From 56dc7fc6d3119375950db4275379326db03c060d Mon Sep 17 00:00:00 2001
From: clc5q <clc5q@git.zephyr-software.com>
Date: Thu, 10 Aug 2017 19:21:15 +0000
Subject: [PATCH] Fix constant tracing for func ptrs and handle conditional
move tracing.
Former-commit-id: 8b168e63aac8ff541f7a3e3899be1800087469d4
---
src/base/SMPFunction.cpp | 49 ++++++++++++++++++++++++++++++++++++++--
1 file changed, 47 insertions(+), 2 deletions(-)
diff --git a/src/base/SMPFunction.cpp b/src/base/SMPFunction.cpp
index ba8d70e4..929b2b5e 100644
--- a/src/base/SMPFunction.cpp
+++ b/src/base/SMPFunction.cpp
@@ -13528,7 +13528,52 @@ bool SMPFunction::FindShadowingPoint2(const ShadowPoint CriticalOp, const bool T
break; // cannot follow chain any higher, but previous chain info is still valid.
}
STARSOpndTypePtr NewUseOp = nullptr;
- if (!CurrInst->IsSimpleCopy(NewUseOp)) {
+ // If we have a conditional move instruction, then there will be two USEs. One is the
+ // operand that will be copied to the DEF if the condition is true, and the other is
+ // the operand that represents the unchanged DEF if the copy does not happen, e.g.
+ // if (guard) RDX5 := RAX3; will have USEs RAX3 and RDX4, where RDX4 is the value
+ // that becomes RDX5 when the guard is not true. We need to treat this instruction as
+ // a Phi DEF with two Phi USEs and trace both USEs.
+ if (CurrInst->MDIsConditionalMoveInstr()) {
+ // For each USE other than the flags register, recurse.
+ ShadowSet TempShadowAddrSet; // only union these into ShadowAddrSet if all Phi USE recursions succeed.
+ for (STARSDefUseIter UseIter = CurrInst->GetFirstUse(); UseIter != CurrInst->GetLastUse(); ++UseIter) {
+ int UseSSANum = UseIter->GetSSANum();
+ if (0 > UseSSANum) {
+ SMP_msg("ERROR: FindShadowingPoint2() cannot trace uninitialized CondMove USE at CurrShadowAddr %p in func at %p\n",
+ CurrShadowAddr, this->GetFirstFuncAddr());
+ ValidShadowing = false;
+ break;
+ }
+ STARSOpndTypePtr CondMoveUseOp = UseIter->GetOp()->clone();
+ bool FlagsReg = (CondMoveUseOp->IsRegOp() && (CondMoveUseOp->MatchesReg(MD_FLAGS_REG)));
+ if (!FlagsReg) {
+ this->TempShadowList.SetRef(CondMoveUseOp, UseIter->GetType(), UseSSANum);
+ ShadowPoint UsePoint(CurrShadowAddr, this->TempShadowList.GetSize() - 1);
+ ValidShadowing = this->FindShadowingPoint2(UsePoint, TracingMemWrite, TempShadowAddrSet, MemUnsafe, NewCriticalOps, NonConstSourceFound, ConstValues);
+ if (!ValidShadowing) {
+ break; // we must succeed on all conditional move USEs
+ }
+ }
+ }
+ if (ValidShadowing) { // All USEs succeeded
+ // Remove current CriticalOp from ShadowAddrSet (if present); let the UseOps logically take its place
+ ShadowSet::iterator OldIter = ShadowAddrSet.find(CriticalOp);
+ if (OldIter != ShadowAddrSet.end()) { // found it
+ OldIter = ShadowAddrSet.erase(OldIter);
+ }
+ // Insert the shadow points for all the USEs now that all USE recursions succeeded.
+#if 0
+ ShadowAddrSet.insert(TempShadowAddrSet.begin(), TempShadowAddrSet.end());
+#else
+ for (ShadowSet::const_iterator TempIter = TempShadowAddrSet.cbegin(); TempIter != TempShadowAddrSet.cend(); ++TempIter) {
+ pair<ShadowSet::iterator, bool> InsertResult = ShadowAddrSet.insert(*TempIter);
+ }
+#endif
+ }
+ break; // success if ValidShadowing is true, failure otherwise
+ }
+ else if (!CurrInst->IsSimpleCopy(NewUseOp)) {
NonConstSourceFound = true;
// We could have something like [rsp+32] := [rsp+32] + 8.
// The DEF is the DEF of our CriticalOp, and we cannot trace any farther for this shadowing index.
@@ -13689,7 +13734,7 @@ bool SMPFunction::FindShadowingPoint2(const ShadowPoint CriticalOp, const bool T
}
else {
// Save in the set of constant values we traced back to.
- pair<set<STARS_uval_t>::iterator, bool> InsertResult = ConstValues.insert(ShadowCheckUseOp->GetImmedValue());
+ pair<set<STARS_uval_t>::iterator, bool> InsertResult = ConstValues.insert(NewUseOp->GetImmedValue());
assert(InsertResult.first != ConstValues.end());
}
break;
--
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