Revert "[clang][slh] add attribute for speculative load hardening"

until I figure out why the build is failing or timing out

***************************

Summary:
The prior diff had to be reverted because there were two tests
that failed. I updated the two tests in this diff

clang/test/Misc/pragma-attribute-supported-attributes-list.test
clang/test/SemaCXX/attr-speculative-load-hardening.cpp

LLVM IR already has an attribute for speculative_load_hardening. Before
this commit, when a user passed the -mspeculative-load-hardening flag to
Clang, every function would have this attribute added to it. This Clang
attribute will allow users to opt into SLH on a function by function
basis.

This can be applied to functions and Objective C methods.

Reviewers: chandlerc, echristo, kristof.beyls, aaron.ballman

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D54915

This reverts commit a5b3c232d1e3613f23efbc3960f8e23ea70f2a79.
(r347617)

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@347628 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/include/clang/Basic/Attr.td b/include/clang/Basic/Attr.td
index 5b52ba4f64bc370370fd10cffb8afb2cbd0e8e1b..a6be48c234fed482dae01f55c0989fc82d144736 100644 (file)
--- a/include/clang/Basic/Attr.td
+++ b/include/clang/Basic/Attr.td
@@ -3091,9 +3091,3 @@ def AlwaysDestroy : InheritableAttr {
   let Subjects = SubjectList<[Var]>;
   let Documentation = [AlwaysDestroyDocs];
 }
-
-def SpeculativeLoadHardening : InheritableAttr {
-  let Spellings = [Clang<"speculative_load_hardening">];
-  let Subjects = SubjectList<[Function, ObjCMethod], ErrorDiag>;
-  let Documentation = [SpeculativeLoadHardeningDocs];
-}

diff --git a/include/clang/Basic/AttrDocs.td b/include/clang/Basic/AttrDocs.td
index 203ae827195b1494fcfedfdc85517154c8313cb0..e38c557f140f3a591d47dd080b9b54d9d6444670 100644 (file)
--- a/include/clang/Basic/AttrDocs.td
+++ b/include/clang/Basic/AttrDocs.td
@@ -3629,27 +3629,3 @@ GNU inline semantics are the default behavior with ``-std=gnu89``,
 ``-std=c89``, ``-std=c94``, or ``-fgnu89-inline``.
   }];
 }
-
-def SpeculativeLoadHardeningDocs : Documentation {
-  let Category = DocCatFunction;
-  let Content = [{
-  This attribute can be applied to a function declaration in order to indicate
-  that `Speculative Load Hardening <https://llvm.org/docs/SpeculativeLoadHardening.html>`_
-  should be enabled for the function body. This can also be applied to a method
-  in Objective C.
-
-  Speculative Load Hardening is a best-effort mitigation against
-  information leak attacks that make use of control flow
-  miss-speculation - specifically miss-speculation of whether a branch
-  is taken or not. Typically vulnerabilities enabling such attacks are
-  classified as "Spectre variant #1". Notably, this does not attempt to
-  mitigate against miss-speculation of branch target, classified as
-  "Spectre variant #2" vulnerabilities.
-
-  When inlining, the attribute is sticky. Inlining a function that
-  carries this attribute will cause the caller to gain the
-  attribute. This is intended to provide a maximally conservative model
-  where the code in a function annotated with this attribute will always
-  (even after inlining) end up hardened.
-  }];
-}

diff --git a/lib/CodeGen/CGCall.cpp b/lib/CodeGen/CGCall.cpp
index 6d89f3919fd11ee0423a6dfea56ee22d46c10a97..0ec5c7fb45206d2c0bcc30730193092dc12fec2f 100644 (file)
--- a/lib/CodeGen/CGCall.cpp
+++ b/lib/CodeGen/CGCall.cpp
@@ -1791,8 +1791,6 @@ void CodeGenModule::ConstructDefaultFnAttrList(StringRef Name, bool HasOptnone,
     if (CodeGenOpts.Backchain)
       FuncAttrs.addAttribute("backchain");
 
-    // FIXME: The interaction of this attribute with the SLH command line flag
-    // has not been determined.
     if (CodeGenOpts.SpeculativeLoadHardening)
       FuncAttrs.addAttribute(llvm::Attribute::SpeculativeLoadHardening);
   }
@@ -1856,8 +1854,6 @@ void CodeGenModule::ConstructAttributeList(
       FuncAttrs.addAttribute(llvm::Attribute::NoDuplicate);
     if (TargetDecl->hasAttr<ConvergentAttr>())
       FuncAttrs.addAttribute(llvm::Attribute::Convergent);
-    if (TargetDecl->hasAttr<SpeculativeLoadHardeningAttr>())
-      FuncAttrs.addAttribute(llvm::Attribute::SpeculativeLoadHardening);
 
     if (const FunctionDecl *Fn = dyn_cast<FunctionDecl>(TargetDecl)) {
       AddAttributesFromFunctionProtoType(

diff --git a/lib/Sema/SemaDeclAttr.cpp b/lib/Sema/SemaDeclAttr.cpp
index be662b9b914d4b6536b62cf4c51735dce9a22c9c..9f5325d109ebe0d923aaa40a687df3fd4097f04b 100644 (file)
--- a/lib/Sema/SemaDeclAttr.cpp
+++ b/lib/Sema/SemaDeclAttr.cpp
@@ -6373,9 +6373,6 @@ static void ProcessDeclAttribute(Sema &S, Scope *scope, Decl *D,
   case ParsedAttr::AT_Section:
     handleSectionAttr(S, D, AL);
     break;
-  case ParsedAttr::AT_SpeculativeLoadHardening:
-    handleSimpleAttribute<SpeculativeLoadHardeningAttr>(S, D, AL);
-    break;
   case ParsedAttr::AT_CodeSeg:
     handleCodeSegAttr(S, D, AL);
     break;

diff --git a/test/CodeGen/attr-speculative-load-hardening.cpp b/test/CodeGen/attr-speculative-load-hardening.cpp
deleted file mode 100644 (file)
index e2eb805..0000000
--- a/test/CodeGen/attr-speculative-load-hardening.cpp
+++ /dev/null
@@ -1,18 +0,0 @@
-// RUN: %clang_cc1 -std=c++11 -disable-llvm-passes -emit-llvm %s -o - | FileCheck %s --check-prefix=CHECK1
-// RUN: %clang_cc1 -std=c++11 -disable-llvm-passes -emit-llvm %s -o - | FileCheck %s --check-prefix=CHECK2
-//
-// Check that we set the attribute on each function.
-
-[[clang::speculative_load_hardening]]
-int test1() {
-  return 42;
-}
-
-int __attribute__((speculative_load_hardening)) test2() {
-  return 42;
-}
-// CHECK1: @{{.*}}test1{{.*}}[[SLH1:#[0-9]+]]
-// CHECK1: attributes [[SLH1]] = { {{.*}}speculative_load_hardening{{.*}} }
-
-// CHECK2: @{{.*}}test2{{.*}}[[SLH2:#[0-9]+]]
-// CHECK2: attributes [[SLH2]] = { {{.*}}speculative_load_hardening{{.*}} }

diff --git a/test/CodeGen/attr-speculative-load-hardening.m b/test/CodeGen/attr-speculative-load-hardening.m
deleted file mode 100644 (file)
index 2de945b..0000000
--- a/test/CodeGen/attr-speculative-load-hardening.m
+++ /dev/null
@@ -1,9 +0,0 @@
-// RUN: %clang -emit-llvm %s -o - -S | FileCheck %s -check-prefix=SLH
-
-int main() __attribute__((speculative_load_hardening)) {
-  return 0;
-}
-
-// SLH: @{{.*}}main{{.*}}[[SLH:#[0-9]+]]
-
-// SLH: attributes [[SLH]] = { {{.*}}speculative_load_hardening{{.*}} }

diff --git a/test/Misc/pragma-attribute-supported-attributes-list.test b/test/Misc/pragma-attribute-supported-attributes-list.test
index 0aa923de7dfab25a975d23910c90bbe5da72e885..0a54c6c05adae6d793f8340cd8ac40e7c0ccb1b5 100644 (file)
--- a/test/Misc/pragma-attribute-supported-attributes-list.test
+++ b/test/Misc/pragma-attribute-supported-attributes-list.test
@@ -2,7 +2,7 @@
 
 // The number of supported attributes should never go down!
 
-// CHECK: #pragma clang attribute supports 130 attributes:
+// CHECK: #pragma clang attribute supports 129 attributes:
 // CHECK-NEXT: AMDGPUFlatWorkGroupSize (SubjectMatchRule_function)
 // CHECK-NEXT: AMDGPUNumSGPR (SubjectMatchRule_function)
 // CHECK-NEXT: AMDGPUNumVGPR (SubjectMatchRule_function)
@@ -116,7 +116,6 @@
 // CHECK-NEXT: ScopedLockable (SubjectMatchRule_record)
 // CHECK-NEXT: Section (SubjectMatchRule_function, SubjectMatchRule_variable_is_global, SubjectMatchRule_objc_method, SubjectMatchRule_objc_property)
 // CHECK-NEXT: SetTypestate (SubjectMatchRule_function_is_member)
-// CHECK-NEXT: SpeculativeLoadHardening (SubjectMatchRule_function, SubjectMatchRule_objc_method)
 // CHECK-NEXT: SwiftContext (SubjectMatchRule_variable_is_parameter)
 // CHECK-NEXT: SwiftErrorResult (SubjectMatchRule_variable_is_parameter)
 // CHECK-NEXT: SwiftIndirectResult (SubjectMatchRule_variable_is_parameter)

diff --git a/test/SemaCXX/attr-speculative-load-hardening.cpp b/test/SemaCXX/attr-speculative-load-hardening.cpp
deleted file mode 100644 (file)
index bba3b69..0000000
--- a/test/SemaCXX/attr-speculative-load-hardening.cpp
+++ /dev/null
@@ -1,34 +0,0 @@
-// RUN: %clang_cc1 -std=c++11 -fsyntax-only -verify %s
-
-int i __attribute__((speculative_load_hardening)); // expected-error {{'speculative_load_hardening' attribute only applies to functions}}
-
-void f1() __attribute__((speculative_load_hardening));
-void f2() __attribute__((speculative_load_hardening(1))); // expected-error {{'speculative_load_hardening' attribute takes no arguments}}
-
-template <typename T>
-void tf1() __attribute__((speculative_load_hardening));
-
-int f3(int __attribute__((speculative_load_hardening)), int); // expected-error {{'speculative_load_hardening' attribute only applies to functions}}
-
-struct A {
-  int f __attribute__((speculative_load_hardening));  // expected-error {{'speculative_load_hardening' attribute only applies to functions}}
-  void mf1() __attribute__((speculative_load_hardening));
-  static void mf2() __attribute__((speculative_load_hardening));
-};
-
-int ci [[clang::speculative_load_hardening]]; // expected-error {{'speculative_load_hardening' attribute only applies to functions}}
-
-[[clang::speculative_load_hardening]] void cf1();
-[[clang::speculative_load_hardening(1)]] void cf2(); // expected-error {{'speculative_load_hardening' attribute takes no arguments}}
-
-template <typename T>
-[[clang::speculative_load_hardening]]
-void ctf1();
-
-int cf3(int c[[clang::speculative_load_hardening]], int); // expected-error {{'speculative_load_hardening' attribute only applies to functions}}
-
-struct CA {
-  int f [[clang::speculative_load_hardening]];  // expected-error {{'speculative_load_hardening' attribute only applies to functions}}
-  [[clang::speculative_load_hardening]] void mf1();
-  [[clang::speculative_load_hardening]] static void mf2();
-};