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-rw-r--r--llvm/lib/ProfileData/InstrProf.cpp43
-rw-r--r--llvm/lib/Transforms/Instrumentation/InstrProfiling.cpp16
-rw-r--r--llvm/lib/Transforms/Instrumentation/PGOInstrumentation.cpp28
3 files changed, 71 insertions, 16 deletions
diff --git a/llvm/lib/ProfileData/InstrProf.cpp b/llvm/lib/ProfileData/InstrProf.cpp
index 77c6ffc9c25..74acd9e5e20 100644
--- a/llvm/lib/ProfileData/InstrProf.cpp
+++ b/llvm/lib/ProfileData/InstrProf.cpp
@@ -811,4 +811,47 @@ bool needsComdatForCounter(const Function &F, const Module &M) {
return true;
}
+
+// Check if INSTR_PROF_RAW_VERSION_VAR is defined.
+bool isIRPGOFlagSet(const Module *M) {
+ auto IRInstrVar =
+ M->getNamedGlobal(INSTR_PROF_QUOTE(INSTR_PROF_RAW_VERSION_VAR));
+ if (!IRInstrVar || IRInstrVar->isDeclaration() ||
+ IRInstrVar->hasLocalLinkage())
+ return false;
+
+ // Check if the flag is set.
+ if (!IRInstrVar->hasInitializer())
+ return false;
+
+ const Constant *InitVal = IRInstrVar->getInitializer();
+ if (!InitVal)
+ return false;
+
+ return (dyn_cast<ConstantInt>(InitVal)->getZExtValue() &
+ VARIANT_MASK_IR_PROF) != 0;
+}
+
+// Check if we can safely rename this Comdat function.
+bool canRenameComdatFunc(const Function &F, bool CheckAddressTaken) {
+ if (F.getName().empty())
+ return false;
+ if (!needsComdatForCounter(F, *(F.getParent())))
+ return false;
+ // Unsafe to rename the address-taken function (which can be used in
+ // function comparison).
+ if (CheckAddressTaken && F.hasAddressTaken())
+ return false;
+ // Only safe to do if this function may be discarded if it is not used
+ // in the compilation unit.
+ if (!GlobalValue::isDiscardableIfUnused(F.getLinkage()))
+ return false;
+
+ // For AvailableExternallyLinkage functions.
+ if (!F.hasComdat()) {
+ assert(F.getLinkage() == GlobalValue::AvailableExternallyLinkage);
+ return true;
+ }
+ return true;
+}
} // end namespace llvm
diff --git a/llvm/lib/Transforms/Instrumentation/InstrProfiling.cpp b/llvm/lib/Transforms/Instrumentation/InstrProfiling.cpp
index 8da3e31200f..adea7e77244 100644
--- a/llvm/lib/Transforms/Instrumentation/InstrProfiling.cpp
+++ b/llvm/lib/Transforms/Instrumentation/InstrProfiling.cpp
@@ -32,6 +32,11 @@ cl::opt<bool> DoNameCompression("enable-name-compression",
cl::desc("Enable name string compression"),
cl::init(true));
+cl::opt<bool> DoHashBasedCounterSplit(
+ "hash-based-counter-split",
+ cl::desc("Rename counter variable of a comdat function based on cfg hash"),
+ cl::init(true));
+
cl::opt<bool> ValueProfileStaticAlloc(
"vp-static-alloc",
cl::desc("Do static counter allocation for value profiler"),
@@ -272,7 +277,16 @@ void InstrProfiling::lowerCoverageData(GlobalVariable *CoverageNamesVar) {
static std::string getVarName(InstrProfIncrementInst *Inc, StringRef Prefix) {
StringRef NamePrefix = getInstrProfNameVarPrefix();
StringRef Name = Inc->getName()->getName().substr(NamePrefix.size());
- return (Prefix + Name).str();
+ Function *F = Inc->getParent()->getParent();
+ Module *M = F->getParent();
+ if (!DoHashBasedCounterSplit || !isIRPGOFlagSet(M) ||
+ !canRenameComdatFunc(*F))
+ return (Prefix + Name).str();
+ uint64_t FuncHash = Inc->getHash()->getZExtValue();
+ SmallVector<char, 24> HashPostfix;
+ if (Name.endswith((Twine(".") + Twine(FuncHash)).toStringRef(HashPostfix)))
+ return (Prefix + Name).str();
+ return (Prefix + Name + "." + Twine(FuncHash)).str();
}
static inline bool shouldRecordFunctionAddr(Function *F) {
diff --git a/llvm/lib/Transforms/Instrumentation/PGOInstrumentation.cpp b/llvm/lib/Transforms/Instrumentation/PGOInstrumentation.cpp
index 28f4f7ea145..04f9a64bef9 100644
--- a/llvm/lib/Transforms/Instrumentation/PGOInstrumentation.cpp
+++ b/llvm/lib/Transforms/Instrumentation/PGOInstrumentation.cpp
@@ -119,7 +119,7 @@ static cl::opt<unsigned> MaxNumAnnotations(
// Command line option to control appending FunctionHash to the name of a COMDAT
// function. This is to avoid the hash mismatch caused by the preinliner.
static cl::opt<bool> DoComdatRenaming(
- "do-comdat-renaming", cl::init(true), cl::Hidden,
+ "do-comdat-renaming", cl::init(false), cl::Hidden,
cl::desc("Append function hash to the name of COMDAT function to avoid "
"function hash mismatch due to the preinliner"));
@@ -134,6 +134,12 @@ static cl::opt<bool> PGOWarnMissing("pgo-warn-missing-function",
static cl::opt<bool> NoPGOWarnMismatch("no-pgo-warn-mismatch", cl::init(false),
cl::Hidden);
+// Command line option to enable/disable the warning about a hash mismatch in
+// the profile data for Comdat functions, which often turns out to be false
+// positive due to the pre-instrumentation inline.
+static cl::opt<bool> NoPGOWarnMismatchComdat("no-pgo-warn-mismatch-comdat",
+ cl::init(true), cl::Hidden);
+
// Command line option to enable/disable select instruction instrumentation.
static cl::opt<bool> PGOInstrSelect("pgo-instr-select", cl::init(true),
cl::Hidden);
@@ -407,21 +413,9 @@ void FuncPGOInstrumentation<Edge, BBInfo>::computeCFGHash() {
static bool canRenameComdat(
Function &F,
std::unordered_multimap<Comdat *, GlobalValue *> &ComdatMembers) {
- if (F.getName().empty())
- return false;
- if (!needsComdatForCounter(F, *(F.getParent())))
- return false;
- // Only safe to do if this function may be discarded if it is not used
- // in the compilation unit.
- if (!GlobalValue::isDiscardableIfUnused(F.getLinkage()))
+ if (!DoComdatRenaming || !canRenameComdatFunc(F, true))
return false;
- // For AvailableExternallyLinkage functions.
- if (!F.hasComdat()) {
- assert(F.getLinkage() == GlobalValue::AvailableExternallyLinkage);
- return true;
- }
-
// FIXME: Current only handle those Comdat groups that only containing one
// function and function aliases.
// (1) For a Comdat group containing multiple functions, we need to have a
@@ -803,7 +797,11 @@ bool PGOUseFunc::readCounters(IndexedInstrProfReader *PGOReader) {
} else if (Err == instrprof_error::hash_mismatch ||
Err == instrprof_error::malformed) {
NumOfPGOMismatch++;
- SkipWarning = NoPGOWarnMismatch;
+ SkipWarning =
+ NoPGOWarnMismatch ||
+ (NoPGOWarnMismatchComdat &&
+ (F.hasComdat() ||
+ F.getLinkage() == GlobalValue::AvailableExternallyLinkage));
}
if (SkipWarning)
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