Change keep-static-consts to work on static storage duration, not storage class.

[erichkeane]

Summary

To be more in line with what GCC does, switch the condition to be based
on the Static Storage duration instead of the storage class.

[zturner]

Will this work for the following variable?

constexpr int N = 3;

[erichkeane]

In D53718#1276205, @zturner wrote:

Will this work for the following variable?

constexpr int N = 3;

Yep, just confirmed that it does! Adding to the test and will update the review.

[erichkeane]

Add to the test

[erichkeane]

rL345302

lib/CodeGen/CodeGenModule.cpp

void CodeGenModule::SetCommonAttributes(GlobalDecl GD, llvm::GlobalValue *GV) {
   else
     GV->setVisibility(llvm::GlobalValue::DefaultVisibility);
 
   if (D && D->hasAttr<UsedAttr>())
     addUsedGlobal(GV);
 
   if (CodeGenOpts.KeepStaticConsts && D && isa<VarDecl>(D)) {
     const auto *VD = cast<VarDecl>(D);
-    if (VD->getType().isConstQualified() && VD->getStorageClass() == SC_Static)
+    if (VD->getType().isConstQualified() &&
+        VD->getStorageDuration() == SD_Static)
       addUsedGlobal(GV);
   }
 }
 
 bool CodeGenModule::GetCPUAndFeaturesAttributes(const Decl *D,
                                                 llvm::AttrBuilder &Attrs) {
   // Add target-cpu and target-features attributes to functions. If
   // we have a decl for the function and it has a target attribute then

 bool CodeGenModule::MustBeEmitted(const ValueDecl *Global) {
   // Never defer when EmitAllDecls is specified.
   if (LangOpts.EmitAllDecls)
     return true;
 
   if (CodeGenOpts.KeepStaticConsts) {
     const auto *VD = dyn_cast<VarDecl>(Global);
     if (VD && VD->getType().isConstQualified() &&
-        VD->getStorageClass() == SC_Static)
+        VD->getStorageDuration() == SD_Static)
       return true;
   }
 
   return getContext().DeclMustBeEmitted(Global);
 }
 
 bool CodeGenModule::MayBeEmittedEagerly(const ValueDecl *Global) {
   if (const auto *FD = dyn_cast<FunctionDecl>(Global))

test/CodeGen/keep-static-consts.cpp

 // RUN: %clang_cc1 -fkeep-static-consts -emit-llvm %s -o - -triple=x86_64-unknown-linux-gnu | FileCheck %s
 
 // CHECK: @_ZL7srcvers = internal constant [4 x i8] c"xyz\00", align 1
-// CHECK: @llvm.used = appending global [1 x i8*] [i8* getelementptr inbounds ([4 x i8], [4 x i8]* @_ZL7srcvers, i32 0, i32 0)], section "llvm.metadata"
+// CHECK: @_ZL8srcvers2 = internal constant [4 x i8] c"abc\00", align 1
+// CHECK: @_ZL1N = internal constant i32 2, align 4
+// CHECK: @llvm.used = appending global [4 x i8*] [i8* getelementptr inbounds ([4 x i8], [4 x i8]* @_ZL7srcvers, i32 0, i32 0), i8* bitcast (i32* @b to i8*), i8* getelementptr inbounds ([4 x i8], [4 x i8]* @_ZL8srcvers2, i32 0, i32 0), i8* bitcast (i32* @_ZL1N to i8*)], section "llvm.metadata"
+
 static const char srcvers[] = "xyz";
 extern const int b = 1;
+const char srcvers2[] = "abc";
+constexpr int N = 2;