[clang] [Clang][HTO] Add clang attribute for propagating llvm-level information (PR #83059)
William Moses via cfe-commits
cfe-commits at lists.llvm.org
Mon Feb 26 16:56:49 PST 2024
https://github.com/wsmoses updated https://github.com/llvm/llvm-project/pull/83059
>From c01b559836ca62648c5f95a6441888514347a1ea Mon Sep 17 00:00:00 2001
From: "William S. Moses" <gh at wsmoses.com>
Date: Mon, 26 Feb 2024 16:17:55 -0500
Subject: [PATCH 1/2] [Clang][HTO] Add clang attribute for propagating
llvm-level information
---
clang/include/clang/Basic/Attr.td | 7 +++++++
clang/include/clang/Basic/AttrDocs.td | 13 +++++++++++++
clang/lib/CodeGen/CGCall.cpp | 16 ++++++++++++++++
clang/lib/CodeGen/CodeGenFunction.cpp | 19 +++++++++++++++++++
clang/test/CodeGen/attr-llvmfn.c | 14 ++++++++++++++
5 files changed, 69 insertions(+)
create mode 100644 clang/test/CodeGen/attr-llvmfn.c
diff --git a/clang/include/clang/Basic/Attr.td b/clang/include/clang/Basic/Attr.td
index fa191c7378dba4..044f4fada3590f 100644
--- a/clang/include/clang/Basic/Attr.td
+++ b/clang/include/clang/Basic/Attr.td
@@ -2211,6 +2211,13 @@ def AllocAlign : InheritableAttr {
let Documentation = [AllocAlignDocs];
}
+def LLVMFuncAttr : InheritableAttr {
+ let Spellings = [Clang<"llvm_fn_attr">];
+ let Args = [StringArgument<"LLVMAttrName">, StringArgument<"LLVMAttrValue">];
+ let Documentation = [LLVMFuncAttrDocs];
+ let InheritEvenIfAlreadyPresent = 1;
+}
+
def NoReturn : InheritableAttr {
let Spellings = [GCC<"noreturn">, Declspec<"noreturn">];
// FIXME: Does GCC allow this on the function instead?
diff --git a/clang/include/clang/Basic/AttrDocs.td b/clang/include/clang/Basic/AttrDocs.td
index b96fbddd51154c..3f93bb6d6fc648 100644
--- a/clang/include/clang/Basic/AttrDocs.td
+++ b/clang/include/clang/Basic/AttrDocs.td
@@ -781,6 +781,19 @@ pointer is not sufficiently aligned.
}];
}
+def LLVMFuncAttrDocs : Documentation {
+ let Category = DocCatFunction;
+ let Content = [{
+Use ``__attribute__((llvm_fn_attr(attr_name, attr_value)))`` on a function to specify an LLVM function attribute that will be added to this function.
+
+Note that uses of this attribute are highly compiler specific as the meaning and availability of LLVM attributes may change between compiler versions.
+
+This attribute is only intended for advanced users who need to specify specific information only available in LLVM attributes. Use of attributes which are not tied to a specific version of Clang (e.g. pure) should be preferred when available.
+
+The first arugment is a string representing the name of the LLVM attribute to be applied and the second arugment is a string representing its value.
+ }];
+}
+
def EnableIfDocs : Documentation {
let Category = DocCatFunction;
let Content = [{
diff --git a/clang/lib/CodeGen/CGCall.cpp b/clang/lib/CodeGen/CGCall.cpp
index d05cf1c6e1814e..4725dce607eee9 100644
--- a/clang/lib/CodeGen/CGCall.cpp
+++ b/clang/lib/CodeGen/CGCall.cpp
@@ -2465,6 +2465,22 @@ void CodeGenModule::ConstructAttributeList(StringRef Name,
if (TargetDecl->hasAttr<ArmLocallyStreamingAttr>())
FuncAttrs.addAttribute("aarch64_pstate_sm_body");
+
+ for (auto Attr : TargetDecl->specific_attrs<attr::LLVMFuncAttr>()) {
+ auto name = Attr->getLLVMAttrName();
+ auto value = Attr->getLLVMAttrValue();
+
+ Attribute Attr;
+ auto EnumAttr = llvm::Attribute::getAttrKindFromName(name);
+ if (EnumAttr == llvm::Attribute::None)
+ Attr = llvm::Attribute::get(getLLVMContext(), name, value);
+ else {
+ assert(value.size() == 0 &&
+ "enum attribute does not support value yet");
+ Attr = llvm::Attribute::get(getLLVMContext(), EnumAttr);
+ }
+ FuncAttrs.addAttribute(Attr);
+ }
}
// Attach "no-builtins" attributes to:
diff --git a/clang/lib/CodeGen/CodeGenFunction.cpp b/clang/lib/CodeGen/CodeGenFunction.cpp
index 1ad905078d349c..5d0edd4bbf83c7 100644
--- a/clang/lib/CodeGen/CodeGenFunction.cpp
+++ b/clang/lib/CodeGen/CodeGenFunction.cpp
@@ -831,6 +831,25 @@ void CodeGenFunction::StartFunction(GlobalDecl GD, QualType RetTy,
FD->getBody()->getStmtClass() == Stmt::CoroutineBodyStmtClass)
SanOpts.Mask &= ~SanitizerKind::Null;
+ if (D) {
+ for (auto Attr :
+ template TargetDecl->specific_attrs<attr::LLVMFuncAttr>()) {
+ auto name = Attr->getLLVMAttrName();
+ auto value = Attr->getLLVMAttrValue();
+
+ Attribute Attr;
+ auto EnumAttr = llvm::Attribute::getAttrKindFromName(name);
+ if (EnumAttr == llvm::Attribute::None)
+ Attr = llvm::Attribute::get(getLLVMContext(), name, value);
+ else {
+ assert(value.size() == 0 &&
+ "enum attribute does not support value yet");
+ Attr = llvm::Attribute::get(getLLVMContext(), EnumAttr);
+ }
+ Fn->addFnAttr(Attr);
+ }
+ }
+
// Apply xray attributes to the function (as a string, for now)
bool AlwaysXRayAttr = false;
if (const auto *XRayAttr = D ? D->getAttr<XRayInstrumentAttr>() : nullptr) {
diff --git a/clang/test/CodeGen/attr-llvmfn.c b/clang/test/CodeGen/attr-llvmfn.c
new file mode 100644
index 00000000000000..72f14a726f795e
--- /dev/null
+++ b/clang/test/CodeGen/attr-llvmfn.c
@@ -0,0 +1,14 @@
+// RUN: %clang_cc1 -debug-info-kind=limited -emit-llvm -o - | FileCheck %s
+
+void t1() __attribute__((llvm_fn_attr("custom_attr", "custom_value"), llvm_fn_attr("second_attr", "second_value")));
+
+void t1()
+{
+}
+
+void t2();
+
+void t3() {
+ t2() ____attribute__((llvm_fn_attr("custom_attr", "custom_value"), llvm_fn_attr("second_attr", "second_value")));
+}
+
>From cb87c493905b383b19be82fbf87cef607e659cd6 Mon Sep 17 00:00:00 2001
From: Billy Moses <gh at wsmoses.com>
Date: Mon, 26 Feb 2024 22:39:15 +0000
Subject: [PATCH 2/2] fixup
---
clang/include/clang/Basic/Attr.td | 2 +-
clang/lib/CodeGen/CGCall.cpp | 12 ++++++------
clang/lib/CodeGen/CodeGenFunction.cpp | 10 +++++-----
clang/lib/Sema/SemaDeclAttr.cpp | 17 +++++++++++++++++
clang/test/CodeGen/attr-llvmfn.c | 13 +++++++------
5 files changed, 36 insertions(+), 18 deletions(-)
diff --git a/clang/include/clang/Basic/Attr.td b/clang/include/clang/Basic/Attr.td
index 044f4fada3590f..5b792db5c7435f 100644
--- a/clang/include/clang/Basic/Attr.td
+++ b/clang/include/clang/Basic/Attr.td
@@ -2211,7 +2211,7 @@ def AllocAlign : InheritableAttr {
let Documentation = [AllocAlignDocs];
}
-def LLVMFuncAttr : InheritableAttr {
+def LLVMFuncAttr : DeclOrStmtAttr {
let Spellings = [Clang<"llvm_fn_attr">];
let Args = [StringArgument<"LLVMAttrName">, StringArgument<"LLVMAttrValue">];
let Documentation = [LLVMFuncAttrDocs];
diff --git a/clang/lib/CodeGen/CGCall.cpp b/clang/lib/CodeGen/CGCall.cpp
index 4725dce607eee9..dcf4aa9ac76708 100644
--- a/clang/lib/CodeGen/CGCall.cpp
+++ b/clang/lib/CodeGen/CGCall.cpp
@@ -2465,21 +2465,21 @@ void CodeGenModule::ConstructAttributeList(StringRef Name,
if (TargetDecl->hasAttr<ArmLocallyStreamingAttr>())
FuncAttrs.addAttribute("aarch64_pstate_sm_body");
-
- for (auto Attr : TargetDecl->specific_attrs<attr::LLVMFuncAttr>()) {
+
+ for (auto Attr : TargetDecl->specific_attrs<LLVMFuncAttrAttr>()) {
auto name = Attr->getLLVMAttrName();
auto value = Attr->getLLVMAttrValue();
- Attribute Attr;
+ llvm::Attribute LLAttr;
auto EnumAttr = llvm::Attribute::getAttrKindFromName(name);
if (EnumAttr == llvm::Attribute::None)
- Attr = llvm::Attribute::get(getLLVMContext(), name, value);
+ LLAttr = llvm::Attribute::get(getLLVMContext(), name, value);
else {
assert(value.size() == 0 &&
"enum attribute does not support value yet");
- Attr = llvm::Attribute::get(getLLVMContext(), EnumAttr);
+ LLAttr = llvm::Attribute::get(getLLVMContext(), EnumAttr);
}
- FuncAttrs.addAttribute(Attr);
+ FuncAttrs.addAttribute(LLAttr);
}
}
diff --git a/clang/lib/CodeGen/CodeGenFunction.cpp b/clang/lib/CodeGen/CodeGenFunction.cpp
index 5d0edd4bbf83c7..92abff5915abd0 100644
--- a/clang/lib/CodeGen/CodeGenFunction.cpp
+++ b/clang/lib/CodeGen/CodeGenFunction.cpp
@@ -833,20 +833,20 @@ void CodeGenFunction::StartFunction(GlobalDecl GD, QualType RetTy,
if (D) {
for (auto Attr :
- template TargetDecl->specific_attrs<attr::LLVMFuncAttr>()) {
+ D->template specific_attrs<LLVMFuncAttrAttr>()) {
auto name = Attr->getLLVMAttrName();
auto value = Attr->getLLVMAttrValue();
- Attribute Attr;
+ llvm::Attribute LLAttr;
auto EnumAttr = llvm::Attribute::getAttrKindFromName(name);
if (EnumAttr == llvm::Attribute::None)
- Attr = llvm::Attribute::get(getLLVMContext(), name, value);
+ LLAttr = llvm::Attribute::get(getLLVMContext(), name, value);
else {
assert(value.size() == 0 &&
"enum attribute does not support value yet");
- Attr = llvm::Attribute::get(getLLVMContext(), EnumAttr);
+ LLAttr = llvm::Attribute::get(getLLVMContext(), EnumAttr);
}
- Fn->addFnAttr(Attr);
+ Fn->addFnAttr(LLAttr);
}
}
diff --git a/clang/lib/Sema/SemaDeclAttr.cpp b/clang/lib/Sema/SemaDeclAttr.cpp
index c1c28a73fd79ce..06a1b4317ac0c3 100644
--- a/clang/lib/Sema/SemaDeclAttr.cpp
+++ b/clang/lib/Sema/SemaDeclAttr.cpp
@@ -1689,6 +1689,20 @@ static void handleAllocAlignAttr(Sema &S, Decl *D, const ParsedAttr &AL) {
S.AddAllocAlignAttr(D, AL, AL.getArgAsExpr(0));
}
+static void handleLLVMFuncAttr(Sema &S, Decl *D, const ParsedAttr &AL) {
+ StringRef Name;
+ SourceLocation NameStrLoc;
+ if (!S.checkStringLiteralArgumentAttr(AL, 0, Name, &NameStrLoc))
+ return;
+
+ StringRef Value;
+ SourceLocation ValueStrLoc;
+ if (!S.checkStringLiteralArgumentAttr(AL, 1, Value, &ValueStrLoc))
+ return;
+
+ D->addAttr(::new (S.Context) LLVMFuncAttrAttr(S.Context, AL, Name, Value));
+}
+
void Sema::AddAssumeAlignedAttr(Decl *D, const AttributeCommonInfo &CI, Expr *E,
Expr *OE) {
QualType ResultType = getFunctionOrMethodResultType(D);
@@ -9359,6 +9373,9 @@ ProcessDeclAttribute(Sema &S, Scope *scope, Decl *D, const ParsedAttr &AL,
case ParsedAttr::AT_AllocAlign:
handleAllocAlignAttr(S, D, AL);
break;
+ case ParsedAttr::AT_LLVMFuncAttr:
+ handleLLVMFuncAttr(S, D, AL);
+ break;
case ParsedAttr::AT_Ownership:
handleOwnershipAttr(S, D, AL);
break;
diff --git a/clang/test/CodeGen/attr-llvmfn.c b/clang/test/CodeGen/attr-llvmfn.c
index 72f14a726f795e..14cca30fdfaf85 100644
--- a/clang/test/CodeGen/attr-llvmfn.c
+++ b/clang/test/CodeGen/attr-llvmfn.c
@@ -1,14 +1,15 @@
-// RUN: %clang_cc1 -debug-info-kind=limited -emit-llvm -o - | FileCheck %s
+// RUN: %clang_cc1 -debug-info-kind=limited -emit-llvm -o - %s | FileCheck %s
void t1() __attribute__((llvm_fn_attr("custom_attr", "custom_value"), llvm_fn_attr("second_attr", "second_value")));
+__attribute__((llvm_fn_attr("third_attr", "third_value")))
void t1()
{
}
-void t2();
-
-void t3() {
- t2() ____attribute__((llvm_fn_attr("custom_attr", "custom_value"), llvm_fn_attr("second_attr", "second_value")));
-}
+// CHECK: define dso_local void @t1() #[[t1attrs:[0-9]+]]
+// CHECK: #[[t1attrs]]
+// CHECK-SAME: "custom_attr"="custom_value"
+// CHECK-SAME: "second_attr"="second_value"
+// CHECK-SAME: "third_attr"="third_value"
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