[maglev] Fixes LookupExceptionHandlerInTable

Maglev uses a different safepoint table. This CL introduces the
functions FindReturnPCForTrampoline for MaglevFrame and TurboFanFrame.

Bug: v8:7700, chromium:1356902
Change-Id: I90784ddfdc96604c5ada8047e6f7447c17e6c3aa
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3859342
Commit-Queue: Leszek Swirski <leszeks@chromium.org>
Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Auto-Submit: Victor Gomes <victorgomes@chromium.org>
Commit-Queue: Victor Gomes <victorgomes@chromium.org>
Cr-Commit-Position: refs/heads/main@{#82742}

src/codegen/maglev-safepoint-table.cc

@@ -40,6 +40,16 @@ MaglevSafepointTable::MaglevSafepointTable(Address instruction_start,
       num_untagged_slots_(base::Memory<uint32_t>(safepoint_table_address +
                                                  kNumUntaggedSlotsOffset)) {}
 
+int MaglevSafepointTable::find_return_pc(int pc_offset) {
+  for (int i = 0; i < length(); i++) {
+    MaglevSafepointEntry entry = GetEntry(i);
+    if (entry.trampoline_pc() == pc_offset || entry.pc() == pc_offset) {
+      return entry.pc();
+    }
+  }
+  UNREACHABLE();
+}
+
 MaglevSafepointEntry MaglevSafepointTable::FindEntry(Address pc) const {
   int pc_offset = static_cast<int>(pc - instruction_start_);
 

src/codegen/maglev-safepoint-table.h

@@ -74,6 +74,8 @@ class MaglevSafepointTable {
 
   int byte_size() const { return kHeaderSize + length_ * entry_size(); }
 
+  int find_return_pc(int pc_offset);
+
   MaglevSafepointEntry GetEntry(int index) const {
     DCHECK_GT(length_, index);
     Address entry_ptr =

src/execution/frames.cc

@@ -2242,7 +2242,10 @@ int OptimizedFrame::LookupExceptionHandlerInTable(
   // code to perform prediction there.
   DCHECK_NULL(prediction);
   CodeT code = LookupCodeT().ToCodeT();
+
   HandlerTable table(code);
+  if (table.NumberOfReturnEntries() == 0) return -1;
+
   int pc_offset = code.GetOffsetFromInstructionStart(isolate(), pc());
   DCHECK_NULL(data);  // Data is not used and will not return a value.
 
@@ -2250,12 +2253,27 @@ int OptimizedFrame::LookupExceptionHandlerInTable(
   // a handler for this trampoline. Thus we need to use the return pc that
   // _used to be_ on the stack to get the right ExceptionHandler.
   if (CodeKindCanDeoptimize(code.kind()) && code.marked_for_deoptimization()) {
-    SafepointTable safepoints(isolate(), pc(), code);
-    pc_offset = safepoints.find_return_pc(pc_offset);
+    pc_offset = FindReturnPCForTrampoline(code, pc_offset);
   }
   return table.LookupReturn(pc_offset);
 }
 
+int MaglevFrame::FindReturnPCForTrampoline(CodeT code,
+                                           int trampoline_pc) const {
+  DCHECK_EQ(code.kind(), CodeKind::MAGLEV);
+  DCHECK(code.marked_for_deoptimization());
+  MaglevSafepointTable safepoints(isolate(), pc(), code);
+  return safepoints.find_return_pc(trampoline_pc);
+}
+
+int TurbofanFrame::FindReturnPCForTrampoline(CodeT code,
+                                             int trampoline_pc) const {
+  DCHECK_EQ(code.kind(), CodeKind::TURBOFAN);
+  DCHECK(code.marked_for_deoptimization());
+  SafepointTable safepoints(isolate(), pc(), code);
+  return safepoints.find_return_pc(trampoline_pc);
+}
+
 DeoptimizationData OptimizedFrame::GetDeoptimizationData(
     int* deopt_index) const {
   DCHECK(is_optimized());

src/execution/frames.h

@@ -830,6 +830,9 @@ class OptimizedFrame : public JavaScriptFrame {
   int LookupExceptionHandlerInTable(
       int* data, HandlerTable::CatchPrediction* prediction) override;
 
+  virtual int FindReturnPCForTrampoline(CodeT code,
+                                        int trampoline_pc) const = 0;
+
  protected:
   inline explicit OptimizedFrame(StackFrameIteratorBase* iterator);
 };
@@ -939,6 +942,8 @@ class MaglevFrame : public OptimizedFrame {
 
   void Iterate(RootVisitor* v) const override;
 
+  int FindReturnPCForTrampoline(CodeT code, int trampoline_pc) const override;
+
  protected:
   inline explicit MaglevFrame(StackFrameIteratorBase* iterator);
 
@@ -955,6 +960,8 @@ class TurbofanFrame : public OptimizedFrame {
 
   void Iterate(RootVisitor* v) const override;
 
+  int FindReturnPCForTrampoline(CodeT code, int trampoline_pc) const override;
+
  protected:
   inline explicit TurbofanFrame(StackFrameIteratorBase* iterator);