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May 9, 2025
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[MemProf] Disable alloc context in combined summary for ndebug builds #139161

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[MemProf] Disable alloc context in combined summary for ndebug builds
teresajohnson May 8, 2025
572e558
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teresajohnson May 9, 2025
d0c3b86
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teresajohnson May 9, 2025
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5 changes: 5 additions & 0 deletions llvm/include/llvm/Bitcode/LLVMBitCodes.h
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Expand Up @@ -335,6 +335,11 @@ enum GlobalValueSummarySymtabCodes {
// CallStackRadixTreeBuilder class in ProfileData/MemProf.h for format.
// [n x entry]
FS_CONTEXT_RADIX_TREE_ARRAY = 32,
// Summary of combined index allocation memprof metadata, without context.
// [nummib, numver,
// nummib x alloc type,
// numver x version]
FS_COMBINED_ALLOC_INFO_NO_CONTEXT = 33,
};

enum MetadataCodes {
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15 changes: 9 additions & 6 deletions llvm/lib/AsmParser/LLParser.cpp
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Expand Up @@ -10781,12 +10781,15 @@ bool LLParser::parseMemProfs(std::vector<MIBInfo> &MIBs) {
return true;

SmallVector<unsigned> StackIdIndices;
do {
uint64_t StackId = 0;
if (parseUInt64(StackId))
return true;
StackIdIndices.push_back(Index->addOrGetStackIdIndex(StackId));
} while (EatIfPresent(lltok::comma));
// Combined index alloc records may not have a stack id list.
if (Lex.getKind() != lltok::rparen) {
do {
uint64_t StackId = 0;
if (parseUInt64(StackId))
return true;
StackIdIndices.push_back(Index->addOrGetStackIdIndex(StackId));
} while (EatIfPresent(lltok::comma));
}

if (parseToken(lltok::rparen, "expected ')' in stackIds"))
return true;
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1 change: 1 addition & 0 deletions llvm/lib/Bitcode/Reader/BitcodeAnalyzer.cpp
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Expand Up @@ -330,6 +330,7 @@ GetCodeName(unsigned CodeID, unsigned BlockID,
STRINGIFY_CODE(FS, STACK_IDS)
STRINGIFY_CODE(FS, ALLOC_CONTEXT_IDS)
STRINGIFY_CODE(FS, CONTEXT_RADIX_TREE_ARRAY)
STRINGIFY_CODE(FS, COMBINED_ALLOC_INFO_NO_CONTEXT)
}
case bitc::METADATA_ATTACHMENT_ID:
switch (CodeID) {
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7 changes: 5 additions & 2 deletions llvm/lib/Bitcode/Reader/BitcodeReader.cpp
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Expand Up @@ -8178,7 +8178,8 @@ Error ModuleSummaryIndexBitcodeReader::parseEntireSummary(unsigned ID) {
break;
}

case bitc::FS_COMBINED_ALLOC_INFO: {
case bitc::FS_COMBINED_ALLOC_INFO:
case bitc::FS_COMBINED_ALLOC_INFO_NO_CONTEXT: {
unsigned I = 0;
std::vector<MIBInfo> MIBs;
unsigned NumMIBs = Record[I++];
Expand All @@ -8187,7 +8188,9 @@ Error ModuleSummaryIndexBitcodeReader::parseEntireSummary(unsigned ID) {
while (MIBsRead++ < NumMIBs) {
assert(Record.size() - I >= 2);
AllocationType AllocType = (AllocationType)Record[I++];
auto StackIdList = parseAllocInfoContext(Record, I);
SmallVector<unsigned> StackIdList;
if (BitCode == bitc::FS_COMBINED_ALLOC_INFO)
StackIdList = parseAllocInfoContext(Record, I);
MIBs.push_back(MIBInfo(AllocType, std::move(StackIdList)));
}
assert(Record.size() - I >= NumVersions);
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135 changes: 83 additions & 52 deletions llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
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Expand Up @@ -99,6 +99,22 @@ static cl::opt<bool> WriteRelBFToSummary(
"write-relbf-to-summary", cl::Hidden, cl::init(false),
cl::desc("Write relative block frequency to function summary "));

// Since we only use the context information in the memprof summary records in
// the LTO backends to do assertion checking, save time and space by only
// serializing the context for non-NDEBUG builds.
// TODO: Currently this controls writing context of the allocation info records,
// which are larger and more expensive, but we should do this for the callsite
// records as well.
// FIXME: Convert to a const once this has undergone more sigificant testing.
static cl::opt<bool>
CombinedIndexMemProfContext("combined-index-memprof-context", cl::Hidden,
#ifdef NDEBUG
cl::init(false),
#else
cl::init(true),
#endif
cl::desc(""));

namespace llvm {
extern FunctionSummary::ForceSummaryHotnessType ForceSummaryEdgesCold;
}
Expand Down Expand Up @@ -528,10 +544,12 @@ class IndexBitcodeWriter : public BitcodeWriterBase {
for (auto Idx : CI.StackIdIndices)
RecordStackIdReference(Idx);
}
for (auto &AI : FS->allocs())
for (auto &MIB : AI.MIBs)
for (auto Idx : MIB.StackIdIndices)
RecordStackIdReference(Idx);
if (CombinedIndexMemProfContext) {
for (auto &AI : FS->allocs())
for (auto &MIB : AI.MIBs)
for (auto Idx : MIB.StackIdIndices)
RecordStackIdReference(Idx);
}
});
}

Expand Down Expand Up @@ -4349,9 +4367,14 @@ static void writeFunctionHeapProfileRecords(
Record.push_back(AI.Versions.size());
for (auto &MIB : AI.MIBs) {
Record.push_back((uint8_t)MIB.AllocType);
// Record the index into the radix tree array for this context.
assert(CallStackCount <= CallStackPos.size());
Record.push_back(CallStackPos[CallStackCount++]);
// The per-module summary always needs to include the alloc context, as we
// use it during the thin link. For the combined index it is optional (see
// comments where CombinedIndexMemProfContext is defined).
if (PerModule || CombinedIndexMemProfContext) {
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Can you explain a bit about the PerModule usage here and below?

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Added a comment here. The below usage was pre-existing so I wasn't sure another comment was needed.

// Record the index into the radix tree array for this context.
assert(CallStackCount <= CallStackPos.size());
Record.push_back(CallStackPos[CallStackCount++]);
}
}
if (!PerModule)
llvm::append_range(Record, AI.Versions);
Expand Down Expand Up @@ -4384,8 +4407,11 @@ static void writeFunctionHeapProfileRecords(
Stream.EmitRecord(bitc::FS_ALLOC_CONTEXT_IDS, ContextIds,
ContextIdAbbvId);
}
Stream.EmitRecord(PerModule ? bitc::FS_PERMODULE_ALLOC_INFO
: bitc::FS_COMBINED_ALLOC_INFO,
Stream.EmitRecord(PerModule
? bitc::FS_PERMODULE_ALLOC_INFO
: (CombinedIndexMemProfContext
? bitc::FS_COMBINED_ALLOC_INFO
: bitc::FS_COMBINED_ALLOC_INFO_NO_CONTEXT),
Record, AllocAbbrev);
}
}
Expand Down Expand Up @@ -4847,7 +4873,9 @@ void IndexBitcodeWriter::writeCombinedGlobalValueSummary() {
unsigned CallsiteAbbrev = Stream.EmitAbbrev(std::move(Abbv));

Abbv = std::make_shared<BitCodeAbbrev>();
Abbv->Add(BitCodeAbbrevOp(bitc::FS_COMBINED_ALLOC_INFO));
Abbv->Add(BitCodeAbbrevOp(CombinedIndexMemProfContext
? bitc::FS_COMBINED_ALLOC_INFO
: bitc::FS_COMBINED_ALLOC_INFO_NO_CONTEXT));
Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // nummib
Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 4)); // numver
// nummib x (alloc type, context radix tree index),
Expand All @@ -4857,13 +4885,6 @@ void IndexBitcodeWriter::writeCombinedGlobalValueSummary() {
Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
unsigned AllocAbbrev = Stream.EmitAbbrev(std::move(Abbv));

Abbv = std::make_shared<BitCodeAbbrev>();
Abbv->Add(BitCodeAbbrevOp(bitc::FS_CONTEXT_RADIX_TREE_ARRAY));
// n x entry
Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
unsigned RadixAbbrev = Stream.EmitAbbrev(std::move(Abbv));

auto shouldImportValueAsDecl = [&](GlobalValueSummary *GVS) -> bool {
if (DecSummaries == nullptr)
return false;
Expand Down Expand Up @@ -4900,44 +4921,54 @@ void IndexBitcodeWriter::writeCombinedGlobalValueSummary() {
NameVals.clear();
};

// First walk through all the functions and collect the allocation contexts in
// their associated summaries, for use in constructing a radix tree of
// contexts. Note that we need to do this in the same order as the functions
// are processed further below since the call stack positions in the resulting
// radix tree array are identified based on this order.
MapVector<CallStackId, llvm::SmallVector<LinearFrameId>> CallStacks;
forEachSummary([&](GVInfo I, bool IsAliasee) {
// Don't collect this when invoked for an aliasee, as it is not needed for
// the alias summary. If the aliasee is to be imported, we will invoke this
// separately with IsAliasee=false.
if (IsAliasee)
return;
GlobalValueSummary *S = I.second;
assert(S);
auto *FS = dyn_cast<FunctionSummary>(S);
if (!FS)
return;
collectMemProfCallStacks(
FS,
/*GetStackIndex*/
[&](unsigned I) {
// Get the corresponding index into the list of StackIds actually
// being written for this combined index (which may be a subset in
// the case of distributed indexes).
assert(StackIdIndicesToIndex.contains(I));
return StackIdIndicesToIndex[I];
},
CallStacks);
});
// Finalize the radix tree, write it out, and get the map of positions in the
// linearized tree array.
DenseMap<CallStackId, LinearCallStackId> CallStackPos;
if (!CallStacks.empty()) {
CallStackPos =
writeMemoryProfileRadixTree(std::move(CallStacks), Stream, RadixAbbrev);
if (CombinedIndexMemProfContext) {
Abbv = std::make_shared<BitCodeAbbrev>();
Abbv->Add(BitCodeAbbrevOp(bitc::FS_CONTEXT_RADIX_TREE_ARRAY));
// n x entry
Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::Array));
Abbv->Add(BitCodeAbbrevOp(BitCodeAbbrevOp::VBR, 8));
unsigned RadixAbbrev = Stream.EmitAbbrev(std::move(Abbv));

// First walk through all the functions and collect the allocation contexts
// in their associated summaries, for use in constructing a radix tree of
// contexts. Note that we need to do this in the same order as the functions
// are processed further below since the call stack positions in the
// resulting radix tree array are identified based on this order.
MapVector<CallStackId, llvm::SmallVector<LinearFrameId>> CallStacks;
forEachSummary([&](GVInfo I, bool IsAliasee) {
// Don't collect this when invoked for an aliasee, as it is not needed for
// the alias summary. If the aliasee is to be imported, we will invoke
// this separately with IsAliasee=false.
if (IsAliasee)
return;
GlobalValueSummary *S = I.second;
assert(S);
auto *FS = dyn_cast<FunctionSummary>(S);
if (!FS)
return;
collectMemProfCallStacks(
FS,
/*GetStackIndex*/
[&](unsigned I) {
// Get the corresponding index into the list of StackIds actually
// being written for this combined index (which may be a subset in
// the case of distributed indexes).
assert(StackIdIndicesToIndex.contains(I));
return StackIdIndicesToIndex[I];
},
CallStacks);
});
// Finalize the radix tree, write it out, and get the map of positions in
// the linearized tree array.
if (!CallStacks.empty()) {
CallStackPos = writeMemoryProfileRadixTree(std::move(CallStacks), Stream,
RadixAbbrev);
}
}

// Keep track of the current index into the CallStackPos map.
// Keep track of the current index into the CallStackPos map. Not used if
// CombinedIndexMemProfContext is false.
CallStackId CallStackCount = 0;

DenseSet<GlobalValue::GUID> DefOrUseGUIDs;
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15 changes: 12 additions & 3 deletions llvm/test/Assembler/thinlto-memprof-summary.ll
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@@ -1,5 +1,12 @@
;; Test memprof summary parsing (tests all types/fields in various combinations).
; RUN: llvm-as %s -o - | llvm-dis -o - | FileCheck %s

;; Force enable -combined-index-memprof-context to get the allocation context
;; stack ids even in release builds.
; RUN: llvm-as %s -o - -combined-index-memprof-context | llvm-dis -o - | FileCheck %s --check-prefixes=CHECK,CONTEXT

;; Force disable -combined-index-memprof-context to block the allocation context
;; stack ids even in non-release builds.
; RUN: llvm-as %s -o - -combined-index-memprof-context=false | llvm-dis -o - | FileCheck %s --check-prefixes=CHECK,NOCONTEXT

; ModuleID = 'thinlto-memprof-summary.thinlto.bc'

Expand All @@ -17,8 +24,10 @@

; Make sure we get back from llvm-dis what we put in via llvm-as.
; CHECK: ^0 = module: (path: "thinlto-memprof-summary.o", hash: (1369602428, 2747878711, 259090915, 2507395659, 1141468049))
; CHECK: ^1 = gv: (guid: 23, summaries: (function: (module: ^0, flags: (linkage: external, visibility: default, notEligibleToImport: 0, live: 0, dsoLocal: 1, canAutoHide: 0, importType: definition), insts: 2, funcFlags: (readNone: 0, readOnly: 0, noRecurse: 0, returnDoesNotAlias: 0, noInline: 1, alwaysInline: 0, noUnwind: 0, mayThrow: 0, hasUnknownCall: 0, mustBeUnreachable: 0), allocs: ((versions: (none), memProf: ((type: notcold, stackIds: (8632435727821051414)), (type: cold, stackIds: (15025054523792398438, 12345678)), (type: hot, stackIds: (987654321))))))))
; CONTEXT: ^1 = gv: (guid: 23, summaries: (function: (module: ^0, flags: (linkage: external, visibility: default, notEligibleToImport: 0, live: 0, dsoLocal: 1, canAutoHide: 0, importType: definition), insts: 2, funcFlags: (readNone: 0, readOnly: 0, noRecurse: 0, returnDoesNotAlias: 0, noInline: 1, alwaysInline: 0, noUnwind: 0, mayThrow: 0, hasUnknownCall: 0, mustBeUnreachable: 0), allocs: ((versions: (none), memProf: ((type: notcold, stackIds: (8632435727821051414)), (type: cold, stackIds: (15025054523792398438, 12345678)), (type: hot, stackIds: (987654321))))))))
; NOCONTEXT: ^1 = gv: (guid: 23, summaries: (function: (module: ^0, flags: (linkage: external, visibility: default, notEligibleToImport: 0, live: 0, dsoLocal: 1, canAutoHide: 0, importType: definition), insts: 2, funcFlags: (readNone: 0, readOnly: 0, noRecurse: 0, returnDoesNotAlias: 0, noInline: 1, alwaysInline: 0, noUnwind: 0, mayThrow: 0, hasUnknownCall: 0, mustBeUnreachable: 0), allocs: ((versions: (none), memProf: ((type: notcold, stackIds: ()), (type: cold, stackIds: ()), (type: hot, stackIds: ())))))))
; CHECK: ^2 = gv: (guid: 25, summaries: (function: (module: ^0, flags: (linkage: external, visibility: default, notEligibleToImport: 0, live: 0, dsoLocal: 1, canAutoHide: 0, importType: definition), insts: 22, funcFlags: (readNone: 0, readOnly: 0, noRecurse: 1, returnDoesNotAlias: 0, noInline: 1, alwaysInline: 0, noUnwind: 0, mayThrow: 0, hasUnknownCall: 0, mustBeUnreachable: 0), calls: ((callee: ^1)), callsites: ((callee: ^1, clones: (0), stackIds: (8632435727821051414)), (callee: ^1, clones: (0), stackIds: (15025054523792398438, 12345678)), (callee: ^1, clones: (0), stackIds: (23456789))))))
; CHECK: ^3 = gv: (guid: 26, summaries: (function: (module: ^0, flags: (linkage: external, visibility: default, notEligibleToImport: 0, live: 0, dsoLocal: 1, canAutoHide: 0, importType: definition), insts: 2, funcFlags: (readNone: 0, readOnly: 0, noRecurse: 0, returnDoesNotAlias: 0, noInline: 1, alwaysInline: 0, noUnwind: 0, mayThrow: 0, hasUnknownCall: 0, mustBeUnreachable: 0), allocs: ((versions: (cold, notcold), memProf: ((type: notcold, stackIds: (3456789)), (type: cold, stackIds: (456789)))), (versions: (notcold, cold), memProf: ((type: cold, stackIds: (3456789)), (type: notcold, stackIds: (456789))))))))
; CONTEXT: ^3 = gv: (guid: 26, summaries: (function: (module: ^0, flags: (linkage: external, visibility: default, notEligibleToImport: 0, live: 0, dsoLocal: 1, canAutoHide: 0, importType: definition), insts: 2, funcFlags: (readNone: 0, readOnly: 0, noRecurse: 0, returnDoesNotAlias: 0, noInline: 1, alwaysInline: 0, noUnwind: 0, mayThrow: 0, hasUnknownCall: 0, mustBeUnreachable: 0), allocs: ((versions: (cold, notcold), memProf: ((type: notcold, stackIds: (3456789)), (type: cold, stackIds: (456789)))), (versions: (notcold, cold), memProf: ((type: cold, stackIds: (3456789)), (type: notcold, stackIds: (456789))))))))
; NOCONTEXT: ^3 = gv: (guid: 26, summaries: (function: (module: ^0, flags: (linkage: external, visibility: default, notEligibleToImport: 0, live: 0, dsoLocal: 1, canAutoHide: 0, importType: definition), insts: 2, funcFlags: (readNone: 0, readOnly: 0, noRecurse: 0, returnDoesNotAlias: 0, noInline: 1, alwaysInline: 0, noUnwind: 0, mayThrow: 0, hasUnknownCall: 0, mustBeUnreachable: 0), allocs: ((versions: (cold, notcold), memProf: ((type: notcold, stackIds: ()), (type: cold, stackIds: ()))), (versions: (notcold, cold), memProf: ((type: cold, stackIds: ()), (type: notcold, stackIds: ())))))))
; CHECK: ^4 = gv: (guid: 27, summaries: (function: (module: ^0, flags: (linkage: external, visibility: default, notEligibleToImport: 0, live: 0, dsoLocal: 1, canAutoHide: 0, importType: definition), insts: 22, funcFlags: (readNone: 0, readOnly: 0, noRecurse: 1, returnDoesNotAlias: 0, noInline: 1, alwaysInline: 0, noUnwind: 0, mayThrow: 0, hasUnknownCall: 0, mustBeUnreachable: 0), calls: ((callee: ^3)), callsites: ((callee: ^3, clones: (0, 1), stackIds: (3456789)), (callee: ^3, clones: (1, 1), stackIds: (456789))))))
; CHECK: ^5 = gv: (guid: 28, summaries: (function: (module: ^0, flags: (linkage: external, visibility: default, notEligibleToImport: 0, live: 0, dsoLocal: 1, canAutoHide: 0, importType: definition), insts: 22, funcFlags: (readNone: 0, readOnly: 0, noRecurse: 1, returnDoesNotAlias: 0, noInline: 1, alwaysInline: 0, noUnwind: 0, mayThrow: 0, hasUnknownCall: 0, mustBeUnreachable: 0), callsites: ((callee: null, clones: (0), stackIds: (8632435727821051414))))))
1 change: 1 addition & 0 deletions llvm/test/ThinLTO/X86/memprof_direct_recursion.ll
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Expand Up @@ -33,6 +33,7 @@
; RUN: llvm-lto2 run %t/b.o %t/a.o -enable-memprof-context-disambiguation \
; RUN: -supports-hot-cold-new \
; RUN: -thinlto-distributed-indexes \
; RUN: -combined-index-memprof-context \
; RUN: -r=%t/b.o,_Z3fooi,plx \
; RUN: -r=%t/b.o,aliasee,plx \
; RUN: -r=%t/b.o,a \
Expand Down
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