From: Erich Keane <erich.keane@intel.com>
Date: Wed, 14 Feb 2018 00:14:07 +0000 (+0000)
Subject: Implement function attribute artificial
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=789b385fd15c27c91e621faf571e2f6ff060208c;p=clang

Implement function attribute artificial

Added support in clang for GCC function attribute 'artificial'. This attribute
is used to control stepping behavior of debugger with respect to inline
functions.

Patch By: Elizabeth Andrews (eandrews)

Differential Revision: https://reviews.llvm.org/D43259



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@325081 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/include/clang/Basic/Attr.td b/include/clang/Basic/Attr.td
index c3a4d4b058..3e72700d33 100644
--- a/include/clang/Basic/Attr.td
+++ b/include/clang/Basic/Attr.td
@@ -111,6 +111,9 @@ def SharedVar : SubsetSubject<Var,
 def GlobalVar : SubsetSubject<Var,
                              [{S->hasGlobalStorage()}], "global variables">;
 
+def InlineFunction : SubsetSubject<Function,
+                             [{S->isInlineSpecified()}], "inline functions">;
+
 // FIXME: this hack is needed because DeclNodes.td defines the base Decl node
 // type to be a class, not a definition. This makes it impossible to create an
 // attribute subject which accepts a Decl. Normally, this is not a problem,
@@ -588,6 +591,12 @@ def AlwaysInline : InheritableAttr {
   let Documentation = [Undocumented];
 }
 
+def Artificial : InheritableAttr {
+  let Spellings = [GCC<"artificial">];
+  let Subjects = SubjectList<[InlineFunction], WarnDiag>;
+  let Documentation = [ArtificialDocs];
+}
+
 def XRayInstrument : InheritableAttr {
   let Spellings = [Clang<"xray_always_instrument">,
                    Clang<"xray_never_instrument">];
diff --git a/include/clang/Basic/AttrDocs.td b/include/clang/Basic/AttrDocs.td
index fcb716a97c..881c9b6daf 100644
--- a/include/clang/Basic/AttrDocs.td
+++ b/include/clang/Basic/AttrDocs.td
@@ -3273,3 +3273,13 @@ For more information see
 or `msvc documentation <https://docs.microsoft.com/pl-pl/cpp/cpp/selectany>`_.
 }];
 }
+
+def ArtificialDocs : Documentation {
+  let Category = DocCatFunction;
+  let Content = [{
+The ``artificial`` attribute is used with inline functions to treat the inline 
+function as a unit while debugging. For more information see GCC_ documentation.
+
+.. _GCC: https://gcc.gnu.org/onlinedocs/gcc-4.6.4/gcc/Function-Attributes.html
+  }];
+}
diff --git a/lib/CodeGen/CGDebugInfo.cpp b/lib/CodeGen/CGDebugInfo.cpp
index 412570b0d8..bed531eac3 100644
--- a/lib/CodeGen/CGDebugInfo.cpp
+++ b/lib/CodeGen/CGDebugInfo.cpp
@@ -3235,7 +3235,7 @@ void CGDebugInfo::EmitFunctionStart(GlobalDecl GD, SourceLocation Loc,
   if (Name.startswith("\01"))
     Name = Name.substr(1);
 
-  if (!HasDecl || D->isImplicit()) {
+  if (!HasDecl || D->isImplicit() || D->hasAttr<ArtificialAttr>()) {
     Flags |= llvm::DINode::FlagArtificial;
     // Artificial functions should not silently reuse CurLoc.
     CurLoc = SourceLocation();
diff --git a/lib/Sema/SemaDeclAttr.cpp b/lib/Sema/SemaDeclAttr.cpp
index a5eade8a84..cb6b030b71 100644
--- a/lib/Sema/SemaDeclAttr.cpp
+++ b/lib/Sema/SemaDeclAttr.cpp
@@ -6057,6 +6057,9 @@ static void ProcessDeclAttribute(Sema &S, Scope *scope, Decl *D,
   case AttributeList::AT_AlwaysInline:
     handleAlwaysInlineAttr(S, D, Attr);
     break;
+  case AttributeList::AT_Artificial:
+    handleSimpleAttribute<ArtificialAttr>(S, D, Attr);
+    break;
   case AttributeList::AT_AnalyzerNoReturn:
     handleAnalyzerNoReturnAttr(S, D, Attr);
     break;
diff --git a/test/CodeGen/artificial.c b/test/CodeGen/artificial.c
new file mode 100644
index 0000000000..5db6a67194
--- /dev/null
+++ b/test/CodeGen/artificial.c
@@ -0,0 +1,10 @@
+// RUN: %clang_cc1 -triple=x86_64-unknown-linux-gnu -emit-llvm -debug-info-kind=limited %s -o - | FileCheck %s
+
+extern void foo();
+// CHECK: !DISubprogram(name: "foo"
+// CHECK-SAME: flags: DIFlagArtificial
+inline void __attribute__((artificial)) foo() {}
+
+void baz() {
+  foo();
+}
diff --git a/test/Sema/artificial.c b/test/Sema/artificial.c
new file mode 100644
index 0000000000..076a61ca0f
--- /dev/null
+++ b/test/Sema/artificial.c
@@ -0,0 +1,4 @@
+// RUN: %clang_cc1 -fsyntax-only -verify %s
+
+inline void __attribute__((artificial)) foo() {}
+void __attribute__((artificial)) bar() {} // expected-warning {{'artificial' attribute only applies to inline functions}}