map previously ignored __attribute((malloc)) to noalias attribute of llvm function's return

llvm-svn: 78541

5 files changed, 22 insertions, 1 deletions

diff --git a/clang/lib/CodeGen/CGCall.cpp b/clang/lib/CodeGen/CGCall.cpp
index 12d4d9ca252..24d82747a40 100644
--- a/clang/lib/CodeGen/CGCall.cpp
+++ b/clang/lib/CodeGen/CGCall.cpp
@@ -385,6 +385,8 @@ void CodeGenModule::ConstructAttributeList(const CGFunctionInfo &FI,
       FuncAttrs |= llvm::Attribute::ReadNone;
     else if (TargetDecl->hasAttr<PureAttr>())
       FuncAttrs |= llvm::Attribute::ReadOnly;
+    if (TargetDecl->hasAttr<MallocAttr>())
+      RetAttrs |= llvm::Attribute::NoAlias;
   }
 
   if (CompileOpts.DisableRedZone)
diff --git a/clang/lib/Frontend/PCHReaderDecl.cpp b/clang/lib/Frontend/PCHReaderDecl.cpp
index 95163af1111..32a1e384cc7 100644
--- a/clang/lib/Frontend/PCHReaderDecl.cpp
+++ b/clang/lib/Frontend/PCHReaderDecl.cpp
@@ -480,6 +480,7 @@ Attr *PCHReader::ReadAttributes() {
       New = ::new (*Context) IBOutletAttr();
       break;
 
+    SIMPLE_ATTR(Malloc);
     SIMPLE_ATTR(NoReturn);
     SIMPLE_ATTR(NoThrow);
     SIMPLE_ATTR(Nodebug);
diff --git a/clang/lib/Frontend/PCHWriter.cpp b/clang/lib/Frontend/PCHWriter.cpp
index 0e570a61abb..d9c6b1bb7d8 100644
--- a/clang/lib/Frontend/PCHWriter.cpp
+++ b/clang/lib/Frontend/PCHWriter.cpp
@@ -1678,6 +1678,7 @@ void PCHWriter::WriteAttributeRecord(const Attr *Attr) {
         
     case Attr::GNUInline:
     case Attr::IBOutletKind:
+    case Attr::Malloc:
     case Attr::NoReturn:
     case Attr::NoThrow:
     case Attr::Nodebug:
diff --git a/clang/lib/Parse/AttributeList.cpp b/clang/lib/Parse/AttributeList.cpp
index 5ee668a3172..32ffba36dd6 100644
--- a/clang/lib/Parse/AttributeList.cpp
+++ b/clang/lib/Parse/AttributeList.cpp
@@ -69,7 +69,7 @@ AttributeList::Kind AttributeList::getKind(const IdentifierInfo *Name) {
     break;
   case 6:
     if (!memcmp(Str, "packed", 6)) return AT_packed;
-    if (!memcmp(Str, "malloc", 6)) return IgnoredAttribute; // FIXME: noalias.
+    if (!memcmp(Str, "malloc", 6)) return AT_malloc;
     if (!memcmp(Str, "format", 6)) return AT_format;
     if (!memcmp(Str, "unused", 6)) return AT_unused;
     if (!memcmp(Str, "blocks", 6)) return AT_blocks;
diff --git a/clang/lib/Sema/SemaDeclAttr.cpp b/clang/lib/Sema/SemaDeclAttr.cpp
index 6df81207861..2f86fe1ffe7 100644
--- a/clang/lib/Sema/SemaDeclAttr.cpp
+++ b/clang/lib/Sema/SemaDeclAttr.cpp
@@ -424,6 +424,22 @@ static void HandleAlwaysInlineAttr(Decl *d, const AttributeList &Attr,
   d->addAttr(::new (S.Context) AlwaysInlineAttr());
 }
 
+static void HandleMallocAttr(Decl *d, const AttributeList &Attr, Sema &S) {
+  // check the attribute arguments.
+  if (Attr.getNumArgs() != 0) {
+    S.Diag(Attr.getLoc(), diag::err_attribute_wrong_number_arguments) << 0;
+    return;
+  }
+
+  if (!isFunctionOrMethod(d)) {
+    S.Diag(Attr.getLoc(), diag::warn_attribute_wrong_decl_type)
+      << Attr.getName() << 0 /*function*/;
+    return;
+  }
+
+  d->addAttr(::new (S.Context) MallocAttr());
+}
+
 static bool HandleCommonNoReturnAttr(Decl *d, const AttributeList &Attr,
                                      Sema &S) {
   // check the attribute arguments.
@@ -1759,6 +1775,7 @@ static void ProcessDeclAttribute(Scope *scope, Decl *D,
   case AttributeList::AT_format_arg:  HandleFormatArgAttr (D, Attr, S); break;
   case AttributeList::AT_gnu_inline:  HandleGNUInlineAttr(D, Attr, S); break;
   case AttributeList::AT_mode:        HandleModeAttr      (D, Attr, S); break;
+  case AttributeList::AT_malloc:      HandleMallocAttr    (D, Attr, S); break;
   case AttributeList::AT_nonnull:     HandleNonNullAttr   (D, Attr, S); break;
   case AttributeList::AT_noreturn:    HandleNoReturnAttr  (D, Attr, S); break;
   case AttributeList::AT_nothrow:     HandleNothrowAttr   (D, Attr, S); break;