const int kFrameSize =
         TypedFrameConstants::kFixedFrameSizeFromFp + kSystemPointerSize;
     Add(fp, sp, kFrameSize);

src/execution/frames-inl.h

@@ -246,6 +246,10 @@ inline WasmInterpreterEntryFrame::WasmInterpreterEntryFrame(
     StackFrameIteratorBase* iterator)
     : StandardFrame(iterator) {}
 
+inline WasmDebugBreakFrame::WasmDebugBreakFrame(
+    StackFrameIteratorBase* iterator)
+    : StandardFrame(iterator) {}
+
 inline WasmToJsFrame::WasmToJsFrame(StackFrameIteratorBase* iterator)
     : StubFrame(iterator) {}
 

src/execution/frames.cc

@@ -622,6 +622,7 @@ StackFrame::Type StackFrame::ComputeType(const StackFrameIteratorBase* iterator,
     case WASM_COMPILED:
     case WASM_COMPILE_LAZY:
     case WASM_EXIT:
+    case WASM_DEBUG_BREAK:
       return candidate;
     case JS_TO_WASM:
     case OPTIMIZED:
@@ -968,6 +969,7 @@ void StandardFrame::IterateCompiledFrame(RootVisitor* v) const {
       case CONSTRUCT:
       case JS_TO_WASM:
       case C_WASM_ENTRY:
+      case WASM_DEBUG_BREAK:
         frame_header_size = TypedFrameConstants::kFixedFrameSizeFromFp;
         break;
       case WASM_TO_JS:
@@ -2031,6 +2033,26 @@ Address WasmInterpreterEntryFrame::GetCallerStackPointer() const {
   return fp() + ExitFrameConstants::kCallerSPOffset;
 }
 
+void WasmDebugBreakFrame::Iterate(RootVisitor* v) const {
+  // Nothing to iterate here. This will change once we support references in
+  // Liftoff.
+}
+
+Code WasmDebugBreakFrame::unchecked_code() const { return Code(); }
+
+void WasmDebugBreakFrame::Print(StringStream* accumulator, PrintMode mode,
+                                int index) const {
+  PrintIndex(accumulator, mode, index);
+  accumulator->Add("WASM DEBUG BREAK");
+  if (mode != OVERVIEW) accumulator->Add("\n");
+}
+
+Address WasmDebugBreakFrame::GetCallerStackPointer() const {
+  // WasmDebugBreak does not receive any arguments, hence the stack pointer of
+  // the caller is at a fixed offset from the frame pointer.
+  return fp() + StandardFrameConstants::kCallerSPOffset;
+}
+
 Code WasmCompileLazyFrame::unchecked_code() const { return Code(); }
 
 WasmInstanceObject WasmCompileLazyFrame::wasm_instance() const {

src/execution/frames.h

@@ -70,6 +70,7 @@ class StackHandler {
   V(WASM_TO_JS, WasmToJsFrame)                                            \
   V(JS_TO_WASM, JsToWasmFrame)                                            \
   V(WASM_INTERPRETER_ENTRY, WasmInterpreterEntryFrame)                    \
+  V(WASM_DEBUG_BREAK, WasmDebugBreakFrame)                                \
   V(C_WASM_ENTRY, CWasmEntryFrame)                                        \
   V(WASM_EXIT, WasmExitFrame)                                             \
   V(WASM_COMPILE_LAZY, WasmCompileLazyFrame)                              \
@@ -181,6 +182,7 @@ class StackFrame {
   bool is_interpreted() const { return type() == INTERPRETED; }
   bool is_wasm_compiled() const { return type() == WASM_COMPILED; }
   bool is_wasm_compile_lazy() const { return type() == WASM_COMPILE_LAZY; }
+  bool is_wasm_debug_break() const { return type() == WASM_DEBUG_BREAK; }
   bool is_wasm_interpreter_entry() const {
     return type() == WASM_INTERPRETER_ENTRY;
   }
@@ -1030,6 +1032,32 @@ class WasmInterpreterEntryFrame final : public StandardFrame {
   WasmModuleObject module_object() const;
 };
 
+class WasmDebugBreakFrame final : public StandardFrame {
+ public:
+  Type type() const override { return WASM_DEBUG_BREAK; }
+
+  // GC support.
+  void Iterate(RootVisitor* v) const override;
+
+  Code unchecked_code() const override;
+
+  void Print(StringStream* accumulator, PrintMode mode,
+             int index) const override;
+
+  static WasmDebugBreakFrame* cast(StackFrame* frame) {
+    DCHECK(frame->is_wasm_debug_break());
+    return static_cast<WasmDebugBreakFrame*>(frame);
+  }
+
+ protected:
+  inline explicit WasmDebugBreakFrame(StackFrameIteratorBase*);
+
+  Address GetCallerStackPointer() const override;
+
+ private:
+  friend class StackFrameIteratorBase;
+};
+
 class WasmToJsFrame : public StubFrame {
  public:
   Type type() const override { return WASM_TO_JS; }

src/runtime/runtime-wasm.cc

@@ -617,7 +617,7 @@ RUNTIME_FUNCTION(Runtime_WasmNewMultiReturnJSArray) {
 RUNTIME_FUNCTION(Runtime_WasmDebugBreak) {
   HandleScope scope(isolate);
   DCHECK_EQ(0, args.length());
-  FrameFinder<WasmCompiledFrame, StackFrame::EXIT, StackFrame::INTERNAL>
+  FrameFinder<WasmCompiledFrame, StackFrame::EXIT, StackFrame::WASM_DEBUG_BREAK>
       frame_finder(isolate);
   auto instance = handle(frame_finder.frame()->wasm_instance(), isolate);
   int position = frame_finder.frame()->position();

tools/v8heapconst.py

@@ -438,6 +438,7 @@ FRAME_MARKERS = (
   "WASM_TO_JS",
   "JS_TO_WASM",
   "WASM_INTERPRETER_ENTRY",
+  "WASM_DEBUG_BREAK",
   "C_WASM_ENTRY",
   "WASM_EXIT",
   "WASM_COMPILE_LAZY",