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" <g...@wsmoses.com>
Date: Mon, 26 Feb 2024 16:17:55 -0500
Subject: [PATCH] [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")));
+}
+
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