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[clang][fmv] Drop .ifunc from target_version's entrypoint's mangling #81194

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merged 4 commits into from
Feb 9, 2024
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[clang][fmv] Drop .ifunc from target_version's entrypoint's mangling #81194

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92aef5a
[clang][fmv] Drop .ifunc from target_version's entrypoint's mangling
jroelofs Feb 8, 2024
e59dfe3
clang-format
jroelofs Feb 8, 2024
24692b0
copy the note about .ifunc aliases from target_clones's docs
jroelofs Feb 8, 2024
3115821
if -> switch
jroelofs Feb 9, 2024
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4 changes: 4 additions & 0 deletions clang/include/clang/AST/Decl.h
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Expand Up @@ -2619,6 +2619,10 @@ class FunctionDecl : public DeclaratorDecl,
/// the target-clones functionality.
bool isTargetClonesMultiVersion() const;

/// True if this function is a multiversioned dispatch function as a part of
/// the target-version functionality.
bool isTargetVersionMultiVersion() const;

/// \brief Get the associated-constraints of this function declaration.
/// Currently, this will either be a vector of size 1 containing the
/// trailing-requires-clause or an empty vector.
Expand Down
8 changes: 8 additions & 0 deletions clang/include/clang/Basic/AttrDocs.td
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Expand Up @@ -2517,6 +2517,14 @@ function it instructs compiler to emit multiple function versions based on
priority and target features availability. One of the versions is always
( implicitly or explicitly ) the ``default`` (fallback). Attribute strings can
contain dependent features names joined by the "+" sign.

For targets that support the GNU indirect function (IFUNC) feature, dispatch
is performed by emitting an indirect function that is resolved to the appropriate
target clone at load time. The indirect function is given the name the
multiversioned function would have if it had been declared without the attribute.
For backward compatibility with earlier Clang releases, a function alias with an
``.ifunc`` suffix is also emitted. The ``.ifunc`` suffixed symbol is a deprecated
feature and support for it may be removed in the future.
}];
}

Expand Down
4 changes: 4 additions & 0 deletions clang/lib/AST/Decl.cpp
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Expand Up @@ -3541,6 +3541,10 @@ bool FunctionDecl::isTargetClonesMultiVersion() const {
return isMultiVersion() && hasAttr<TargetClonesAttr>();
}

bool FunctionDecl::isTargetVersionMultiVersion() const {
return isMultiVersion() && hasAttr<TargetVersionAttr>();
}

void
FunctionDecl::setPreviousDeclaration(FunctionDecl *PrevDecl) {
redeclarable_base::setPreviousDecl(PrevDecl);
Expand Down
16 changes: 14 additions & 2 deletions clang/lib/CodeGen/CodeGenModule.cpp
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Expand Up @@ -30,6 +30,7 @@
#include "clang/AST/ASTContext.h"
#include "clang/AST/ASTLambda.h"
#include "clang/AST/CharUnits.h"
#include "clang/AST/Decl.h"
#include "clang/AST/DeclCXX.h"
#include "clang/AST/DeclObjC.h"
#include "clang/AST/DeclTemplate.h"
Expand Down Expand Up @@ -4212,7 +4213,8 @@ void CodeGenModule::emitMultiVersionFunctions() {
llvm::Constant *ResolverConstant = GetOrCreateMultiVersionResolver(GD);
if (auto *IFunc = dyn_cast<llvm::GlobalIFunc>(ResolverConstant)) {
ResolverConstant = IFunc->getResolver();
if (FD->isTargetClonesMultiVersion()) {
if (FD->isTargetClonesMultiVersion() ||
FD->isTargetVersionMultiVersion()) {
const CGFunctionInfo &FI = getTypes().arrangeGlobalDeclaration(GD);
llvm::FunctionType *DeclTy = getTypes().GetFunctionType(FI);
std::string MangledName = getMangledNameImpl(
Expand Down Expand Up @@ -4393,8 +4395,18 @@ llvm::Constant *CodeGenModule::GetOrCreateMultiVersionResolver(GlobalDecl GD) {
// a separate resolver).
std::string ResolverName = MangledName;
if (getTarget().supportsIFunc()) {
if (!FD->isTargetClonesMultiVersion())
switch (FD->getMultiVersionKind()) {
case MultiVersionKind::None:
llvm_unreachable("unexpected MultiVersionKind::None for resolver");
case MultiVersionKind::Target:
case MultiVersionKind::CPUSpecific:
case MultiVersionKind::CPUDispatch:
ResolverName += ".ifunc";
break;
case MultiVersionKind::TargetClones:
case MultiVersionKind::TargetVersion:
break;
}
} else if (FD->isTargetMultiVersion()) {
ResolverName += ".resolver";
}
Expand Down
129 changes: 68 additions & 61 deletions clang/test/CodeGen/attr-target-version.c
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Expand Up @@ -90,13 +90,20 @@ int hoo(void) {

//.
// CHECK: @__aarch64_cpu_features = external dso_local global { i64 }
// CHECK: @fmv.ifunc = weak_odr ifunc i32 (), ptr @fmv.resolver
// CHECK: @fmv_one.ifunc = weak_odr ifunc i32 (), ptr @fmv_one.resolver
// CHECK: @fmv_two.ifunc = weak_odr ifunc i32 (), ptr @fmv_two.resolver
// CHECK: @fmv_e.ifunc = weak_odr ifunc i32 (), ptr @fmv_e.resolver
// CHECK: @fmv_c.ifunc = weak_odr ifunc void (), ptr @fmv_c.resolver
// CHECK: @fmv_inline.ifunc = weak_odr ifunc i32 (), ptr @fmv_inline.resolver
// CHECK: @fmv_d.ifunc = internal ifunc i32 (), ptr @fmv_d.resolver
// CHECK: @fmv.ifunc = weak_odr alias i32 (), ptr @fmv
// CHECK: @fmv_one.ifunc = weak_odr alias i32 (), ptr @fmv_one
// CHECK: @fmv_two.ifunc = weak_odr alias i32 (), ptr @fmv_two
// CHECK: @fmv_e.ifunc = weak_odr alias i32 (), ptr @fmv_e
// CHECK: @fmv_inline.ifunc = weak_odr alias i32 (), ptr @fmv_inline
// CHECK: @fmv_d.ifunc = internal alias i32 (), ptr @fmv_d
// CHECK: @fmv_c.ifunc = weak_odr alias void (), ptr @fmv_c
// CHECK: @fmv = weak_odr ifunc i32 (), ptr @fmv.resolver
// CHECK: @fmv_one = weak_odr ifunc i32 (), ptr @fmv_one.resolver
// CHECK: @fmv_two = weak_odr ifunc i32 (), ptr @fmv_two.resolver
// CHECK: @fmv_e = weak_odr ifunc i32 (), ptr @fmv_e.resolver
// CHECK: @fmv_inline = weak_odr ifunc i32 (), ptr @fmv_inline.resolver
// CHECK: @fmv_d = internal ifunc i32 (), ptr @fmv_d.resolver
// CHECK: @fmv_c = weak_odr ifunc void (), ptr @fmv_c.resolver
//.
// CHECK: Function Attrs: noinline nounwind optnone
// CHECK-LABEL: define {{[^@]+}}@fmv._MrngMflagmMfp16fml
Expand All @@ -105,6 +112,32 @@ int hoo(void) {
// CHECK-NEXT: ret i32 1
//
//
// CHECK: Function Attrs: noinline nounwind optnone
// CHECK-LABEL: define {{[^@]+}}@fmv_one._MsimdMls64
// CHECK-SAME: () #[[ATTR1:[0-9]+]] {
// CHECK-NEXT: entry:
// CHECK-NEXT: ret i32 1
//
//
// CHECK: Function Attrs: noinline nounwind optnone
// CHECK-LABEL: define {{[^@]+}}@fmv_two._Mfp
// CHECK-SAME: () #[[ATTR1]] {
// CHECK-NEXT: entry:
// CHECK-NEXT: ret i32 1
//
//
// CHECK: Function Attrs: noinline nounwind optnone
// CHECK-LABEL: define {{[^@]+}}@foo
// CHECK-SAME: () #[[ATTR2:[0-9]+]] {
// CHECK-NEXT: entry:
// CHECK-NEXT: [[CALL:%.*]] = call i32 @fmv()
// CHECK-NEXT: [[CALL1:%.*]] = call i32 @fmv_one()
// CHECK-NEXT: [[ADD:%.*]] = add nsw i32 [[CALL]], [[CALL1]]
// CHECK-NEXT: [[CALL2:%.*]] = call i32 @fmv_two()
// CHECK-NEXT: [[ADD3:%.*]] = add nsw i32 [[ADD]], [[CALL2]]
// CHECK-NEXT: ret i32 [[ADD3]]
//
//
// CHECK-LABEL: define {{[^@]+}}@fmv.resolver() comdat {
// CHECK-NEXT: resolver_entry:
// CHECK-NEXT: call void @__init_cpu_features_resolver()
Expand Down Expand Up @@ -183,42 +216,16 @@ int hoo(void) {
// CHECK-NEXT: ret ptr @fmv.default
//
//
// CHECK: Function Attrs: noinline nounwind optnone
// CHECK-LABEL: define {{[^@]+}}@fmv_one._MsimdMls64
// CHECK-SAME: () #[[ATTR1:[0-9]+]] {
// CHECK-NEXT: entry:
// CHECK-NEXT: ret i32 1
//
//
// CHECK-LABEL: define {{[^@]+}}@fmv_one.resolver() comdat {
// CHECK-NEXT: resolver_entry:
// CHECK-NEXT: ret ptr @fmv_one._MsimdMls64
//
//
// CHECK: Function Attrs: noinline nounwind optnone
// CHECK-LABEL: define {{[^@]+}}@fmv_two._Mfp
// CHECK-SAME: () #[[ATTR1]] {
// CHECK-NEXT: entry:
// CHECK-NEXT: ret i32 1
//
//
// CHECK-LABEL: define {{[^@]+}}@fmv_two.resolver() comdat {
// CHECK-NEXT: resolver_entry:
// CHECK-NEXT: ret ptr @fmv_two._MsimdMfp16
//
//
// CHECK: Function Attrs: noinline nounwind optnone
// CHECK-LABEL: define {{[^@]+}}@foo
// CHECK-SAME: () #[[ATTR2:[0-9]+]] {
// CHECK-NEXT: entry:
// CHECK-NEXT: [[CALL:%.*]] = call i32 @fmv.ifunc()
// CHECK-NEXT: [[CALL1:%.*]] = call i32 @fmv_one.ifunc()
// CHECK-NEXT: [[ADD:%.*]] = add nsw i32 [[CALL]], [[CALL1]]
// CHECK-NEXT: [[CALL2:%.*]] = call i32 @fmv_two.ifunc()
// CHECK-NEXT: [[ADD3:%.*]] = add nsw i32 [[ADD]], [[CALL2]]
// CHECK-NEXT: ret i32 [[ADD3]]
//
//
// CHECK-LABEL: define {{[^@]+}}@fmv_e.resolver() comdat {
// CHECK-NEXT: resolver_entry:
// CHECK-NEXT: ret ptr @fmv_e._Mls64
Expand All @@ -238,28 +245,14 @@ int hoo(void) {
// CHECK-NEXT: ret void
//
//
// CHECK-LABEL: define {{[^@]+}}@fmv_c.resolver() comdat {
// CHECK-NEXT: resolver_entry:
// CHECK-NEXT: call void @__init_cpu_features_resolver()
// CHECK-NEXT: [[TMP0:%.*]] = load i64, ptr @__aarch64_cpu_features, align 8
// CHECK-NEXT: [[TMP1:%.*]] = and i64 [[TMP0]], 281474976710656
// CHECK-NEXT: [[TMP2:%.*]] = icmp eq i64 [[TMP1]], 281474976710656
// CHECK-NEXT: [[TMP3:%.*]] = and i1 true, [[TMP2]]
// CHECK-NEXT: br i1 [[TMP3]], label [[RESOLVER_RETURN:%.*]], label [[RESOLVER_ELSE:%.*]]
// CHECK: resolver_return:
// CHECK-NEXT: ret ptr @fmv_c._Mssbs
// CHECK: resolver_else:
// CHECK-NEXT: ret ptr @fmv_c.default
//
//
// CHECK: Function Attrs: noinline nounwind optnone
// CHECK-LABEL: define {{[^@]+}}@goo
// CHECK-SAME: () #[[ATTR2]] {
// CHECK-NEXT: entry:
// CHECK-NEXT: [[CALL:%.*]] = call i32 @fmv_inline.ifunc()
// CHECK-NEXT: [[CALL1:%.*]] = call i32 @fmv_e.ifunc()
// CHECK-NEXT: [[CALL2:%.*]] = call i32 @fmv_d.ifunc()
// CHECK-NEXT: call void @fmv_c.ifunc()
// CHECK-NEXT: [[CALL:%.*]] = call i32 @fmv_inline()
// CHECK-NEXT: [[CALL1:%.*]] = call i32 @fmv_e()
// CHECK-NEXT: [[CALL2:%.*]] = call i32 @fmv_d()
// CHECK-NEXT: call void @fmv_c()
// CHECK-NEXT: [[CALL3:%.*]] = call i32 @fmv_default()
// CHECK-NEXT: ret i32 [[CALL3]]
//
Expand Down Expand Up @@ -412,6 +405,20 @@ int hoo(void) {
// CHECK-NEXT: ret ptr @fmv_d.default
//
//
// CHECK-LABEL: define {{[^@]+}}@fmv_c.resolver() comdat {
// CHECK-NEXT: resolver_entry:
// CHECK-NEXT: call void @__init_cpu_features_resolver()
// CHECK-NEXT: [[TMP0:%.*]] = load i64, ptr @__aarch64_cpu_features, align 8
// CHECK-NEXT: [[TMP1:%.*]] = and i64 [[TMP0]], 281474976710656
// CHECK-NEXT: [[TMP2:%.*]] = icmp eq i64 [[TMP1]], 281474976710656
// CHECK-NEXT: [[TMP3:%.*]] = and i1 true, [[TMP2]]
// CHECK-NEXT: br i1 [[TMP3]], label [[RESOLVER_RETURN:%.*]], label [[RESOLVER_ELSE:%.*]]
// CHECK: resolver_return:
// CHECK-NEXT: ret ptr @fmv_c._Mssbs
// CHECK: resolver_else:
// CHECK-NEXT: ret ptr @fmv_c.default
//
//
// CHECK: Function Attrs: noinline nounwind optnone
// CHECK-LABEL: define {{[^@]+}}@recur
// CHECK-SAME: () #[[ATTR2]] {
Expand All @@ -437,9 +444,9 @@ int hoo(void) {
// CHECK-NEXT: entry:
// CHECK-NEXT: [[FP1:%.*]] = alloca ptr, align 8
// CHECK-NEXT: [[FP2:%.*]] = alloca ptr, align 8
// CHECK-NEXT: call void @f(ptr noundef @fmv.ifunc)
// CHECK-NEXT: store ptr @fmv.ifunc, ptr [[FP1]], align 8
// CHECK-NEXT: store ptr @fmv.ifunc, ptr [[FP2]], align 8
// CHECK-NEXT: call void @f(ptr noundef @fmv)
// CHECK-NEXT: store ptr @fmv, ptr [[FP1]], align 8
// CHECK-NEXT: store ptr @fmv, ptr [[FP2]], align 8
// CHECK-NEXT: [[TMP0:%.*]] = load ptr, ptr [[FP1]], align 8
// CHECK-NEXT: [[CALL:%.*]] = call i32 [[TMP0]]()
// CHECK-NEXT: [[TMP1:%.*]] = load ptr, ptr [[FP2]], align 8
Expand Down Expand Up @@ -561,13 +568,6 @@ int hoo(void) {
//
//
// CHECK: Function Attrs: noinline nounwind optnone
// CHECK-LABEL: define {{[^@]+}}@fmv_c.default
// CHECK-SAME: () #[[ATTR2]] {
// CHECK-NEXT: entry:
// CHECK-NEXT: ret void
//
//
// CHECK: Function Attrs: noinline nounwind optnone
// CHECK-LABEL: define {{[^@]+}}@fmv_inline._Msha1MpmullMf64mm
// CHECK-SAME: () #[[ATTR12:[0-9]+]] {
// CHECK-NEXT: entry:
Expand Down Expand Up @@ -700,6 +700,13 @@ int hoo(void) {
// CHECK-NEXT: ret i32 1
//
//
// CHECK: Function Attrs: noinline nounwind optnone
// CHECK-LABEL: define {{[^@]+}}@fmv_c.default
// CHECK-SAME: () #[[ATTR2]] {
// CHECK-NEXT: entry:
// CHECK-NEXT: ret void
//
//
// CHECK-NOFMV: Function Attrs: noinline nounwind optnone
// CHECK-NOFMV-LABEL: define {{[^@]+}}@fmv
// CHECK-NOFMV-SAME: () #[[ATTR0:[0-9]+]] {
Expand Down
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