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.

llvm-svn: 148842

3 files changed, 29 insertions, 0 deletions

diff --git a/clang/lib/CodeGen/CodeGenModule.cpp b/clang/lib/CodeGen/CodeGenModule.cpp
index c54b904abcb..67059016f7d 100644
--- a/clang/lib/CodeGen/CodeGenModule.cpp
+++ b/clang/lib/CodeGen/CodeGenModule.cpp
@@ -1019,6 +1019,14 @@ CodeGenModule::GetOrCreateLLVMFunction(StringRef MangledName,
   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/clang/lib/Sema/AttributeList.cpp b/clang/lib/Sema/AttributeList.cpp
index c184676b9e5..a3791dedf73 100644
--- a/clang/lib/Sema/AttributeList.cpp
+++ b/clang/lib/Sema/AttributeList.cpp
@@ -218,6 +218,7 @@ AttributeList::Kind AttributeList::getKind(const IdentifierInfo *Name) {
     .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/clang/lib/Sema/SemaDeclAttr.cpp b/clang/lib/Sema/SemaDeclAttr.cpp
index e06d637eeb7..b15ad0ddd15 100644
--- a/clang/lib/Sema/SemaDeclAttr.cpp
+++ b/clang/lib/Sema/SemaDeclAttr.cpp
@@ -444,6 +444,23 @@ static void handleNoThreadSafetyAttr(Sema &S, Decl *D,
                                                           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 @@ static void ProcessInheritableDeclAttr(Sema &S, Scope *scope, Decl *D,
   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;