ahatanak updated this revision to Diff 39702.
ahatanak added a comment.
I ended up making a few more changes based on the feedback on the
not_tail_called attribute:
- Changed wording in docs and added a code example.
- Made changes to detect both (naked,disable_tail_calls) and
(disable_tail_calls,naked) on a function.
- Added test cases that check disable_tail_calls is not on variables and
doesn't take arguments.
http://reviews.llvm.org/D12547
Files:
include/clang/Basic/Attr.td
include/clang/Basic/AttrDocs.td
lib/CodeGen/CGCall.cpp
lib/Sema/SemaDeclAttr.cpp
test/CodeGen/attr-disable-tail-calls.c
test/Sema/disable-tail-calls-attr.c
Index: test/Sema/disable-tail-calls-attr.c
===================================================================
--- /dev/null
+++ test/Sema/disable-tail-calls-attr.c
@@ -0,0 +1,13 @@
+// RUN: %clang_cc1 -fsyntax-only -verify %s
+
+void __attribute__((disable_tail_calls,naked)) foo1(int a) { // expected-error {{'disable_tail_calls' and 'naked' attributes are not compatible}}
+ __asm__("");
+}
+
+void __attribute__((naked,disable_tail_calls)) foo2(int a) { // expected-error {{'naked' and 'disable_tail_calls' attributes are not compatible}}
+ __asm__("");
+}
+
+int g0 __attribute__((disable_tail_calls)); // expected-warning {{'disable_tail_calls' attribute only applies to functions}}
+
+int foo3(int a) __attribute__((disable_tail_calls("abc"))); // expected-error {{'disable_tail_calls' attribute takes no arguments}}
Index: test/CodeGen/attr-disable-tail-calls.c
===================================================================
--- test/CodeGen/attr-disable-tail-calls.c
+++ test/CodeGen/attr-disable-tail-calls.c
@@ -1,11 +1,19 @@
-// RUN: %clang_cc1 -triple x86_64-apple-macosx10.7.0 %s -emit-llvm -mdisable-tail-calls -o - | FileCheck %s -check-prefix=CHECK -check-prefix=DISABLE
-// RUN: %clang_cc1 -triple x86_64-apple-macosx10.7.0 %s -emit-llvm -o - | FileCheck %s -check-prefix=CHECK -check-prefix=ENABLE
+// RUN: %clang_cc1 -triple x86_64-apple-macosx10.7.0 %s -emit-llvm -mdisable-tail-calls -o - | FileCheck %s -check-prefix=DISABLE
+// RUN: %clang_cc1 -triple x86_64-apple-macosx10.7.0 %s -emit-llvm -o - | FileCheck %s -check-prefix=ENABLE
-// CHECK: define i32 @f1() [[ATTR:#[0-9]+]] {
+// DISABLE: define i32 @f1() [[ATTRTRUE:#[0-9]+]] {
+// DISABLE: define i32 @f2() [[ATTRTRUE]] {
+// ENABLE: define i32 @f1() [[ATTRFALSE:#[0-9]+]] {
+// ENABLE: define i32 @f2() [[ATTRTRUE:#[0-9]+]] {
int f1() {
return 0;
}
-// DISABLE: attributes [[ATTR]] = { {{.*}} "disable-tail-calls"="true" {{.*}} }
-// ENABLE: attributes [[ATTR]] = { {{.*}} "disable-tail-calls"="false" {{.*}} }
+int f2() __attribute__((disable_tail_calls)) {
+ return 0;
+}
+
+// DISABLE: attributes [[ATTRTRUE]] = { {{.*}}"disable-tail-calls"="true"{{.*}} }
+// ENABLE: attributes [[ATTRFALSE]] = { {{.*}}"disable-tail-calls"="false"{{.*}} }
+// ENABLE: attributes [[ATTRTRUE]] = { {{.*}}"disable-tail-calls"="true"{{.*}} }
Index: lib/Sema/SemaDeclAttr.cpp
===================================================================
--- lib/Sema/SemaDeclAttr.cpp
+++ lib/Sema/SemaDeclAttr.cpp
@@ -1581,6 +1581,14 @@
Attr.getAttributeSpellingListIndex()));
}
+static void handleNakedAttr(Sema &S, Decl *D, const AttributeList &Attr) {
+ if (checkAttrMutualExclusion<DisableTailCallsAttr>(S, D, Attr))
+ return;
+
+ D->addAttr(::new (S.Context) NakedAttr(Attr.getRange(), S.Context,
+ Attr.getAttributeSpellingListIndex()));
+}
+
static void handleNoReturnAttr(Sema &S, Decl *D, const AttributeList &attr) {
if (hasDeclarator(D)) return;
@@ -1710,6 +1718,15 @@
Attr.getRange(), S.Context, Attr.getAttributeSpellingListIndex()));
}
+static void handleDisableTailCallsAttr(Sema &S, Decl *D,
+ const AttributeList &Attr) {
+ if (checkAttrMutualExclusion<NakedAttr>(S, D, Attr))
+ return;
+
+ D->addAttr(::new (S.Context) DisableTailCallsAttr(
+ Attr.getRange(), S.Context, Attr.getAttributeSpellingListIndex()));
+}
+
static void handleUsedAttr(Sema &S, Decl *D, const AttributeList &Attr) {
if (const VarDecl *VD = dyn_cast<VarDecl>(D)) {
if (VD->hasLocalStorage()) {
@@ -4883,7 +4900,7 @@
handleHotAttr(S, D, Attr);
break;
case AttributeList::AT_Naked:
- handleSimpleAttribute<NakedAttr>(S, D, Attr);
+ handleNakedAttr(S, D, Attr);
break;
case AttributeList::AT_NoReturn:
handleNoReturnAttr(S, D, Attr);
@@ -5006,6 +5023,9 @@
case AttributeList::AT_NotTailCalled:
handleNotTailCalledAttr(S, D, Attr);
break;
+ case AttributeList::AT_DisableTailCalls:
+ handleDisableTailCallsAttr(S, D, Attr);
+ break;
case AttributeList::AT_Used:
handleUsedAttr(S, D, Attr);
break;
Index: lib/CodeGen/CGCall.cpp
===================================================================
--- lib/CodeGen/CGCall.cpp
+++ lib/CodeGen/CGCall.cpp
@@ -1481,8 +1481,12 @@
FuncAttrs.addAttribute("no-frame-pointer-elim-non-leaf");
}
+ bool DisableTailCalls =
+ (TargetDecl && TargetDecl->hasAttr<DisableTailCallsAttr>()) ||
+ CodeGenOpts.DisableTailCalls;
FuncAttrs.addAttribute("disable-tail-calls",
- llvm::toStringRef(CodeGenOpts.DisableTailCalls));
+ llvm::toStringRef(DisableTailCalls));
+
FuncAttrs.addAttribute("less-precise-fpmad",
llvm::toStringRef(CodeGenOpts.LessPreciseFPMAD));
FuncAttrs.addAttribute("no-infs-fp-math",
Index: include/clang/Basic/AttrDocs.td
===================================================================
--- include/clang/Basic/AttrDocs.td
+++ include/clang/Basic/AttrDocs.td
@@ -1669,3 +1669,19 @@
}];
}
+
+def DisableTailCallsDocs : Documentation {
+ let Category = DocCatFunction;
+ let Content = [{
+The ``disable_tail_calls`` attribute instructs the backend to not perform tail call optimization inside the marked function.
+
+For example:
+
+.. code-block:: c++
+
+ int foo(int a) __attribute__((disable_tail_calls)) {
+ return callee(a); // This call is not tail-call optimized.
+ }
+
+ }];
+}
Index: include/clang/Basic/Attr.td
===================================================================
--- include/clang/Basic/Attr.td
+++ include/clang/Basic/Attr.td
@@ -890,6 +890,13 @@
let Documentation = [Undocumented];
}
+def DisableTailCalls : InheritableAttr {
+ let Spellings = [GNU<"disable_tail_calls">,
+ CXX11<"clang", "disable_tail_calls">];
+ let Subjects = SubjectList<[Function, ObjCMethod]>;
+ let Documentation = [DisableTailCallsDocs];
+}
+
def NoAlias : InheritableAttr {
let Spellings = [Declspec<"noalias">];
let Subjects = SubjectList<[Function]>;
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