[mips] Support `micromips` attribute

This patch adds support for the `micromips` and `nomicromips` attributes
for MIPS targets.

Differential revision: https://reviews.llvm.org/D33363

llvm-svn: 303546

clang/include/clang/Basic/Attr.td

@@ -1179,6 +1179,12 @@ def MipsInterrupt : InheritableAttr, TargetSpecificAttr<TargetMips> {
   let Documentation = [MipsInterruptDocs];
 }
 
+def MicroMips : InheritableAttr, TargetSpecificAttr<TargetMips> {
+  let Spellings = [GCC<"micromips">];
+  let Subjects = SubjectList<[Function], ErrorDiag>;
+  let Documentation = [MicroMipsDocs];
+}
+
 def Mode : Attr {
   let Spellings = [GCC<"mode">];
   let Subjects = SubjectList<[Var, Enum, TypedefName, Field], ErrorDiag,
@@ -1261,6 +1267,12 @@ def NoMips16 : InheritableAttr, TargetSpecificAttr<TargetMips> {
   let Documentation = [Undocumented];
 }
 
+def NoMicroMips : InheritableAttr, TargetSpecificAttr<TargetMips> {
+  let Spellings = [GCC<"nomicromips">];
+  let Subjects = SubjectList<[Function], ErrorDiag>;
+  let Documentation = [MicroMipsDocs];
+}
+
 // This is not a TargetSpecificAttr so that is silently accepted and
 // ignored on other targets as encouraged by the OpenCL spec.
 //

clang/include/clang/Basic/AttrDocs.td

@@ -1269,6 +1269,19 @@ The semantics are as follows:
   }];
 }
 
+def MicroMipsDocs : Documentation {
+  let Category = DocCatFunction;
+  let Content = [{
+Clang supports the GNU style ``__attribute__((micromips))`` and
+``__attribute__((nomicromips))`` attributes on MIPS targets. These attributes
+may be attached to a function definition and instructs the backend to generate
+or not to generate microMIPS code for that function.
+
+These attributes override the -mmicromips and -mno-micromips options
+on the command line.
+  }];
+}
+
 def AVRInterruptDocs : Documentation {
   let Category = DocCatFunction;
   let Content = [{

clang/lib/CodeGen/TargetInfo.cpp

@@ -6557,6 +6557,11 @@ public:
       Fn->addFnAttr("nomips16");
     }
 
+    if (FD->hasAttr<MicroMipsAttr>())
+      Fn->addFnAttr("micromips");
+    else if (FD->hasAttr<NoMicroMipsAttr>())
+      Fn->addFnAttr("nomicromips");
+
     const MipsInterruptAttr *Attr = FD->getAttr<MipsInterruptAttr>();
     if (!Attr)
       return;

clang/lib/Sema/SemaDeclAttr.cpp

@@ -5935,12 +5935,18 @@ static void ProcessDeclAttribute(Sema &S, Scope *scope, Decl *D,
     handleDLLAttr(S, D, Attr);
     break;
   case AttributeList::AT_Mips16:
-    handleSimpleAttributeWithExclusions<Mips16Attr, MipsInterruptAttr>(S, D,
-                                                                       Attr);
+    handleSimpleAttributeWithExclusions<Mips16Attr, MicroMipsAttr,
+                                        MipsInterruptAttr>(S, D, Attr);
     break;
   case AttributeList::AT_NoMips16:
     handleSimpleAttribute<NoMips16Attr>(S, D, Attr);
     break;
+  case AttributeList::AT_MicroMips:
+    handleSimpleAttributeWithExclusions<MicroMipsAttr, Mips16Attr>(S, D, Attr);
+    break;
+  case AttributeList::AT_NoMicroMips:
+    handleSimpleAttribute<NoMicroMipsAttr>(S, D, Attr);
+    break;
   case AttributeList::AT_AMDGPUFlatWorkGroupSize:
     handleAMDGPUFlatWorkGroupSizeAttr(S, D, Attr);
     break;

clang/test/CodeGen/micromips-attr.c

@@ -0,0 +1,12 @@
+// RUN: %clang_cc1 -triple mips-linux-gnu -emit-llvm  -o  - %s | FileCheck %s
+
+void __attribute__((micromips)) foo (void) {}
+
+// CHECK: define void @foo() [[MICROMIPS:#[0-9]+]]
+
+void __attribute__((nomicromips)) nofoo (void) {}
+
+// CHECK: define void @nofoo() [[NOMICROMIPS:#[0-9]+]]
+
+// CHECK: attributes [[MICROMIPS]] = { noinline nounwind {{.*}} "micromips" {{.*}} }
+// CHECK: attributes [[NOMICROMIPS]]  = { noinline nounwind {{.*}} "nomicromips" {{.*}} }

clang/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 60 attributes:
+// CHECK: #pragma clang attribute supports 62 attributes:
 // CHECK-NEXT: AMDGPUFlatWorkGroupSize (SubjectMatchRule_function)
 // CHECK-NEXT: AMDGPUNumSGPR (SubjectMatchRule_function)
 // CHECK-NEXT: AMDGPUNumVGPR (SubjectMatchRule_function)
@@ -30,8 +30,10 @@
 // CHECK-NEXT: IFunc (SubjectMatchRule_function)
 // CHECK-NEXT: InternalLinkage (SubjectMatchRule_variable, SubjectMatchRule_function, SubjectMatchRule_record)
 // CHECK-NEXT: LTOVisibilityPublic (SubjectMatchRule_record)
+// CHECK-NEXT: MicroMips (SubjectMatchRule_function)
 // CHECK-NEXT: NoDebug (SubjectMatchRule_hasType_functionType, SubjectMatchRule_objc_method, SubjectMatchRule_variable_not_is_parameter)
 // CHECK-NEXT: NoDuplicate (SubjectMatchRule_function)
+// CHECK-NEXT: NoMicroMips (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: NoSplitStack (SubjectMatchRule_function)

clang/test/Sema/attr-micromips.c

@@ -0,0 +1,15 @@
+// RUN: %clang_cc1 -triple mips-linux-gnu -fsyntax-only -verify %s
+
+__attribute__((nomicromips(0))) void foo1();  // expected-error {{'nomicromips' attribute takes no arguments}}
+__attribute__((micromips(1))) void foo2();    // expected-error {{'micromips' attribute takes no arguments}}
+
+__attribute((nomicromips)) int a; // expected-error {{attribute only applies to functions}}
+__attribute((micromips)) int b;   // expected-error {{attribute only applies to functions}}
+
+__attribute__((micromips,mips16)) void foo5();  // expected-error {{'micromips' and 'mips16' attributes are not compatible}} \
+                                                // expected-note {{conflicting attribute is here}}
+__attribute__((mips16,micromips)) void foo6();  // expected-error {{'mips16' and 'micromips' attributes are not compatible}} \
+                                                // expected-note {{conflicting attribute is here}}
+
+__attribute((micromips)) void foo7();
+__attribute((nomicromips)) void foo8();