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[ctx_prof] Remove the dependency on the "name" GlobalVariable (llvm#1…
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…05731)

We don't need that name variable for contextual instrumentation, we just
use the function to get its GUID which we pass to the runtime, and rely
on metadata to capture it through the various optimization passes. This
change removes the need for the name global variable.
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@mtrofin @dmpolukhin
mtrofin authored and dmpolukhin committed Sep 2, 2024
1 parent de801a4 commit a5ba3aa
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Showing 5 changed files with 39 additions and 45 deletions.
14 changes: 11 additions & 3 deletions llvm/include/llvm/IR/IntrinsicInst.h
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Original file line number Diff line number Diff line change
Expand Up @@ -1503,11 +1503,19 @@ class InstrProfInstBase : public IntrinsicInst {
return isCounterBase(*Instr) || isMCDCBitmapBase(*Instr);
return false;
}
// The name of the instrumented function.

// The name of the instrumented function, assuming it is a global variable.
GlobalVariable *getName() const {
return cast<GlobalVariable>(
const_cast<Value *>(getArgOperand(0))->stripPointerCasts());
return cast<GlobalVariable>(getNameValue());
}

// The "name" operand of the profile instrumentation instruction - this is the
// operand that can be used to relate the instruction to the function it
// belonged to at instrumentation time.
Value *getNameValue() const {
return const_cast<Value *>(getArgOperand(0))->stripPointerCasts();
}

// The hash of the CFG for the instrumented function.
ConstantInt *getHash() const {
return cast<ConstantInt>(const_cast<Value *>(getArgOperand(1)));
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3 changes: 2 additions & 1 deletion llvm/lib/Transforms/Instrumentation/PGOCtxProfLowering.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -226,7 +226,8 @@ bool CtxInstrumentationLowerer::lowerFunction(Function &F) {

IRBuilder<> Builder(Mark);

Guid = Builder.getInt64(AssignGUIDPass::getGUID(F));
Guid = Builder.getInt64(
AssignGUIDPass::getGUID(cast<Function>(*Mark->getNameValue())));
// The type of the context of this function is now knowable since we have
// NrCallsites and NrCounters. We delcare it here because it's more
// convenient - we have the Builder.
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15 changes: 8 additions & 7 deletions llvm/lib/Transforms/Instrumentation/PGOInstrumentation.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -464,7 +464,7 @@ struct SelectInstVisitor : public InstVisitor<SelectInstVisitor> {
VisitMode Mode = VM_counting; // Visiting mode.
unsigned *CurCtrIdx = nullptr; // Pointer to current counter index.
unsigned TotalNumCtrs = 0; // Total number of counters
GlobalVariable *FuncNameVar = nullptr;
GlobalValue *FuncNameVar = nullptr;
uint64_t FuncHash = 0;
PGOUseFunc *UseFunc = nullptr;
bool HasSingleByteCoverage;
Expand All @@ -482,7 +482,7 @@ struct SelectInstVisitor : public InstVisitor<SelectInstVisitor> {
// Ind is a pointer to the counter index variable; \p TotalNC
// is the total number of counters; \p FNV is the pointer to the
// PGO function name var; \p FHash is the function hash.
void instrumentSelects(unsigned *Ind, unsigned TotalNC, GlobalVariable *FNV,
void instrumentSelects(unsigned *Ind, unsigned TotalNC, GlobalValue *FNV,
uint64_t FHash) {
Mode = VM_instrument;
CurCtrIdx = Ind;
Expand Down Expand Up @@ -901,13 +901,14 @@ void FunctionInstrumenter::instrument() {
SplitIndirectBrCriticalEdges(F, /*IgnoreBlocksWithoutPHI=*/false, BPI, BFI);
}

const bool IsCtxProf = InstrumentationType == PGOInstrumentationType::CTXPROF;
FuncPGOInstrumentation<PGOEdge, PGOBBInfo> FuncInfo(
F, TLI, ComdatMembers, true, BPI, BFI,
F, TLI, ComdatMembers, /*CreateGlobalVar=*/!IsCtxProf, BPI, BFI,
InstrumentationType == PGOInstrumentationType::CSFDO,
shouldInstrumentEntryBB(), PGOBlockCoverage);

auto Name = FuncInfo.FuncNameVar;
auto CFGHash =
auto *const Name = IsCtxProf ? cast<GlobalValue>(&F) : FuncInfo.FuncNameVar;
auto *const CFGHash =
ConstantInt::get(Type::getInt64Ty(M.getContext()), FuncInfo.FunctionHash);
// Make sure that pointer to global is passed in with zero addrspace
// This is relevant during GPU profiling
Expand All @@ -929,7 +930,7 @@ void FunctionInstrumenter::instrument() {
unsigned NumCounters =
InstrumentBBs.size() + FuncInfo.SIVisitor.getNumOfSelectInsts();

if (InstrumentationType == PGOInstrumentationType::CTXPROF) {
if (IsCtxProf) {
auto *CSIntrinsic =
Intrinsic::getDeclaration(&M, Intrinsic::instrprof_callsite);
// We want to count the instrumentable callsites, then instrument them. This
Expand Down Expand Up @@ -995,7 +996,7 @@ void FunctionInstrumenter::instrument() {
}

// Now instrument select instructions:
FuncInfo.SIVisitor.instrumentSelects(&I, NumCounters, FuncInfo.FuncNameVar,
FuncInfo.SIVisitor.instrumentSelects(&I, NumCounters, Name,
FuncInfo.FunctionHash);
assert(I == NumCounters);

Expand Down
41 changes: 14 additions & 27 deletions llvm/test/Transforms/PGOProfile/ctx-instrumentation.ll
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Original file line number Diff line number Diff line change
Expand Up @@ -9,19 +9,6 @@
declare void @bar()

;.
; INSTRUMENT: @__profn_foo = private constant [3 x i8] c"foo"
; INSTRUMENT: @__profn_an_entrypoint = private constant [13 x i8] c"an_entrypoint"
; INSTRUMENT: @__profn_another_entrypoint_no_callees = private constant [29 x i8] c"another_entrypoint_no_callees"
; INSTRUMENT: @__profn_simple = private constant [6 x i8] c"simple"
; INSTRUMENT: @__profn_no_callsites = private constant [12 x i8] c"no_callsites"
; INSTRUMENT: @__profn_no_counters = private constant [11 x i8] c"no_counters"
;.
; LOWERING: @__profn_foo = private constant [3 x i8] c"foo"
; LOWERING: @__profn_an_entrypoint = private constant [13 x i8] c"an_entrypoint"
; LOWERING: @__profn_another_entrypoint_no_callees = private constant [29 x i8] c"another_entrypoint_no_callees"
; LOWERING: @__profn_simple = private constant [6 x i8] c"simple"
; LOWERING: @__profn_no_callsites = private constant [12 x i8] c"no_callsites"
; LOWERING: @__profn_no_counters = private constant [11 x i8] c"no_counters"
; LOWERING: @an_entrypoint_ctx_root = global { ptr, ptr, ptr, i8 } zeroinitializer
; LOWERING: @another_entrypoint_no_callees_ctx_root = global { ptr, ptr, ptr, i8 } zeroinitializer
; LOWERING: @__llvm_ctx_profile_callsite = external hidden thread_local global ptr
Expand All @@ -30,16 +17,16 @@ declare void @bar()
define void @foo(i32 %a, ptr %fct) {
; INSTRUMENT-LABEL: define void @foo(
; INSTRUMENT-SAME: i32 [[A:%.*]], ptr [[FCT:%.*]]) {
; INSTRUMENT-NEXT: call void @llvm.instrprof.increment(ptr @__profn_foo, i64 728453322856651412, i32 2, i32 0)
; INSTRUMENT-NEXT: call void @llvm.instrprof.increment(ptr @foo, i64 728453322856651412, i32 2, i32 0)
; INSTRUMENT-NEXT: [[T:%.*]] = icmp eq i32 [[A]], 0
; INSTRUMENT-NEXT: br i1 [[T]], label [[YES:%.*]], label [[NO:%.*]]
; INSTRUMENT: yes:
; INSTRUMENT-NEXT: call void @llvm.instrprof.increment(ptr @__profn_foo, i64 728453322856651412, i32 2, i32 1)
; INSTRUMENT-NEXT: call void @llvm.instrprof.callsite(ptr @__profn_foo, i64 728453322856651412, i32 2, i32 0, ptr [[FCT]])
; INSTRUMENT-NEXT: call void @llvm.instrprof.increment(ptr @foo, i64 728453322856651412, i32 2, i32 1)
; INSTRUMENT-NEXT: call void @llvm.instrprof.callsite(ptr @foo, i64 728453322856651412, i32 2, i32 0, ptr [[FCT]])
; INSTRUMENT-NEXT: call void [[FCT]](i32 [[A]])
; INSTRUMENT-NEXT: br label [[EXIT:%.*]]
; INSTRUMENT: no:
; INSTRUMENT-NEXT: call void @llvm.instrprof.callsite(ptr @__profn_foo, i64 728453322856651412, i32 2, i32 1, ptr @bar)
; INSTRUMENT-NEXT: call void @llvm.instrprof.callsite(ptr @foo, i64 728453322856651412, i32 2, i32 1, ptr @bar)
; INSTRUMENT-NEXT: call void @bar()
; INSTRUMENT-NEXT: br label [[EXIT]]
; INSTRUMENT: exit:
Expand Down Expand Up @@ -92,12 +79,12 @@ exit:
define void @an_entrypoint(i32 %a) {
; INSTRUMENT-LABEL: define void @an_entrypoint(
; INSTRUMENT-SAME: i32 [[A:%.*]]) {
; INSTRUMENT-NEXT: call void @llvm.instrprof.increment(ptr @__profn_an_entrypoint, i64 784007058953177093, i32 2, i32 0)
; INSTRUMENT-NEXT: call void @llvm.instrprof.increment(ptr @an_entrypoint, i64 784007058953177093, i32 2, i32 0)
; INSTRUMENT-NEXT: [[T:%.*]] = icmp eq i32 [[A]], 0
; INSTRUMENT-NEXT: br i1 [[T]], label [[YES:%.*]], label [[NO:%.*]]
; INSTRUMENT: yes:
; INSTRUMENT-NEXT: call void @llvm.instrprof.increment(ptr @__profn_an_entrypoint, i64 784007058953177093, i32 2, i32 1)
; INSTRUMENT-NEXT: call void @llvm.instrprof.callsite(ptr @__profn_an_entrypoint, i64 784007058953177093, i32 1, i32 0, ptr @foo)
; INSTRUMENT-NEXT: call void @llvm.instrprof.increment(ptr @an_entrypoint, i64 784007058953177093, i32 2, i32 1)
; INSTRUMENT-NEXT: call void @llvm.instrprof.callsite(ptr @an_entrypoint, i64 784007058953177093, i32 1, i32 0, ptr @foo)
; INSTRUMENT-NEXT: call void @foo(i32 1, ptr null)
; INSTRUMENT-NEXT: ret void
; INSTRUMENT: no:
Expand Down Expand Up @@ -144,11 +131,11 @@ no:
define void @another_entrypoint_no_callees(i32 %a) {
; INSTRUMENT-LABEL: define void @another_entrypoint_no_callees(
; INSTRUMENT-SAME: i32 [[A:%.*]]) {
; INSTRUMENT-NEXT: call void @llvm.instrprof.increment(ptr @__profn_another_entrypoint_no_callees, i64 784007058953177093, i32 2, i32 0)
; INSTRUMENT-NEXT: call void @llvm.instrprof.increment(ptr @another_entrypoint_no_callees, i64 784007058953177093, i32 2, i32 0)
; INSTRUMENT-NEXT: [[T:%.*]] = icmp eq i32 [[A]], 0
; INSTRUMENT-NEXT: br i1 [[T]], label [[YES:%.*]], label [[NO:%.*]]
; INSTRUMENT: yes:
; INSTRUMENT-NEXT: call void @llvm.instrprof.increment(ptr @__profn_another_entrypoint_no_callees, i64 784007058953177093, i32 2, i32 1)
; INSTRUMENT-NEXT: call void @llvm.instrprof.increment(ptr @another_entrypoint_no_callees, i64 784007058953177093, i32 2, i32 1)
; INSTRUMENT-NEXT: ret void
; INSTRUMENT: no:
; INSTRUMENT-NEXT: ret void
Expand Down Expand Up @@ -184,7 +171,7 @@ no:
define void @simple(i32 %a) {
; INSTRUMENT-LABEL: define void @simple(
; INSTRUMENT-SAME: i32 [[A:%.*]]) {
; INSTRUMENT-NEXT: call void @llvm.instrprof.increment(ptr @__profn_simple, i64 742261418966908927, i32 1, i32 0)
; INSTRUMENT-NEXT: call void @llvm.instrprof.increment(ptr @simple, i64 742261418966908927, i32 1, i32 0)
; INSTRUMENT-NEXT: ret void
;
; LOWERING-LABEL: define void @simple(
Expand All @@ -202,11 +189,11 @@ define void @simple(i32 %a) {
define i32 @no_callsites(i32 %a) {
; INSTRUMENT-LABEL: define i32 @no_callsites(
; INSTRUMENT-SAME: i32 [[A:%.*]]) {
; INSTRUMENT-NEXT: call void @llvm.instrprof.increment(ptr @__profn_no_callsites, i64 784007058953177093, i32 2, i32 0)
; INSTRUMENT-NEXT: call void @llvm.instrprof.increment(ptr @no_callsites, i64 784007058953177093, i32 2, i32 0)
; INSTRUMENT-NEXT: [[C:%.*]] = icmp eq i32 [[A]], 0
; INSTRUMENT-NEXT: br i1 [[C]], label [[YES:%.*]], label [[NO:%.*]]
; INSTRUMENT: yes:
; INSTRUMENT-NEXT: call void @llvm.instrprof.increment(ptr @__profn_no_callsites, i64 784007058953177093, i32 2, i32 1)
; INSTRUMENT-NEXT: call void @llvm.instrprof.increment(ptr @no_callsites, i64 784007058953177093, i32 2, i32 1)
; INSTRUMENT-NEXT: ret i32 1
; INSTRUMENT: no:
; INSTRUMENT-NEXT: ret i32 0
Expand Down Expand Up @@ -238,8 +225,8 @@ no:

define void @no_counters() {
; INSTRUMENT-LABEL: define void @no_counters() {
; INSTRUMENT-NEXT: call void @llvm.instrprof.increment(ptr @__profn_no_counters, i64 742261418966908927, i32 1, i32 0)
; INSTRUMENT-NEXT: call void @llvm.instrprof.callsite(ptr @__profn_no_counters, i64 742261418966908927, i32 1, i32 0, ptr @bar)
; INSTRUMENT-NEXT: call void @llvm.instrprof.increment(ptr @no_counters, i64 742261418966908927, i32 1, i32 0)
; INSTRUMENT-NEXT: call void @llvm.instrprof.callsite(ptr @no_counters, i64 742261418966908927, i32 1, i32 0, ptr @bar)
; INSTRUMENT-NEXT: call void @bar()
; INSTRUMENT-NEXT: ret void
;
Expand Down
11 changes: 4 additions & 7 deletions llvm/test/Transforms/PGOProfile/ctx-prof-use-prelink.ll
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Original file line number Diff line number Diff line change
Expand Up @@ -7,22 +7,19 @@

declare void @bar()

;.
; CHECK: @__profn_foo = private constant [3 x i8] c"foo"
;.
define void @foo(i32 %a, ptr %fct) {
; CHECK-LABEL: define void @foo(
; CHECK-SAME: i32 [[A:%.*]], ptr [[FCT:%.*]]) local_unnamed_addr !guid [[META0:![0-9]+]] {
; CHECK-NEXT: call void @llvm.instrprof.increment(ptr @__profn_foo, i64 728453322856651412, i32 2, i32 0)
; CHECK-NEXT: call void @llvm.instrprof.increment(ptr @foo, i64 728453322856651412, i32 2, i32 0)
; CHECK-NEXT: [[T:%.*]] = icmp eq i32 [[A]], 0
; CHECK-NEXT: br i1 [[T]], label %[[YES:.*]], label %[[NO:.*]]
; CHECK: [[YES]]:
; CHECK-NEXT: call void @llvm.instrprof.increment(ptr @__profn_foo, i64 728453322856651412, i32 2, i32 1)
; CHECK-NEXT: call void @llvm.instrprof.callsite(ptr @__profn_foo, i64 728453322856651412, i32 2, i32 0, ptr [[FCT]])
; CHECK-NEXT: call void @llvm.instrprof.increment(ptr @foo, i64 728453322856651412, i32 2, i32 1)
; CHECK-NEXT: call void @llvm.instrprof.callsite(ptr @foo, i64 728453322856651412, i32 2, i32 0, ptr [[FCT]])
; CHECK-NEXT: call void [[FCT]](i32 0)
; CHECK-NEXT: br label %[[EXIT:.*]]
; CHECK: [[NO]]:
; CHECK-NEXT: call void @llvm.instrprof.callsite(ptr @__profn_foo, i64 728453322856651412, i32 2, i32 1, ptr @bar)
; CHECK-NEXT: call void @llvm.instrprof.callsite(ptr @foo, i64 728453322856651412, i32 2, i32 1, ptr @bar)
; CHECK-NEXT: call void @bar()
; CHECK-NEXT: br label %[[EXIT]]
; CHECK: [[EXIT]]:
Expand Down

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