Fix uses of MaybeRecordImplicitNullCheck without special scopes

MaybeRecordImplicitNullCheck is a function which uses
CodeGenerator::RecordPcInfo() and requires an exact PC. However for ARM32/ARM64,
when CodeGenerator::RecordPcInfo() is used without VIXL special scopes (EmissionCheckScope,
ExactAssemblyScope) there is no guarantee of an exact PC. Without the special scopes VIXL might
emit veneer/literal pools affecting a PC.
The ARM32 code generator has uses of MaybeRecordImplicitNullCheck without the
special scopes.

This CL fixes missing special scopes in the ARM32/ARM64 code generators.
It also changes API to prevent such cases:
1. A variant of CodeGenerator::RecordPcInfo with native_pc as a
parameter is added. The old variant (where Assembler::CodePosition is used) is
kept and documented that Assembler::CodePosition is target-dependent and
might be imprecise.
2. CodeGenerator::MaybeRecordImplicitNullCheck is made virtual. Checks
are added to ARM32/ARM64 code generators that
MaybeRecordImplicitNullCheck is invoked within VIXL special scopes.

Test: test.py --host --optimizing --jit --gtest
Test: test.py --target --optimizing --jit
Test: run-gtests.sh

Change-Id: Ic66c16e7bdf4751cbc19a9de05846fba005b7f55

1 files changed, 9 insertions, 4 deletions

diff --git a/compiler/optimizing/code_generator.cc b/compiler/optimizing/code_generator.cc
index 6d3a5c6a73..bef7169da1 100644
--- a/compiler/optimizing/code_generator.cc
+++ b/compiler/optimizing/code_generator.cc
@@ -1116,6 +1116,14 @@ void CodeGenerator::RecordPcInfo(HInstruction* instruction,
                                  uint32_t dex_pc,
                                  SlowPathCode* slow_path,
                                  bool native_debug_info) {
+  RecordPcInfo(instruction, dex_pc, GetAssembler()->CodePosition(), slow_path, native_debug_info);
+}
+
+void CodeGenerator::RecordPcInfo(HInstruction* instruction,
+                                 uint32_t dex_pc,
+                                 uint32_t native_pc,
+                                 SlowPathCode* slow_path,
+                                 bool native_debug_info) {
   if (instruction != nullptr) {
     // The code generated for some type conversions
     // may call the runtime, thus normally requiring a subsequent
@@ -1139,9 +1147,6 @@ void CodeGenerator::RecordPcInfo(HInstruction* instruction,
     }
   }
 
-  // Collect PC infos for the mapping table.
-  uint32_t native_pc = GetAssembler()->CodePosition();
-
   StackMapStream* stack_map_stream = GetStackMapStream();
   if (instruction == nullptr) {
     // For stack overflow checks and native-debug-info entries without dex register
@@ -1493,7 +1498,7 @@ bool CodeGenerator::CanMoveNullCheckToUser(HNullCheck* null_check) {
 void CodeGenerator::MaybeRecordImplicitNullCheck(HInstruction* instr) {
   HNullCheck* null_check = instr->GetImplicitNullCheck();
   if (null_check != nullptr) {
-    RecordPcInfo(null_check, null_check->GetDexPc());
+    RecordPcInfo(null_check, null_check->GetDexPc(), GetAssembler()->CodePosition());
   }
 }