[clang][slh] add Clang attr no_speculative_load_hardening

Summary:
This attribute will allow users to opt specific functions out of
speculative load hardening. This compliments the Clang attribute
named speculative_load_hardening. When this attribute or the attribute
speculative_load_hardening is used in combination with the flags
-mno-speculative-load-hardening or -mspeculative-load-hardening,
the function level attribute will override the default during LLVM IR
generation. For example, in the case, where the flag opposes the
function attribute, the function attribute will take precendence.
The sticky inlining behavior of the speculative_load_hardening attribute
may cause a function with the no_speculative_load_hardening attribute
to be tagged with the speculative_load_hardening tag in
subsequent compiler phases which is desired behavior since the
speculative_load_hardening LLVM attribute is designed to be maximally
conservative.

If both attributes are specified for a function, then an error will be
thrown.

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

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D54909

llvm-svn: 351565

6 files changed, 127 insertions, 19 deletions

diff --git a/clang/test/CodeGen/attr-speculative-load-hardening.cpp b/clang/test/CodeGen/attr-speculative-load-hardening.cpp
deleted file mode 100644
index e2eb805cbb8..00000000000
--- a/clang/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/clang/test/CodeGenCXX/attr-speculative-load-hardening.cpp b/clang/test/CodeGenCXX/attr-speculative-load-hardening.cpp
new file mode 100644
index 00000000000..22c5dd52e6b
--- /dev/null
+++ b/clang/test/CodeGenCXX/attr-speculative-load-hardening.cpp
@@ -0,0 +1,62 @@
+// Check that we correctly set or did not set the attribute for each function.
+// 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 correctly set or did not set the attribute on each function despite the
+// -mspeculative-load-hardening flag.
+// RUN: %clang_cc1 -mspeculative-load-hardening -std=c++11 -disable-llvm-passes -emit-llvm %s -o - | FileCheck %s --check-prefix=CHECK3
+// RUN: %clang_cc1 -mspeculative-load-hardening -std=c++11 -disable-llvm-passes -emit-llvm %s -o - | FileCheck %s --check-prefix=CHECK4
+
+
+// Check that we correctly set or did not set the attribute on each function despite the
+// -mno-speculative-load-hardening flag.
+// RUN: %clang -mno-speculative-load-hardening -S -std=c++11 -disable-llvm-passes -emit-llvm %s -o - | FileCheck %s --check-prefix=CHECK5
+// RUN: %clang -mno-speculative-load-hardening -S -std=c++11 -disable-llvm-passes -emit-llvm %s -o - | FileCheck %s --check-prefix=CHECK6
+
+
+[[clang::speculative_load_hardening]]
+int test1() {
+  return 42;
+}
+
+int __attribute__((speculative_load_hardening)) test2() {
+  return 42;
+}
+
+[[clang::no_speculative_load_hardening]]
+int test3() {
+  return 42;
+}
+
+int __attribute__((no_speculative_load_hardening)) test4() {
+  return 42;
+}
+// CHECK1: @{{.*}}test1{{.*}}[[SLH:#[0-9]+]]
+// CHECK1: @{{.*}}test3{{.*}}[[NOSLH:#[0-9]+]]
+// CHECK1: attributes [[SLH]] = { {{.*}}speculative_load_hardening{{.*}} }
+// CHECK1-NOT: attributes [[NOSLH]] = { {{.*}}speculative_load_hardening{{.*}} }
+
+// CHECK2: @{{.*}}test2{{.*}}[[SLH:#[0-9]+]]
+// CHECK2: @{{.*}}test4{{.*}}[[NOSLH:#[0-9]+]]
+// CHECK2: attributes [[SLH]] = { {{.*}}speculative_load_hardening{{.*}} }
+// CHECK2-NOT: attributes [[NOSLH]] = { {{.*}}speculative_load_hardening{{.*}} }
+
+// CHECK3: @{{.*}}test1{{.*}}[[SLH:#[0-9]+]]
+// CHECK3: @{{.*}}test3{{.*}}[[NOSLH:#[0-9]+]]
+// CHECK3: attributes [[SLH]] = { {{.*}}speculative_load_hardening{{.*}} }
+// CHECK3-NOT: attributes [[NOSLH]] = { {{.*}}speculative_load_hardening{{.*}} }
+
+// CHECK4: @{{.*}}test2{{.*}}[[SLH:#[0-9]+]]
+// CHECK4: @{{.*}}test4{{.*}}[[NOSLH:#[0-9]+]]
+// CHECK4: attributes [[SLH]] = { {{.*}}speculative_load_hardening{{.*}} }
+// CHECK4-NOT: attributes [[NOSLH]] = { {{.*}}speculative_load_hardening{{.*}} }
+
+// CHECK5: @{{.*}}test1{{.*}}[[SLH:#[0-9]+]]
+// CHECK5: @{{.*}}test3{{.*}}[[NOSLH:#[0-9]+]]
+// CHECK5: attributes [[SLH]] = { {{.*}}speculative_load_hardening{{.*}} }
+// CHECK5-NOT: attributes [[NOSLH]] = { {{.*}}speculative_load_hardening{{.*}} }
+
+// CHECK6: @{{.*}}test2{{.*}}[[SLH:#[0-9]+]]
+// CHECK6: @{{.*}}test4{{.*}}[[NOSLH:#[0-9]+]]
+// CHECK6: attributes [[SLH]] = { {{.*}}speculative_load_hardening{{.*}} }
+// CHECK6-NOT: attributes [[NOSLH]] = { {{.*}}speculative_load_hardening{{.*}} }
diff --git a/clang/test/CodeGen/attr-speculative-load-hardening.m b/clang/test/CodeGenObjC/attr-speculative-load-hardening.m
index 2de945b974f..3b4929d9356 100644
--- a/clang/test/CodeGen/attr-speculative-load-hardening.m
+++ b/clang/test/CodeGenObjC/attr-speculative-load-hardening.m
@@ -4,6 +4,11 @@ int main() __attribute__((speculative_load_hardening)) {
   return 0;
 }
 
-// SLH: @{{.*}}main{{.*}}[[SLH:#[0-9]+]]
+int test() __attribute__((no_speculative_load_hardening)) {
+  return 0;
+}
 
+// SLH: @{{.*}}main{{.*}}[[SLH:#[0-9]+]]
+// SLH: @{{.*}}test{{.*}}[[NOSLH:#[0-9]+]]
 // SLH: attributes [[SLH]] = { {{.*}}speculative_load_hardening{{.*}} }
+// SLH-NOT: attributes [[NOSLH]] = { {{.*}}speculative_load_hardening{{.*}} }
diff --git a/clang/test/Misc/pragma-attribute-supported-attributes-list.test b/clang/test/Misc/pragma-attribute-supported-attributes-list.test
index 9a6bcca1bd3..9dec259f4fc 100644
--- a/clang/test/Misc/pragma-attribute-supported-attributes-list.test
+++ b/clang/test/Misc/pragma-attribute-supported-attributes-list.test
@@ -80,6 +80,7 @@
 // CHECK-NEXT: NoMips16 (SubjectMatchRule_function)
 // CHECK-NEXT: NoSanitize (SubjectMatchRule_function, SubjectMatchRule_objc_method, SubjectMatchRule_variable_is_global)
 // CHECK-NEXT: NoSanitizeSpecific (SubjectMatchRule_function, SubjectMatchRule_variable_is_global)
+// CHECK-NEXT: NoSpeculativeLoadHardening (SubjectMatchRule_function, SubjectMatchRule_objc_method)
 // CHECK-NEXT: NoSplitStack (SubjectMatchRule_function)
 // CHECK-NEXT: NoStackProtector (SubjectMatchRule_function)
 // CHECK-NEXT: NoThreadSafetyAnalysis (SubjectMatchRule_function)
diff --git a/clang/test/SemaCXX/attr-no-speculative-load-hardening.cpp b/clang/test/SemaCXX/attr-no-speculative-load-hardening.cpp
new file mode 100644
index 00000000000..eebc5278f2f
--- /dev/null
+++ b/clang/test/SemaCXX/attr-no-speculative-load-hardening.cpp
@@ -0,0 +1,34 @@
+// RUN: %clang_cc1 -std=c++11 -fsyntax-only -verify %s
+
+int i __attribute__((no_speculative_load_hardening)); // expected-error {{'no_speculative_load_hardening' attribute only applies to functions}}
+
+void f1() __attribute__((no_speculative_load_hardening));
+void f2() __attribute__((no_speculative_load_hardening(1))); // expected-error {{'no_speculative_load_hardening' attribute takes no arguments}}
+
+template <typename T>
+void tf1() __attribute__((no_speculative_load_hardening));
+
+int f3(int __attribute__((no_speculative_load_hardening)), int); // expected-error {{'no_speculative_load_hardening' attribute only applies to functions}}
+
+struct A {
+  int f __attribute__((no_speculative_load_hardening));  // expected-error {{'no_speculative_load_hardening' attribute only applies to functions}}
+  void mf1() __attribute__((no_speculative_load_hardening));
+  static void mf2() __attribute__((no_speculative_load_hardening));
+};
+
+int ci [[clang::no_speculative_load_hardening]]; // expected-error {{'no_speculative_load_hardening' attribute only applies to functions}}
+
+[[clang::no_speculative_load_hardening]] void cf1();
+[[clang::no_speculative_load_hardening(1)]] void cf2(); // expected-error {{'no_speculative_load_hardening' attribute takes no arguments}}
+
+template <typename T>
+[[clang::no_speculative_load_hardening]]
+void ctf1();
+
+int cf3(int c[[clang::no_speculative_load_hardening]], int); // expected-error {{'no_speculative_load_hardening' attribute only applies to functions}}
+
+struct CA {
+  int f [[clang::no_speculative_load_hardening]];  // expected-error {{'no_speculative_load_hardening' attribute only applies to functions}}
+  [[clang::no_speculative_load_hardening]] void mf1();
+  [[clang::no_speculative_load_hardening]] static void mf2();
+};
diff --git a/clang/test/SemaCXX/attr-speculative-load-hardening.cpp b/clang/test/SemaCXX/attr-speculative-load-hardening.cpp
index bba3b6921e8..ff31e4be179 100644
--- a/clang/test/SemaCXX/attr-speculative-load-hardening.cpp
+++ b/clang/test/SemaCXX/attr-speculative-load-hardening.cpp
@@ -16,6 +16,17 @@ struct A {
   static void mf2() __attribute__((speculative_load_hardening));
 };
 
+void f4() __attribute__((no_speculative_load_hardening, speculative_load_hardening)); // expected-error {{attributes are not compatible}}
+// expected-note@-1 {{conflicting attribute is here}}
+
+void f5() __attribute__((speculative_load_hardening, no_speculative_load_hardening)); // expected-error {{attributes are not compatible}}
+// expected-note@-1 {{conflicting attribute is here}}
+
+void f6() __attribute__((no_speculative_load_hardening));
+
+void f6() __attribute__((speculative_load_hardening)); // expected-error@-2 {{'no_speculative_load_hardening' and 'speculative_load_hardening' attributes are not compatible}}
+// expected-note@-1 {{conflicting attribute is here}}
+
 int ci [[clang::speculative_load_hardening]]; // expected-error {{'speculative_load_hardening' attribute only applies to functions}}
 
 [[clang::speculative_load_hardening]] void cf1();
@@ -32,3 +43,16 @@ struct CA {
   [[clang::speculative_load_hardening]] void mf1();
   [[clang::speculative_load_hardening]] static void mf2();
 };
+
+[[clang::speculative_load_hardening, clang::no_speculative_load_hardening]] void cf4();  // expected-error {{attributes are not compatible}}
+// expected-note@-1 {{conflicting attribute is here}}
+
+[[clang::no_speculative_load_hardening, clang::speculative_load_hardening]] void cf5();  // expected-error {{attributes are not compatible}}
+// expected-note@-1 {{conflicting attribute is here}}
+
+[[clang::speculative_load_hardening]]
+void cf6();
+
+[[clang::no_speculative_load_hardening]]
+void cf6(); // expected-error@-4 {{'speculative_load_hardening' and 'no_speculative_load_hardening' attributes are not compatible}} \
+// expected-note@-1 {{conflicting attribute is here}}