Fix self-verification with backward branches or invokes.
Bug: 4282508
Change-Id: Iae9d33fd3dc97e88a465fa3128f5108c877470e9
diff --git a/vm/interp/Jit.c b/vm/interp/Jit.c
index c32e922..faf5880 100644
--- a/vm/interp/Jit.c
+++ b/vm/interp/Jit.c
@@ -111,6 +111,7 @@
self->interpSave.fp = (u4*)shadowSpace->shadowFP;
self->interpStackEnd = (u1*)shadowSpace->registerSpace;
+ self->curFrame = self->interpSave.fp;
// Create a copy of the stack
memcpy(((char*)shadowSpace->shadowFP)-preBytes, ((char*)fp)-preBytes,
@@ -156,29 +157,6 @@
// Special case when punting after a single instruction
if (exitState == kSVSPunt && pc == shadowSpace->startPC) {
shadowSpace->selfVerificationState = kSVSIdle;
- } else if (exitState == kSVSBackwardBranch && pc < shadowSpace->startPC) {
- /*
- * Consider a trace with a backward branch:
- * 1: ..
- * 2: ..
- * 3: ..
- * 4: ..
- * 5: Goto {1 or 2 or 3 or 4}
- *
- * If there instruction 5 goes to 1 and there is no single-step
- * instruction in the loop, pc is equal to shadowSpace->startPC and
- * we will honor the backward branch condition.
- *
- * If the single-step instruction is outside the loop, then after
- * resuming in the trace the startPC will be less than pc so we will
- * also honor the backward branch condition.
- *
- * If the single-step is inside the loop, we won't hit the same endPC
- * twice when the interpreter is re-executing the trace so we want to
- * cancel the backward branch condition. In this case it can be
- * detected as the endPC (ie pc) will be less than startPC.
- */
- shadowSpace->selfVerificationState = kSVSNormal;
} else {
shadowSpace->selfVerificationState = exitState;
}
@@ -186,6 +164,7 @@
/* Restore state before returning */
self->interpSave.pc = shadowSpace->startPC;
self->interpSave.fp = shadowSpace->fp;
+ self->curFrame = self->interpSave.fp;
self->interpSave.method = shadowSpace->method;
self->interpSave.methodClassDex = shadowSpace->methodClassDex;
self->retval = shadowSpace->retval;
@@ -303,16 +282,20 @@
}
/*
- * Skip endPC once when trace has a backward branch. If the SV state is
- * single step, keep it that way.
+ * Generalize the self verification state to kSVSDebugInterp unless the
+ * entry reason is kSVSBackwardBranch or kSVSSingleStep.
*/
- if ((state == kSVSBackwardBranch && pc == shadowSpace->endPC) ||
- (state != kSVSBackwardBranch && state != kSVSSingleStep)) {
+ if (state != kSVSBackwardBranch && state != kSVSSingleStep) {
shadowSpace->selfVerificationState = kSVSDebugInterp;
}
- /* Check that the current pc is the end of the trace */
- if ((state == kSVSDebugInterp || state == kSVSSingleStep) &&
+ /*
+ * Check that the current pc is the end of the trace when at least one
+ * instruction is interpreted.
+ */
+ if ((state == kSVSDebugInterp || state == kSVSSingleStep ||
+ state == kSVSBackwardBranch) &&
+ shadowSpace->traceLength != 0 &&
pc == shadowSpace->endPC) {
shadowSpace->selfVerificationState = kSVSIdle;
@@ -322,6 +305,11 @@
shadowSpace->registerSpaceSize*4 -
(int) shadowSpace->shadowFP;
if (memcmp(shadowSpace->fp, shadowSpace->shadowFP, frameBytes)) {
+ if (state == kSVSBackwardBranch) {
+ /* State mismatch on backward branch - try one more iteration */
+ shadowSpace->selfVerificationState = kSVSDebugInterp;
+ goto log_and_continue;
+ }
LOGD("~~~ DbgIntp(%d): REGISTERS DIVERGENCE!", self->threadId);
selfVerificationDumpState(pc, self);
selfVerificationDumpTrace(pc, self);
@@ -346,6 +334,14 @@
(int) self->curFrame - localRegs;
if (memcmp(((char*)self->curFrame)+localRegs,
((char*)shadowSpace->endShadowFP)+localRegs, frameBytes2)) {
+ if (state == kSVSBackwardBranch) {
+ /*
+ * State mismatch on backward branch - try one more
+ * iteration.
+ */
+ shadowSpace->selfVerificationState = kSVSDebugInterp;
+ goto log_and_continue;
+ }
LOGD("~~~ DbgIntp(%d): REGISTERS (FRAME2) DIVERGENCE!",
self->threadId);
selfVerificationDumpState(pc, self);
@@ -371,6 +367,14 @@
heapSpacePtr != shadowSpace->heapSpaceTail; heapSpacePtr++) {
int memData = *((unsigned int*) heapSpacePtr->addr);
if (heapSpacePtr->data != memData) {
+ if (state == kSVSBackwardBranch) {
+ /*
+ * State mismatch on backward branch - try one more
+ * iteration.
+ */
+ shadowSpace->selfVerificationState = kSVSDebugInterp;
+ goto log_and_continue;
+ }
LOGD("~~~ DbgIntp(%d): MEMORY DIVERGENCE!", self->threadId);
LOGD("Addr: 0x%x Intrp Data: 0x%x Jit Data: 0x%x",
heapSpacePtr->addr, memData, heapSpacePtr->data);
@@ -403,16 +407,16 @@
false /* disable */);
self->jitState = kJitDone;
return;
-
+ }
+log_and_continue:
/* If end not been reached, make sure max length not exceeded */
- } else if (shadowSpace->traceLength >= JIT_MAX_TRACE_LEN) {
+ if (shadowSpace->traceLength >= JIT_MAX_TRACE_LEN) {
LOGD("~~~ DbgIntp(%d): CONTROL DIVERGENCE!", self->threadId);
LOGD("startPC: 0x%x endPC: 0x%x currPC: 0x%x",
(int)shadowSpace->startPC, (int)shadowSpace->endPC, (int)pc);
selfVerificationDumpState(pc, self);
selfVerificationDumpTrace(pc, self);
selfVerificationSpinLoop(shadowSpace);
-
return;
}
/* Log the instruction address and decoded instruction for debug */
