Generate Nops to ensure that debug stack maps have distinct PC.

Change-Id: I5740ec958a20d236634b66df0e675382ed5c16fc

8 files changed, 32 insertions, 0 deletions

diff --git a/compiler/optimizing/code_generator.cc b/compiler/optimizing/code_generator.cc
index 53d3615a41..57c5058cfb 100644
--- a/compiler/optimizing/code_generator.cc
+++ b/compiler/optimizing/code_generator.cc
@@ -997,6 +997,12 @@ void CodeGenerator::RecordPcInfo(HInstruction* instruction,
   stack_map_stream_.EndStackMapEntry();
 }
 
+bool CodeGenerator::HasStackMapAtCurrentPc() {
+  uint32_t pc = GetAssembler()->CodeSize();
+  size_t count = stack_map_stream_.GetNumberOfStackMaps();
+  return count > 0 && stack_map_stream_.GetStackMap(count - 1).native_pc_offset == pc;
+}
+
 void CodeGenerator::RecordCatchBlockInfo() {
   ArenaAllocator* arena = graph_->GetArena();
 
diff --git a/compiler/optimizing/code_generator.h b/compiler/optimizing/code_generator.h
index eade05d7b6..950043ea71 100644
--- a/compiler/optimizing/code_generator.h
+++ b/compiler/optimizing/code_generator.h
@@ -269,6 +269,8 @@ class CodeGenerator {
 
   // Record native to dex mapping for a suspend point.  Required by runtime.
   void RecordPcInfo(HInstruction* instruction, uint32_t dex_pc, SlowPathCode* slow_path = nullptr);
+  // Check whether we have already recorded mapping at this PC.
+  bool HasStackMapAtCurrentPc();
 
   bool CanMoveNullCheckToUser(HNullCheck* null_check);
   void MaybeRecordImplicitNullCheck(HInstruction* instruction);
diff --git a/compiler/optimizing/code_generator_arm.cc b/compiler/optimizing/code_generator_arm.cc
index b32a81a2e4..7b167e48f4 100644
--- a/compiler/optimizing/code_generator_arm.cc
+++ b/compiler/optimizing/code_generator_arm.cc
@@ -1679,6 +1679,10 @@ void LocationsBuilderARM::VisitNativeDebugInfo(HNativeDebugInfo* info) {
 }
 
 void InstructionCodeGeneratorARM::VisitNativeDebugInfo(HNativeDebugInfo* info) {
+  if (codegen_->HasStackMapAtCurrentPc()) {
+    // Ensure that we do not collide with the stack map of the previous instruction.
+    __ nop();
+  }
   codegen_->RecordPcInfo(info, info->GetDexPc());
 }
 
diff --git a/compiler/optimizing/code_generator_arm64.cc b/compiler/optimizing/code_generator_arm64.cc
index b49f42b6c8..b3d0945991 100644
--- a/compiler/optimizing/code_generator_arm64.cc
+++ b/compiler/optimizing/code_generator_arm64.cc
@@ -2954,6 +2954,10 @@ void LocationsBuilderARM64::VisitNativeDebugInfo(HNativeDebugInfo* info) {
 }
 
 void InstructionCodeGeneratorARM64::VisitNativeDebugInfo(HNativeDebugInfo* info) {
+  if (codegen_->HasStackMapAtCurrentPc()) {
+    // Ensure that we do not collide with the stack map of the previous instruction.
+    __ Nop();
+  }
   codegen_->RecordPcInfo(info, info->GetDexPc());
 }
 
diff --git a/compiler/optimizing/code_generator_mips.cc b/compiler/optimizing/code_generator_mips.cc
index 4648606da8..ee14c6d140 100644
--- a/compiler/optimizing/code_generator_mips.cc
+++ b/compiler/optimizing/code_generator_mips.cc
@@ -3371,6 +3371,10 @@ void LocationsBuilderMIPS::VisitNativeDebugInfo(HNativeDebugInfo* info) {
 }
 
 void InstructionCodeGeneratorMIPS::VisitNativeDebugInfo(HNativeDebugInfo* info) {
+  if (codegen_->HasStackMapAtCurrentPc()) {
+    // Ensure that we do not collide with the stack map of the previous instruction.
+    __ Nop();
+  }
   codegen_->RecordPcInfo(info, info->GetDexPc());
 }
 
diff --git a/compiler/optimizing/code_generator_mips64.cc b/compiler/optimizing/code_generator_mips64.cc
index 05834ff063..e334100e1c 100644
--- a/compiler/optimizing/code_generator_mips64.cc
+++ b/compiler/optimizing/code_generator_mips64.cc
@@ -2750,6 +2750,10 @@ void LocationsBuilderMIPS64::VisitNativeDebugInfo(HNativeDebugInfo* info) {
 }
 
 void InstructionCodeGeneratorMIPS64::VisitNativeDebugInfo(HNativeDebugInfo* info) {
+  if (codegen_->HasStackMapAtCurrentPc()) {
+    // Ensure that we do not collide with the stack map of the previous instruction.
+    __ Nop();
+  }
   codegen_->RecordPcInfo(info, info->GetDexPc());
 }
 
diff --git a/compiler/optimizing/code_generator_x86.cc b/compiler/optimizing/code_generator_x86.cc
index a808c27313..8910249f20 100644
--- a/compiler/optimizing/code_generator_x86.cc
+++ b/compiler/optimizing/code_generator_x86.cc
@@ -1625,6 +1625,10 @@ void LocationsBuilderX86::VisitNativeDebugInfo(HNativeDebugInfo* info) {
 }
 
 void InstructionCodeGeneratorX86::VisitNativeDebugInfo(HNativeDebugInfo* info) {
+  if (codegen_->HasStackMapAtCurrentPc()) {
+    // Ensure that we do not collide with the stack map of the previous instruction.
+    __ nop();
+  }
   codegen_->RecordPcInfo(info, info->GetDexPc());
 }
 
diff --git a/compiler/optimizing/code_generator_x86_64.cc b/compiler/optimizing/code_generator_x86_64.cc
index 76a4ce2e93..126c83b17e 100644
--- a/compiler/optimizing/code_generator_x86_64.cc
+++ b/compiler/optimizing/code_generator_x86_64.cc
@@ -1608,6 +1608,10 @@ void LocationsBuilderX86_64::VisitNativeDebugInfo(HNativeDebugInfo* info) {
 }
 
 void InstructionCodeGeneratorX86_64::VisitNativeDebugInfo(HNativeDebugInfo* info) {
+  if (codegen_->HasStackMapAtCurrentPc()) {
+    // Ensure that we do not collide with the stack map of the previous instruction.
+    __ nop();
+  }
   codegen_->RecordPcInfo(info, info->GetDexPc());
 }