The following patch adds __attribute__((no_address_safety_analysis)) which will allow to disable
address safety analysis (such as e.g. AddressSanitizer or SAFECode) for a specific function.
When building with AddressSanitizer, add AddressSafety function attribute to every generated function
except for those that have __attribute__((no_address_safety_analysis)).
With this patch we will be able to
1. disable AddressSanitizer for a particular function
2. disable AddressSanitizer-hostile optimizations (such as some cases of load widening) when AddressSanitizer is on.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@148842 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/docs/LanguageExtensions.html b/docs/LanguageExtensions.html
index 7b832ba..7693d24 100644
--- a/docs/LanguageExtensions.html
+++ b/docs/LanguageExtensions.html
@@ -1453,6 +1453,10 @@
to check if the code is being built with <a
href="AddressSanitizer.html">AddressSanitizer</a>.
</p>
+<p>Use <tt>__attribute__((no_address_safety_analysis))</tt> on a function
+declaration to specify that address safety instrumentation (e.g.
+AddressSanitizer) should not be applied to that function.
+</p>
<!-- ======================================================================= -->
<h2 id="threadsafety">Thread-Safety Annotation Checking</h2>
diff --git a/include/clang/Basic/Attr.td b/include/clang/Basic/Attr.td
index 292c9a3..a7680bb 100644
--- a/include/clang/Basic/Attr.td
+++ b/include/clang/Basic/Attr.td
@@ -576,6 +576,10 @@
let Spellings = [];
}
+// AddressSafety attribute (e.g. for AddressSanitizer)
+def NoAddressSafetyAnalysis : InheritableAttr {
+ let Spellings = ["no_address_safety_analysis"];
+}
// C/C++ Thread safety attributes (e.g. for deadlock, data race checking)
diff --git a/include/clang/Sema/AttributeList.h b/include/clang/Sema/AttributeList.h
index a54c182..545350f 100644
--- a/include/clang/Sema/AttributeList.h
+++ b/include/clang/Sema/AttributeList.h
@@ -218,6 +218,7 @@
AT_naked,
AT_neon_polyvector_type, // Clang-specific.
AT_neon_vector_type, // Clang-specific.
+ AT_no_address_safety_analysis,
AT_no_instrument_function,
AT_no_thread_safety_analysis,
AT_nocommon,
diff --git a/lib/CodeGen/CodeGenModule.cpp b/lib/CodeGen/CodeGenModule.cpp
index c54b904..6705901 100644
--- a/lib/CodeGen/CodeGenModule.cpp
+++ b/lib/CodeGen/CodeGenModule.cpp
@@ -1019,6 +1019,14 @@
if (ExtraAttrs != llvm::Attribute::None)
F->addFnAttr(ExtraAttrs);
+ if (Features.AddressSanitizer) {
+ // When AddressSanitizer is enabled, set AddressSafety attribute
+ // unless __attribute__((no_address_safety_analysis)) is used.
+ const FunctionDecl *FD = cast_or_null<FunctionDecl>(D.getDecl());
+ if (!FD || !FD->hasAttr<NoAddressSafetyAnalysisAttr>())
+ F->addFnAttr(llvm::Attribute::AddressSafety);
+ }
+
// This is the first use or definition of a mangled name. If there is a
// deferred decl with this name, remember that we need to emit it at the end
// of the file.
diff --git a/lib/Sema/AttributeList.cpp b/lib/Sema/AttributeList.cpp
index c184676..a3791de 100644
--- a/lib/Sema/AttributeList.cpp
+++ b/lib/Sema/AttributeList.cpp
@@ -218,6 +218,7 @@
.Case("pt_guarded_var", AT_pt_guarded_var)
.Case("scoped_lockable", AT_scoped_lockable)
.Case("lockable", AT_lockable)
+ .Case("no_address_safety_analysis", AT_no_address_safety_analysis)
.Case("no_thread_safety_analysis", AT_no_thread_safety_analysis)
.Case("guarded_by", AT_guarded_by)
.Case("pt_guarded_by", AT_pt_guarded_by)
diff --git a/lib/Sema/SemaDeclAttr.cpp b/lib/Sema/SemaDeclAttr.cpp
index e06d637..b15ad0d 100644
--- a/lib/Sema/SemaDeclAttr.cpp
+++ b/lib/Sema/SemaDeclAttr.cpp
@@ -444,6 +444,23 @@
S.Context));
}
+static void handleNoAddressSafetyAttr(Sema &S, Decl *D,
+ const AttributeList &Attr) {
+ assert(!Attr.isInvalid());
+
+ if (!checkAttributeNumArgs(S, Attr, 0))
+ return;
+
+ if (!isa<FunctionDecl>(D) && !isa<FunctionTemplateDecl>(D)) {
+ S.Diag(Attr.getLoc(), diag::warn_attribute_wrong_decl_type)
+ << Attr.getName() << ExpectedFunctionOrMethod;
+ return;
+ }
+
+ D->addAttr(::new (S.Context) NoAddressSafetyAnalysisAttr(Attr.getRange(),
+ S.Context));
+}
+
static void handleAcquireOrderAttr(Sema &S, Decl *D, const AttributeList &Attr,
bool before) {
assert(!Attr.isInvalid());
@@ -3678,6 +3695,9 @@
case AttributeList::AT_scoped_lockable:
handleLockableAttr(S, D, Attr, /*scoped = */true);
break;
+ case AttributeList::AT_no_address_safety_analysis:
+ handleNoAddressSafetyAttr(S, D, Attr);
+ break;
case AttributeList::AT_no_thread_safety_analysis:
handleNoThreadSafetyAttr(S, D, Attr);
break;
diff --git a/test/CodeGen/address-safety-attr.cpp b/test/CodeGen/address-safety-attr.cpp
new file mode 100644
index 0000000..9d0fb95
--- /dev/null
+++ b/test/CodeGen/address-safety-attr.cpp
@@ -0,0 +1,35 @@
+// RUN: %clang_cc1 -emit-llvm -o - %s | FileCheck %s
+// RUN: %clang_cc1 -emit-llvm -o - %s -faddress-sanitizer | FileCheck -check-prefix ASAN %s
+
+// The address_safety attribute should be attached to functions
+// when AddressSanitizer is enabled, unless no_address_safety_analysis attribute
+// is present.
+
+// CHECK-NOT: NoAddressSafety1{{.*}} address_safety
+// ASAN-NOT: NoAddressSafety1{{.*}} address_safety
+__attribute__((no_address_safety_analysis))
+int NoAddressSafety1(int *a) { return *a; }
+
+// CHECK-NOT: NoAddressSafety2{{.*}} address_safety
+// ASAN-NOT: NoAddressSafety2{{.*}} address_safety
+__attribute__((no_address_safety_analysis))
+int NoAddressSafety2(int *a);
+int NoAddressSafety2(int *a) { return *a; }
+
+// CHECK-NOT: AddressSafetyOk{{.*}} address_safety
+// ASAN: AddressSafetyOk{{.*}} address_safety
+int AddressSafetyOk(int *a) { return *a; }
+
+// CHECK-NOT: TemplateNoAddressSafety{{.*}} address_safety
+// ASAN-NOT: TemplateNoAddressSafety{{.*}} address_safety
+template<int i>
+__attribute__((no_address_safety_analysis))
+int TemplateNoAddressSafety() { return i; }
+
+// CHECK-NOT: TemplateAddressSafetyOk{{.*}} address_safety
+// ASAN: TemplateAddressSafetyOk{{.*}} address_safety
+template<int i>
+int TemplateAddressSafetyOk() { return i; }
+
+int force_instance = TemplateAddressSafetyOk<42>()
+ + TemplateNoAddressSafety<42>();