Implement the no_split_stack attribute.

This is a GNU attribute that allows split stacks to be turned off on a
per-function basis.

Differential Revision: http://reviews.llvm.org/D3817

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@209167 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/include/clang/Basic/Attr.td b/include/clang/Basic/Attr.td
index 5c5e597993a1e46b4829c48aefce0a43615274b7..a243994e202ae3c148de980870c900b0e3ed68b0 100644 (file)
--- a/include/clang/Basic/Attr.td
+++ b/include/clang/Basic/Attr.td
@@ -823,6 +823,12 @@ def NoMips16 : InheritableAttr, TargetSpecificAttr<TargetMips> {
   let Documentation = [Undocumented];
 }
 
+def NoSplitStack : InheritableAttr {
+  let Spellings = [GCC<"no_split_stack">];
+  let Subjects = SubjectList<[Function], ErrorDiag>;
+  let Documentation = [NoSplitStackDocs];
+}
+
 def NonNull : InheritableAttr {
   let Spellings = [GCC<"nonnull">];
   let Subjects = SubjectList<[ObjCMethod, HasFunctionProto, ParmVar], WarnDiag,

diff --git a/include/clang/Basic/AttrDocs.td b/include/clang/Basic/AttrDocs.td
index a5eb25c1d9f2dff3639b5b8a3ab44ff49396c6d9..a0c2028512a3d53d6340ff38e761bec50e19a86f 100644 (file)
--- a/include/clang/Basic/AttrDocs.td
+++ b/include/clang/Basic/AttrDocs.td
@@ -371,6 +371,15 @@ of the condition.
   }];
 }
 
+def NoSplitStackDocs : Documentation {
+  let Category = DocCatFunction;
+  let Content = [{
+The ``no_split_stack`` attribute disables the emission of the split stack
+preamble for a particular function. It has no effect if ``-fsplit-stack``
+is not specified.
+  }];
+}
+
 def ObjCRequiresSuperDocs : Documentation {
   let Category = DocCatFunction;
   let Content = [{

diff --git a/lib/CodeGen/CGCall.cpp b/lib/CodeGen/CGCall.cpp
index 61bf985278e566bd02e2bf14dfe1654bf886435b..e477a54c67efeb3dd402551f9e5774fb56c3c889 100644 (file)
--- a/lib/CodeGen/CGCall.cpp
+++ b/lib/CodeGen/CGCall.cpp
@@ -1117,7 +1117,8 @@ void CodeGenModule::ConstructAttributeList(const CGFunctionInfo &FI,
     FuncAttrs.addAttribute(llvm::Attribute::NoRedZone);
   if (CodeGenOpts.NoImplicitFloat)
     FuncAttrs.addAttribute(llvm::Attribute::NoImplicitFloat);
-  if (CodeGenOpts.EnableSegmentedStacks)
+  if (CodeGenOpts.EnableSegmentedStacks &&
+      !(TargetDecl && TargetDecl->hasAttr<NoSplitStackAttr>()))
     FuncAttrs.addAttribute("split-stack");
 
   if (AttrOnCallSite) {

diff --git a/lib/Sema/SemaDeclAttr.cpp b/lib/Sema/SemaDeclAttr.cpp
index 2e97a8aa9d4a89f650676ac4952ff138fcb0c06c..b7c1d5d15b76d46c2e37dcbbced4e4dd7fbfd44d 100644 (file)
--- a/lib/Sema/SemaDeclAttr.cpp
+++ b/lib/Sema/SemaDeclAttr.cpp
@@ -4180,6 +4180,9 @@ static void ProcessDeclAttribute(Sema &S, Scope *scope, Decl *D,
   case AttributeList::AT_NoCommon:
     handleSimpleAttribute<NoCommonAttr>(S, D, Attr);
     break;
+  case AttributeList::AT_NoSplitStack:
+    handleSimpleAttribute<NoSplitStackAttr>(S, D, Attr);
+    break;
   case AttributeList::AT_NonNull:
     if (ParmVarDecl *PVD = dyn_cast<ParmVarDecl>(D))
       handleNonNullAttrParameter(S, PVD, Attr);

diff --git a/test/CodeGen/split-stacks.c b/test/CodeGen/split-stacks.c
index 98112467a56f3144150b807ed6b0880af2c0746d..bf4cf0f026aa01976a08b289f5be2ef84ea4eaf6 100644 (file)
--- a/test/CodeGen/split-stacks.c
+++ b/test/CodeGen/split-stacks.c
@@ -5,13 +5,21 @@ int foo() {
   return 0;
 }
 
+__attribute__((no_split_stack))
+int nosplit() {
+  return 0;
+}
+
 int main() {
   return foo();
 }
 
-// CHECK-SEGSTK: define i32 @foo() #0 {
-// CHECK-SEGSTK: define i32 @main() #0 {
-// CHECK-SEGSTK: #0 = { {{.*}} "split-stack" {{.*}} }
+// CHECK-SEGSTK: define i32 @foo() [[SS:#[0-9]+]] {
+// CHECK-SEGSTK: define i32 @nosplit() [[NSS:#[0-9]+]] {
+// CHECK-SEGSTK: define i32 @main() [[SS]] {
+// CHECK-SEGSTK-NOT: [[NSS]] = { {{.*}} "split-stack" {{.*}} }
+// CHECK-SEGSTK: [[SS]] = { {{.*}} "split-stack" {{.*}} }
+// CHECK-SEGSTK-NOT: [[NSS]] = { {{.*}} "split-stack" {{.*}} }
 
 // CHECK-NOSEGSTK: define i32 @foo() #0 {
 // CHECK-NOSEGSTK: define i32 @main() #0 {

diff --git a/test/CodeGenCXX/split-stacks.cpp b/test/CodeGenCXX/split-stacks.cpp
new file mode 100644 (file)
index 0000000..3e12034
--- /dev/null
+++ b/test/CodeGenCXX/split-stacks.cpp
@@ -0,0 +1,33 @@
+// RUN: %clang -target x86_64-linux-gnu -fsplit-stack -S -std=c++11 %s -emit-llvm -o - | FileCheck -check-prefix=CHECK-SEGSTK %s
+// RUN: %clang -target x86_64-linux-gnu -S -std=c++11 %s -emit-llvm -o - | FileCheck -check-prefix=CHECK-NOSEGSTK %s
+
+int foo() {
+  return 0;
+}
+
+template <typename T>
+[[gnu::no_split_stack]]
+int tnosplit() {
+  return 0;
+}
+
+[[gnu::no_split_stack]]
+int nosplit() {
+  return tnosplit<int>();
+}
+
+// CHECK-SEGSTK: define i32 @_Z3foov() [[SS:#[0-9]+]] {
+// CHECK-SEGSTK: define i32 @_Z7nosplitv() [[NSS1:#[0-9]+]] {
+// CHECK-SEGSTK: define linkonce_odr i32 @_Z8tnosplitIiEiv() [[NSS2:#[0-9]+]] {
+// CHECK-SEGSTK-NOT: [[NSS1]] = { {{.*}} "split-stack" {{.*}} }
+// CHECK-SEGSTK-NOT: [[NSS2]] = { {{.*}} "split-stack" {{.*}} }
+// CHECK-SEGSTK: [[SS]] = { {{.*}} "split-stack" {{.*}} }
+// CHECK-SEGSTK-NOT: [[NSS1]] = { {{.*}} "split-stack" {{.*}} }
+// CHECK-SEGSTK-NOT: [[NSS2]] = { {{.*}} "split-stack" {{.*}} }
+
+// CHECK-NOSEGSTK: define i32 @_Z3foov() [[NSS0:#[0-9]+]] {
+// CHECK-NOSEGSTK: define i32 @_Z7nosplitv() [[NSS1:#[0-9]+]] {
+// CHECK-NOSEGSTK: define linkonce_odr i32 @_Z8tnosplitIiEiv() [[NSS2:#[0-9]+]] {
+// CHECK-NOSEGSTK-NOT: [[NSS1]] = { {{.*}} "split-stack" {{.*}} }
+// CHECK-NOSEGSTK-NOT: [[NSS2]] = { {{.*}} "split-stack" {{.*}} }
+// CHECK-NOSEGSTK-NOT: [[NSS3]] = { {{.*}} "split-stack" {{.*}} }

diff --git a/test/SemaCXX/attr-no-split-stack.cpp b/test/SemaCXX/attr-no-split-stack.cpp
new file mode 100644 (file)
index 0000000..3575e99
--- /dev/null
+++ b/test/SemaCXX/attr-no-split-stack.cpp
@@ -0,0 +1,34 @@
+// RUN: %clang_cc1 -std=c++11 -fsyntax-only -verify %s
+
+int i __attribute__((no_split_stack)); // expected-error {{'no_split_stack' attribute only applies to functions}}
+
+void f1() __attribute__((no_split_stack));
+void f2() __attribute__((no_split_stack(1))); // expected-error {{'no_split_stack' attribute takes no arguments}}
+
+template <typename T>
+void tf1() __attribute__((no_split_stack));
+
+int f3(int __attribute__((no_split_stack)), int); // expected-error{{'no_split_stack' attribute only applies to functions}}
+
+struct A {
+  int f __attribute__((no_split_stack));  // expected-error{{'no_split_stack' attribute only applies to functions}}
+  void mf1() __attribute__((no_split_stack));
+  static void mf2() __attribute__((no_split_stack));
+};
+
+int ci [[gnu::no_split_stack]]; // expected-error {{'no_split_stack' attribute only applies to functions}}
+
+[[gnu::no_split_stack]] void cf1();
+[[gnu::no_split_stack(1)]] void cf2(); // expected-error {{'no_split_stack' attribute takes no arguments}}
+
+template <typename T>
+[[gnu::no_split_stack]]
+void ctf1();
+
+int cf3(int c[[gnu::no_split_stack]], int); // expected-error{{'no_split_stack' attribute only applies to functions}}
+
+struct CA {
+  int f [[gnu::no_split_stack]];  // expected-error{{'no_split_stack' attribute only applies to functions}}
+  [[gnu::no_split_stack]] void mf1();
+  [[gnu::no_split_stack]] static void mf2();
+};