Fix exception handling during deoptimization
When interpreting a deoptimized shadow frame, we may start with a
pending exception thrown by a previous deoptimized shadow frame (from
a previous invoke). Therefore, we need to handle it before executing
any instruction, otherwise we execute incorrect code.
Because we need the DEX pc of the throwing instruction to find a
matching catch handler, we initialize deoptimized shadow frames with
the current DEX pc at the time the stack is deoptimized.
When we are about to interpret a deoptimized shadow frame, we need to
update the shadow frame with the DEX pc of the next instruction to
interpret. There are three cases:
- if there is no pending exception, this is the instruction following
the current one.
- if there is a pending exception and we found a matching catch
handler, this is the first instruction of this handler.
- if there is a pending exception but there is no matching catch
handler, we do not execute the deoptimized shadow frame and continue
to its caller.
The verifier now fails when a method starts with a move-exception
instruction. Indeed we cannot start executing a method with a pending
exception.
Bug: 19057915
Bug: 19041195
Bug: 18607595
Change-Id: I355ac81e6ac098edc7e3cc8c13dbfa24a2969ab2
diff --git a/runtime/interpreter/interpreter.cc b/runtime/interpreter/interpreter.cc
index b04a18b..9d988e9 100644
--- a/runtime/interpreter/interpreter.cc
+++ b/runtime/interpreter/interpreter.cc
@@ -493,7 +493,23 @@
while (shadow_frame != NULL) {
self->SetTopOfShadowStack(shadow_frame);
const DexFile::CodeItem* code_item = shadow_frame->GetMethod()->GetCodeItem();
- value = Execute(self, code_item, *shadow_frame, value);
+ const uint32_t dex_pc = shadow_frame->GetDexPC();
+ uint32_t new_dex_pc;
+ if (UNLIKELY(self->IsExceptionPending())) {
+ const instrumentation::Instrumentation* const instrumentation =
+ Runtime::Current()->GetInstrumentation();
+ uint32_t found_dex_pc = FindNextInstructionFollowingException(self, *shadow_frame, dex_pc,
+ instrumentation);
+ new_dex_pc = found_dex_pc; // the dex pc of a matching catch handler
+ // or DexFile::kDexNoIndex if there is none.
+ } else {
+ const Instruction* instr = Instruction::At(&code_item->insns_[dex_pc]);
+ new_dex_pc = dex_pc + instr->SizeInCodeUnits(); // the dex pc of the next instruction.
+ }
+ if (new_dex_pc != DexFile::kDexNoIndex) {
+ shadow_frame->SetDexPC(new_dex_pc);
+ value = Execute(self, code_item, *shadow_frame, value);
+ }
ShadowFrame* old_frame = shadow_frame;
shadow_frame = shadow_frame->GetLink();
delete old_frame;