Fix the bug when -compile-twice is specified, the PSI will be invalidated.

Summary:
When using llc with -compile-twice, module is generated twice, but getAnalysis<ProfileSummaryInfoWrapperPass>().getPSI will still get the old PSI with the original (invalidated) Module. This patch checks if the module has changed when calling getPSI, if yes, update the module and invalidate the Summary.
The bug does not show up in the current llc because PSI is not used in CodeGen yet. But with https://reviews.llvm.org/D24989, the bug will be exposed by test/CodeGen/PowerPC/pr26378.ll

Reviewers: eraman, davidxl

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D24993

llvm-svn: 282616

1 files changed, 12 insertions, 3 deletions

diff --git a/llvm/lib/Analysis/ProfileSummaryInfo.cpp b/llvm/lib/Analysis/ProfileSummaryInfo.cpp
index 300b26552d3..ecfa5c2a3fc 100644
--- a/llvm/lib/Analysis/ProfileSummaryInfo.cpp
+++ b/llvm/lib/Analysis/ProfileSummaryInfo.cpp
@@ -57,7 +57,7 @@ static uint64_t getMinCountForPercentile(SummaryEntryVector &DS,
 void ProfileSummaryInfo::computeSummary() {
   if (Summary)
     return;
-  auto *SummaryMD = M.getProfileSummary();
+  auto *SummaryMD = M->getProfileSummary();
   if (!SummaryMD)
     return;
   Summary.reset(ProfileSummary::getFromMD(SummaryMD));
@@ -113,6 +113,13 @@ void ProfileSummaryInfo::computeThresholds() {
       getMinCountForPercentile(DetailedSummary, ProfileSummaryCutoffCold);
 }
 
+void ProfileSummaryInfo::resetModule(Module *NewM) {
+  if (NewM == M)
+    return;
+  M = NewM;
+  Summary.reset(nullptr);
+}
+
 bool ProfileSummaryInfo::isHotCount(uint64_t C) {
   if (!HotCountThreshold)
     computeThresholds();
@@ -127,7 +134,9 @@ bool ProfileSummaryInfo::isColdCount(uint64_t C) {
 
 ProfileSummaryInfo *ProfileSummaryInfoWrapperPass::getPSI(Module &M) {
   if (!PSI)
-    PSI.reset(new ProfileSummaryInfo(M));
+    PSI.reset(new ProfileSummaryInfo(&M));
+  else
+    PSI->resetModule(&M);
   return PSI.get();
 }
 
@@ -142,7 +151,7 @@ ProfileSummaryInfoWrapperPass::ProfileSummaryInfoWrapperPass()
 char ProfileSummaryAnalysis::PassID;
 ProfileSummaryInfo ProfileSummaryAnalysis::run(Module &M,
                                                ModuleAnalysisManager &) {
-  return ProfileSummaryInfo(M);
+  return ProfileSummaryInfo(&M);
 }
 
 // FIXME: This only tests isHotFunction and isColdFunction and not the