Model resource usage for each Thumb/Thumb2 instrution.
This is an mid-point checkin to avoid future merge nightmare for the register
allocator work.
diff --git a/vm/compiler/codegen/arm/LocalOptimizations.c b/vm/compiler/codegen/arm/LocalOptimizations.c
index 6f00b9e..fbc0e26 100644
--- a/vm/compiler/codegen/arm/LocalOptimizations.c
+++ b/vm/compiler/codegen/arm/LocalOptimizations.c
@@ -85,6 +85,11 @@
int nativeRegId = thisLIR->operands[0];
ArmLIR *checkLIR;
int sinkDistance = 0;
+ /*
+ * Add r15 (pc) to the mask to prevent this instruction
+ * from sinking past branch instructions.
+ */
+ u8 stopMask = ENCODE_GP_REG(rpc) | thisLIR->useMask;
for (checkLIR = NEXT_LIR(thisLIR);
checkLIR != tailLIR;
@@ -122,7 +127,7 @@
bool stopHere = false;
/* Last instruction reached */
- stopHere |= checkLIR->generic.next == NULL;
+ stopHere |= NEXT_LIR(checkLIR) == tailLIR;
/*
* Conservatively assume there is a memory dependency
@@ -139,24 +144,12 @@
checkLIR->opCode == THUMB2_VLDRD ||
checkLIR->opCode == THUMB2_VSTRD;
- /* Don't migrate into an IF region */
- stopHere |= checkLIR->opCode == THUMB2_IT;
- if (!isPseudoOpCode(checkLIR->opCode)) {
-
- /* Store data is clobbered */
- stopHere |= (EncodingMap[checkLIR->opCode].flags &
- CLOBBER_DEST) != 0 &&
- regClobber(checkLIR->operands[0],
- nativeRegId);
-
- stopHere |= (EncodingMap[checkLIR->opCode].flags &
- IS_BRANCH) != 0;
- }
+ /* Store data is clobbered */
+ stopHere |= (stopMask & checkLIR->defMask) != 0;
/* Found a new place to put the store - move it here */
if (stopHere == true) {
-
/* The store can be sunk for at least one cycle */
if (sinkDistance != 0) {
ArmLIR *newStoreLIR =
@@ -186,10 +179,126 @@
}
}
+static void applyLoadHoisting(CompilationUnit *cUnit,
+ ArmLIR *headLIR,
+ ArmLIR *tailLIR)
+{
+ ArmLIR *thisLIR;
+
+ cUnit->optRound++;
+ for (thisLIR = headLIR;
+ thisLIR != tailLIR;
+ thisLIR = NEXT_LIR(thisLIR)) {
+ /* Skip newly added instructions */
+ if (thisLIR->age >= cUnit->optRound ||
+ thisLIR->isNop == true) {
+ continue;
+ }
+ if (isDalvikLoad(thisLIR)) {
+ int dRegId = thisLIR->operands[2];
+ int nativeRegId = thisLIR->operands[0];
+ ArmLIR *checkLIR;
+ int hoistDistance = 0;
+ u8 stopUseMask = ENCODE_GP_REG(rpc) | thisLIR->useMask;
+ u8 stopDefMask = thisLIR->defMask;
+
+ for (checkLIR = PREV_LIR(thisLIR);
+ checkLIR != headLIR;
+ checkLIR = PREV_LIR(checkLIR)) {
+
+ if (checkLIR->isNop) continue;
+
+ /* Check if the current load is redundant */
+ if ((isDalvikLoad(checkLIR) || isDalvikStore(checkLIR)) &&
+ checkLIR->operands[2] == dRegId ) {
+ if (FPREG(nativeRegId) != FPREG(checkLIR->operands[0])) {
+ break; // TODO: handle gen<=>float copies
+ }
+ /* Insert a move to replace the load */
+ if (checkLIR->operands[0] != nativeRegId) {
+ ArmLIR *moveLIR;
+ moveLIR = dvmCompilerRegCopy(cUnit,
+ nativeRegId,
+ checkLIR->operands[0]);
+ /*
+ * Convert *thisLIR* load into a move
+ */
+ dvmCompilerInsertLIRAfter((LIR *) checkLIR,
+ (LIR *) moveLIR);
+ }
+ cUnit->printMe = true;
+ thisLIR->isNop = true;
+ break;
+
+ /* Find out if the load can be yanked past the checkLIR */
+ } else {
+ bool stopHere = false;
+
+ /* Last instruction reached */
+ stopHere |= PREV_LIR(checkLIR) == headLIR;
+
+ /*
+ * Conservatively assume there is a memory dependency
+ * for st/ld multiples and reg+reg address mode
+ */
+ stopHere |= checkLIR->opCode == THUMB_STMIA ||
+ checkLIR->opCode == THUMB_LDMIA ||
+ checkLIR->opCode == THUMB_STR_RRR ||
+ checkLIR->opCode == THUMB_LDR_RRR ||
+ checkLIR->opCode == THUMB2_STR_RRR ||
+ checkLIR->opCode == THUMB2_LDR_RRR ||
+ checkLIR->opCode == THUMB2_STMIA ||
+ checkLIR->opCode == THUMB2_LDMIA ||
+ checkLIR->opCode == THUMB2_VLDRD ||
+ checkLIR->opCode == THUMB2_VSTRD;
+
+ /* Base address is clobbered by checkLIR */
+ stopHere |= (stopUseMask & checkLIR->defMask) != 0;
+
+ /* Load target clobbers use/def in checkLIR */
+ stopHere |= (stopDefMask &
+ (checkLIR->useMask | checkLIR->defMask)) != 0;
+
+ /* Found a new place to put the load - move it here */
+ if (stopHere == true) {
+ /* The store can be hoisted for at least one cycle */
+ if (hoistDistance != 0) {
+ ArmLIR *newLoadLIR =
+ dvmCompilerNew(sizeof(ArmLIR), true);
+ *newLoadLIR = *thisLIR;
+ newLoadLIR->age = cUnit->optRound;
+ /*
+ * Insertion is guaranteed to succeed since checkLIR
+ * is never the first LIR on the list
+ */
+ dvmCompilerInsertLIRAfter((LIR *) checkLIR,
+ (LIR *) newLoadLIR);
+ thisLIR->isNop = true;
+ cUnit->printMe = true;
+ }
+ break;
+ }
+
+ /*
+ * Saw a real instruction that the store can be sunk after
+ */
+ if (!isPseudoOpCode(checkLIR->opCode)) {
+ hoistDistance++;
+ }
+ }
+ }
+ }
+ }
+}
+
void dvmCompilerApplyLocalOptimizations(CompilationUnit *cUnit, LIR *headLIR,
LIR *tailLIR)
{
- applyLoadStoreElimination(cUnit,
- (ArmLIR *) headLIR,
- (ArmLIR *) tailLIR);
+ if (!(gDvmJit.disableOpt & (1 << kLoadStoreElimination))) {
+ applyLoadStoreElimination(cUnit, (ArmLIR *) headLIR,
+ (ArmLIR *) tailLIR);
+ }
+ if (!(gDvmJit.disableOpt & (1 << kLoadHoisting))) {
+ applyLoadHoisting(cUnit, (ArmLIR *) headLIR, (ArmLIR *) tailLIR);
+ }
}