Move target MV resolver to COMDAT

[erichkeane]

Summary

As reported here: https://bugs.llvm.org/show_bug.cgi?id=35921
The resolver functions should be in their own
COMDAT regions. This patch sets that up.

[echristo]

Seems reasonable.

lib/CodeGen/CodeGenModule.cpp

getContext().forEachMultiversionedFunctionVersion(
             assert(Func && "This should have just been created");
           }
           Options.emplace_back(getTarget(), cast<llvm::Function>(Func),
                                CurFD->getAttr<TargetAttr>()->parse());
         });
 
     llvm::Function *ResolverFunc = cast<llvm::Function>(
         GetGlobalValue((getMangledName(GD) + ".resolver").str()));
+    if (supportsCOMDAT())
+      ResolverFunc->setComdat(
+          getModule().getOrInsertComdat(ResolverFunc->getName()));
     std::stable_sort(
         Options.begin(), Options.end(),
         std::greater<CodeGenFunction::MultiVersionResolverOption>());
     CodeGenFunction CGF(*this);
     CGF.EmitMultiVersionResolver(ResolverFunc, Options);
   }
 }
 

test/CodeGen/attr-target-mv-va-args.c

 // CHECK: ret i32 0
 // CHECK: define i32 @foo.arch_ivybridge(i32 %i, ...)
 // CHECK: ret i32 1
 // CHECK: define i32 @foo(i32 %i, ...)
 // CHECK: ret i32 2
 // CHECK: define i32 @bar()
 // CHECK: call i32 (i32, ...) @foo.ifunc(i32 1, i32 97, double
 // CHECK: call i32 (i32, ...) @foo.ifunc(i32 2, double 2.2{{[0-9Ee+]+}}, i8* getelementptr inbounds 
-// CHECK: define i32 (i32, ...)* @foo.resolver()
+// CHECK: define i32 (i32, ...)* @foo.resolver() comdat
 // CHECK: ret i32 (i32, ...)* @foo.arch_sandybridge
 // CHECK: ret i32 (i32, ...)* @foo.arch_ivybridge
 // CHECK: ret i32 (i32, ...)* @foo.sse4.2
 // CHECK: ret i32 (i32, ...)* @foo
 // CHECK: declare i32 @foo.arch_sandybridge(i32, ...)

test/CodeGen/attr-target-mv.c

 // CHECK: ret i32 0
 // CHECK: define i32 @foo.arch_ivybridge()
 // CHECK: ret i32 1
 // CHECK: define i32 @foo()
 // CHECK: ret i32 2
 // CHECK: define i32 @bar()
 // CHECK: call i32 @foo.ifunc()
 
-// CHECK: define i32 ()* @foo.resolver()
+// CHECK: define i32 ()* @foo.resolver() comdat
 // CHECK: call void @__cpu_indicator_init()
 // CHECK: ret i32 ()* @foo.arch_sandybridge
 // CHECK: ret i32 ()* @foo.arch_ivybridge
 // CHECK: ret i32 ()* @foo.sse4.2
 // CHECK: ret i32 ()* @foo
 
 // CHECK: define i32 @bar2()
 // CHECK: call i32 @foo_inline.ifunc()
 
-// CHECK: define i32 ()* @foo_inline.resolver()
+// CHECK: define i32 ()* @foo_inline.resolver() comdat
 // CHECK: call void @__cpu_indicator_init()
 // CHECK: ret i32 ()* @foo_inline.arch_sandybridge
 // CHECK: ret i32 ()* @foo_inline.arch_ivybridge
 // CHECK: ret i32 ()* @foo_inline.sse4.2
 // CHECK: ret i32 ()* @foo_inline
 
 // CHECK: define void @bar3()
 // CHECK: call void @foo_decls.ifunc()
 
-// CHECK: define void ()* @foo_decls.resolver()
+// CHECK: define void ()* @foo_decls.resolver() comdat
 // CHECK: ret void ()* @foo_decls.sse4.2
 // CHECK: ret void ()* @foo_decls
 
 // CHECK: declare i32 @foo.arch_sandybridge()
 
 // CHECK: define available_externally i32 @foo_inline.sse4.2()
 // CHECK: ret i32 0
 

test/CodeGenCXX/attr-target-mv-diff-ns.cpp

 // CHECK: ret i32 1
 // CHECK: define i32 @_ZN2ns3fooEi(i32)
 // CHECK: ret i32 2
 
 // CHECK: define i32 @_Z3barv()
 // CHECK: call i32 @_Z3fooi.ifunc(i32 1)
 // CHECK: call i32 @_ZN2ns3fooEi.ifunc(i32 2)
 
-// CHECK: define i32 (i32)* @_Z3fooi.resolver()
+// CHECK: define i32 (i32)* @_Z3fooi.resolver() comdat
 // CHECK: ret i32 (i32)* @_Z3fooi.arch_sandybridge
 // CHECK: ret i32 (i32)* @_Z3fooi.arch_ivybridge
 // CHECK: ret i32 (i32)* @_Z3fooi.sse4.2
 // CHECK: ret i32 (i32)* @_Z3fooi
 //
-// CHECK: define i32 (i32)* @_ZN2ns3fooEi.resolver()
+// CHECK: define i32 (i32)* @_ZN2ns3fooEi.resolver() comdat
 // CHECK: ret i32 (i32)* @_ZN2ns3fooEi.arch_sandybridge
 // CHECK: ret i32 (i32)* @_ZN2ns3fooEi.arch_ivybridge
 // CHECK: ret i32 (i32)* @_ZN2ns3fooEi.sse4.2
 // CHECK: ret i32 (i32)* @_ZN2ns3fooEi
 
 // CHECK: declare i32 @_Z3fooi.arch_sandybridge(i32)
 // CHECK: declare i32 @_ZN2ns3fooEi.arch_sandybridge(i32)

test/CodeGenCXX/attr-target-mv-member-funcs.cpp

 // CHECK: %s = alloca %struct.S, align 1
 // CHECK: %s2 = alloca %struct.S, align 1
 // CHECK: %C = alloca %struct.ConvertTo, align 1
 // CHECK: call dereferenceable(1) %struct.S* @_ZN1SaSERKS_.ifunc(%struct.S* %s2
 // CHECK: call void @_ZNK9ConvertTocv1SEv.ifunc(%struct.ConvertTo* %C)
 // CHECK: call dereferenceable(1) %struct.S* @_ZN1SaSERKS_.ifunc(%struct.S* %s2
 // CHECK: call i32 @_ZN1S3fooEi.ifunc(%struct.S* %s, i32 0)
 
-// CHECK: define %struct.S* (%struct.S*, %struct.S*)* @_ZN1SaSERKS_.resolver()
+// CHECK: define %struct.S* (%struct.S*, %struct.S*)* @_ZN1SaSERKS_.resolver() comdat
 // CHECK: ret %struct.S* (%struct.S*, %struct.S*)* @_ZN1SaSERKS_.arch_ivybridge
 // CHECK: ret %struct.S* (%struct.S*, %struct.S*)* @_ZN1SaSERKS_
 
-// CHECK: define void (%struct.ConvertTo*)* @_ZNK9ConvertTocv1SEv.resolver()
+// CHECK: define void (%struct.ConvertTo*)* @_ZNK9ConvertTocv1SEv.resolver() comdat
 // CHECK: ret void (%struct.ConvertTo*)* @_ZNK9ConvertTocv1SEv.arch_ivybridge
 // CHECK: ret void (%struct.ConvertTo*)* @_ZNK9ConvertTocv1SEv
 
-// CHECK: define i32 (%struct.S*, i32)* @_ZN1S3fooEi.resolver()
+// CHECK: define i32 (%struct.S*, i32)* @_ZN1S3fooEi.resolver() comdat 
 // CHECK: ret i32 (%struct.S*, i32)* @_ZN1S3fooEi.arch_sandybridge
 // CHECK: ret i32 (%struct.S*, i32)* @_ZN1S3fooEi.arch_ivybridge
 // CHECK: ret i32 (%struct.S*, i32)* @_ZN1S3fooEi.sse4.2
 // CHECK: ret i32 (%struct.S*, i32)* @_ZN1S3fooEi
 
 // CHECK: define i32 @_Z4bar2v()
 // CHECK:call i32 @_ZN2S23fooEi.ifunc
-// define i32 (%struct.S2*, i32)* @_ZN2S23fooEi.resolver()
+// define i32 (%struct.S2*, i32)* @_ZN2S23fooEi.resolver() comdat
 // CHECK: ret i32 (%struct.S2*, i32)* @_ZN2S23fooEi.arch_sandybridge
 // CHECK: ret i32 (%struct.S2*, i32)* @_ZN2S23fooEi.arch_ivybridge
 // CHECK: ret i32 (%struct.S2*, i32)* @_ZN2S23fooEi.sse4.2
 // CHECK: ret i32 (%struct.S2*, i32)* @_ZN2S23fooEi
 
 // CHECK: define i32 @_ZN2S23fooEi.sse4.2(%struct.S2* %this, i32)
 // CHECK: define i32 @_ZN2S23fooEi.arch_ivybridge(%struct.S2* %this, i32)
 // CHECK: define i32 @_ZN2S23fooEi(%struct.S2* %this, i32)
 
 // CHECK: define i32 @_Z9templ_usev()
 // CHECK:  call i32 @_ZN5templIiE3fooEi.ifunc
 // CHECK:  call i32 @_ZN5templIdE3fooEi.ifunc
 
 
-// CHECK: define i32 (%struct.templ*, i32)* @_ZN5templIiE3fooEi.resolver()
+// CHECK: define i32 (%struct.templ*, i32)* @_ZN5templIiE3fooEi.resolver() comdat
 // CHECK: ret i32 (%struct.templ*, i32)* @_ZN5templIiE3fooEi.arch_sandybridge
 // CHECK: ret i32 (%struct.templ*, i32)* @_ZN5templIiE3fooEi.arch_ivybridge
 // CHECK: ret i32 (%struct.templ*, i32)* @_ZN5templIiE3fooEi.sse4.2
 // CHECK: ret i32 (%struct.templ*, i32)* @_ZN5templIiE3fooEi
 //
-// CHECK: define i32 (%struct.templ.0*, i32)* @_ZN5templIdE3fooEi.resolver()
+// CHECK: define i32 (%struct.templ.0*, i32)* @_ZN5templIdE3fooEi.resolver() comdat
 // CHECK: ret i32 (%struct.templ.0*, i32)* @_ZN5templIdE3fooEi.arch_sandybridge
 // CHECK: ret i32 (%struct.templ.0*, i32)* @_ZN5templIdE3fooEi.arch_ivybridge
 // CHECK: ret i32 (%struct.templ.0*, i32)* @_ZN5templIdE3fooEi.sse4.2
 // CHECK: ret i32 (%struct.templ.0*, i32)* @_ZN5templIdE3fooEi
 
 // CHECK: define linkonce_odr i32 @_ZN1S3fooEi.sse4.2(%struct.S* %this, i32)
 // CHECK: ret i32 0
 
 // CHECK: declare i32 @_ZN1S3fooEi.arch_sandybridge(%struct.S*, i32)
 
 // CHECK: define linkonce_odr i32 @_ZN1S3fooEi.arch_ivybridge(%struct.S* %this, i32)
 // CHECK: ret i32 1
 
 // CHECK: define linkonce_odr i32 @_ZN1S3fooEi(%struct.S* %this, i32)
 // CHECK: ret i32 2
 

test/CodeGenCXX/attr-target-mv-out-of-line-defs.cpp

 
 // CHECK: define i32 @_ZN1S3fooEi.arch_ivybridge(%struct.S* %this, i32)
 // CHECK: ret i32 1
 
 // CHECK: define i32 @_Z3barv()
 // CHECK: %s = alloca %struct.S, align 1
 // CHECK: %call = call i32 @_ZN1S3fooEi.ifunc(%struct.S* %s, i32 0)
 
-// CHECK: define i32 (%struct.S*, i32)* @_ZN1S3fooEi.resolver()
+// CHECK: define i32 (%struct.S*, i32)* @_ZN1S3fooEi.resolver() comdat
 // CHECK: ret i32 (%struct.S*, i32)* @_ZN1S3fooEi.arch_sandybridge
 // CHECK: ret i32 (%struct.S*, i32)* @_ZN1S3fooEi.arch_ivybridge
 // CHECK: ret i32 (%struct.S*, i32)* @_ZN1S3fooEi.sse4.2
 // CHECK: ret i32 (%struct.S*, i32)* @_ZN1S3fooEi
 
 // CHECK: declare i32 @_ZN1S3fooEi.arch_sandybridge(%struct.S*, i32)

test/CodeGenCXX/attr-target-mv-overloads.cpp

 // CHECK: ret i32 1
 // CHECK: define i32 @_Z12foo_overloadv()
 // CHECK: ret i32 2
 
 // CHECK: define i32 @_Z4bar2v()
 // CHECK: call i32 @_Z12foo_overloadv.ifunc()
 // CHECK: call i32 @_Z12foo_overloadi.ifunc(i32 1)
 
-// CHECK: define i32 ()* @_Z12foo_overloadv.resolver()
+// CHECK: define i32 ()* @_Z12foo_overloadv.resolver() comdat
 // CHECK: ret i32 ()* @_Z12foo_overloadv.arch_sandybridge
 // CHECK: ret i32 ()* @_Z12foo_overloadv.arch_ivybridge
 // CHECK: ret i32 ()* @_Z12foo_overloadv.sse4.2
 // CHECK: ret i32 ()* @_Z12foo_overloadv
 
-// CHECK: define i32 (i32)* @_Z12foo_overloadi.resolver()
+// CHECK: define i32 (i32)* @_Z12foo_overloadi.resolver() comdat
 // CHECK: ret i32 (i32)* @_Z12foo_overloadi.arch_sandybridge
 // CHECK: ret i32 (i32)* @_Z12foo_overloadi.arch_ivybridge
 // CHECK: ret i32 (i32)* @_Z12foo_overloadi.sse4.2
 // CHECK: ret i32 (i32)* @_Z12foo_overloadi
 
 // CHECK: declare i32 @_Z12foo_overloadv.arch_sandybridge()
 // CHECK: declare i32 @_Z12foo_overloadi.arch_sandybridge(i32)