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[MemProf] Merge all callee guids for indirect call VP metadata #170964

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teresajohnson merged 2 commits into from
Dec 8, 2025
Merged

[MemProf] Merge all callee guids for indirect call VP metadata #170964

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2d8716d
[MemProf] Merge all callee guids for indirect call VP metadata
teresajohnson Dec 6, 2025
ebbdf03
Try to resolve Windows pre-commit failure. The CallSiteEntries were
teresajohnson Dec 8, 2025
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83 changes: 41 additions & 42 deletions llvm/lib/Transforms/Instrumentation/MemProfUse.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -504,59 +504,59 @@ struct CallSiteEntry {
ArrayRef<Frame> Frames;
// Potential targets for indirect calls.
ArrayRef<GlobalValue::GUID> CalleeGuids;

// Only compare Frame contents.
// Use pointer-based equality instead of ArrayRef's operator== which does
// element-wise comparison. We want to check if it's the same slice of the
// underlying array, not just equivalent content.
bool operator==(const CallSiteEntry &Other) const {
return Frames.data() == Other.Frames.data() &&
Frames.size() == Other.Frames.size();
}
};

struct CallSiteEntryHash {
size_t operator()(const CallSiteEntry &Entry) const {
return computeFullStackId(Entry.Frames);
}
};

static void handleCallSite(
Instruction &I, const Function *CalledFunction,
ArrayRef<uint64_t> InlinedCallStack,
const std::unordered_set<CallSiteEntry, CallSiteEntryHash> &CallSiteEntries,
Module &M, std::set<std::vector<uint64_t>> &MatchedCallSites,
OptimizationRemarkEmitter &ORE) {
static void handleCallSite(Instruction &I, const Function *CalledFunction,
ArrayRef<uint64_t> InlinedCallStack,
const std::vector<CallSiteEntry> &CallSiteEntries,
Module &M,
std::set<std::vector<uint64_t>> &MatchedCallSites,
OptimizationRemarkEmitter &ORE) {
auto &Ctx = M.getContext();
// Set of Callee GUIDs to attach to indirect calls. We accumulate all of them
// to support cases where the instuction's inlined frames match multiple call
// site entries, which can happen if the profile was collected from a binary
// where this instruction was eventually inlined into multiple callers.
SetVector<GlobalValue::GUID> CalleeGuids;
bool CallsiteMDAdded = false;
for (const auto &CallSiteEntry : CallSiteEntries) {
// If we found and thus matched all frames on the call, create and
// attach call stack metadata.
if (stackFrameIncludesInlinedCallStack(CallSiteEntry.Frames,
InlinedCallStack)) {
NumOfMemProfMatchedCallSites++;
addCallsiteMetadata(I, InlinedCallStack, Ctx);

// Try to attach indirect call metadata if possible.
if (!CalledFunction)
addVPMetadata(M, I, CallSiteEntry.CalleeGuids);

// Only need to find one with a matching call stack and add a single
// callsite metadata.

// Accumulate call site matching information upon request.
if (ClPrintMemProfMatchInfo) {
std::vector<uint64_t> CallStack;
append_range(CallStack, InlinedCallStack);
MatchedCallSites.insert(std::move(CallStack));
if (!CallsiteMDAdded) {
addCallsiteMetadata(I, InlinedCallStack, Ctx);

// Accumulate call site matching information upon request.
if (ClPrintMemProfMatchInfo) {
std::vector<uint64_t> CallStack;
append_range(CallStack, InlinedCallStack);
MatchedCallSites.insert(std::move(CallStack));
}
ORE.emit(OptimizationRemark(DEBUG_TYPE, "MemProfUse", &I)
<< ore::NV("CallSite", &I) << " in function "
<< ore::NV("Caller", I.getFunction())
<< " matched callsite with frame count "
<< ore::NV("Frames", InlinedCallStack.size()));

// If this is a direct call, we're done.
if (CalledFunction)
break;
CallsiteMDAdded = true;
}
ORE.emit(OptimizationRemark(DEBUG_TYPE, "MemProfUse", &I)
<< ore::NV("CallSite", &I) << " in function "
<< ore::NV("Caller", I.getFunction())
<< " matched callsite with frame count "
<< ore::NV("Frames", InlinedCallStack.size()));
break;

assert(!CalledFunction && "Didn't expect direct call");

// Collect Callee GUIDs from all matching CallSiteEntries.
CalleeGuids.insert(CallSiteEntry.CalleeGuids.begin(),
CallSiteEntry.CalleeGuids.end());
}
}
// Try to attach indirect call metadata if possible.
addVPMetadata(M, I, CalleeGuids.getArrayRef());
}

static void readMemprof(Module &M, Function &F,
Expand Down Expand Up @@ -631,8 +631,7 @@ static void readMemprof(Module &M, Function &F,

// For the callsites we need to record slices of the frame array (see comments
// below where the map entries are added) along with their CalleeGuids.
std::map<uint64_t, std::unordered_set<CallSiteEntry, CallSiteEntryHash>>
LocHashToCallSites;
std::map<uint64_t, std::vector<CallSiteEntry>> LocHashToCallSites;
for (auto &AI : MemProfRec->AllocSites) {
NumOfMemProfAllocContextProfiles++;
// Associate the allocation info with the leaf frame. The later matching
Expand All @@ -651,7 +650,7 @@ static void readMemprof(Module &M, Function &F,
uint64_t StackId = computeStackId(StackFrame);
ArrayRef<Frame> FrameSlice = ArrayRef<Frame>(CS.Frames).drop_front(Idx++);
ArrayRef<GlobalValue::GUID> CalleeGuids(CS.CalleeGuids);
LocHashToCallSites[StackId].insert({FrameSlice, CalleeGuids});
LocHashToCallSites[StackId].push_back({FrameSlice, CalleeGuids});

ProfileHasColumns |= StackFrame.Column;
// Once we find this function, we can stop recording.
Expand Down
16 changes: 14 additions & 2 deletions llvm/test/Transforms/PGOProfile/memprof_annotate_indirect_call.test
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Original file line number Diff line number Diff line change
Expand Up @@ -3,7 +3,7 @@
;; Basic functionality with flag toggle
; RUN: llvm-profdata merge --memprof-version=4 %t/basic.yaml -o %t/basic.memprofdata
; RUN: opt < %t/basic.ll -passes='memprof-use<profile-filename=%t/basic.memprofdata>' -memprof-attach-calleeguids=false -S 2>&1 | FileCheck %s --check-prefix=CHECK-DISABLE
; RUN: opt < %t/basic.ll -passes='memprof-use<profile-filename=%t/basic.memprofdata>' -memprof-attach-calleeguids=true -S 2>&1 | FileCheck %s --check-prefix=CHECK-ENABLE
; RUN: opt < %t/basic.ll -passes='memprof-use<profile-filename=%t/basic.memprofdata>' -memprof-attach-calleeguids=true -S 2>&1 | FileCheck %s --check-prefix=CHECK-ENABLE --dump-input-filter=all

;; FDO conflict handling
; RUN: llvm-profdata merge --memprof-version=4 %t/fdo_conflict.yaml -o %t/fdo_conflict.memprofdata
Expand All @@ -18,6 +18,18 @@ HeapProfileRecords:
- Frames:
- { Function: _Z3barv, LineOffset: 3, Column: 5, IsInlineFrame: false }
CalleeGuids: [0x123456789abcdef0, 0x23456789abcdef01]
# The next 2 sets of frames simulates the case where this function was
# eventually inlined into multiple callers. We would have propagated the
# resulting frames and callee guids here for matching with they not yet
# inlined bar. We should aggregate all callee guids into the metadata.
- Frames:
- { Function: _Z3barv, LineOffset: 3, Column: 5, IsInlineFrame: true }
- { Function: _Z3foov, LineOffset: 1, Column: 6, IsInlineFrame: false }
CalleeGuids: [0x1234, 0x2345]
- Frames:
- { Function: _Z3barv, LineOffset: 3, Column: 5, IsInlineFrame: true }
- { Function: _Z3foov, LineOffset: 10, Column: 7, IsInlineFrame: false }
CalleeGuids: [0x3456, 0x4567]
...

;--- basic.ll
Expand All @@ -31,7 +43,7 @@ entry:
ret void
}

; CHECK-ENABLE: !6 = !{!"VP", i32 0, i64 2, i64 1311768467463790320, i64 1, i64 2541551405711093505, i64 1}
; CHECK-ENABLE: !6 = !{!"VP", i32 0, i64 6, i64 1311768467463790320, i64 1, i64 2541551405711093505, i64 1, i64 4660, i64 1, i64 9029, i64 1, i64 13398, i64 1, i64 17767, i64 1}

!llvm.module.flags = !{!2, !3}

Expand Down
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