ArgumentPromotion should copy all metadata to new Function

[tejohnson]

Summary

ArgumentPromotion had code to specifically move the dbg metadata over to
the new function, but other metadata such as the function_entry_count
!prof metadata was not. Replace code that moved dbg metadata with a call
to copyMetadata. The old metadata is automatically removed when the old
Function is removed.

[davidxl]

lgtm

lib/Transforms/IPO/ArgumentPromotion.cpp

doPromotion(Function *F, SmallPtrSetImpl<Argument *> &ArgsToPromote,
 
   // Construct the new function type using the new arguments.
   FunctionType *NFTy = FunctionType::get(RetTy, Params, FTy->isVarArg());
 
   // Create the new function body and insert it into the module.
   Function *NF = Function::Create(NFTy, F->getLinkage(), F->getAddressSpace(),
                                   F->getName());
   NF->copyAttributesFrom(F);
-
-  // Patch the pointer to LLVM function in debug info descriptor.
-  NF->setSubprogram(F->getSubprogram());
-  F->setSubprogram(nullptr);
+  NF->copyMetadata(F, 0);
 
   LLVM_DEBUG(dbgs() << "ARG PROMOTION:  Promoting to:" << *NF << "\n"
                     << "From: " << *F);
 
   // Recompute the parameter attributes list based on the new arguments for
   // the function.
   NF->setAttributes(AttributeList::get(F->getContext(), PAL.getFnAttributes(),
                                        PAL.getRetAttributes(), ArgAttrVec));

test/Transforms/ArgumentPromotion/profile.ll

 ; RUN: opt -argpromotion -mem2reg -S < %s | FileCheck %s
 target datalayout = "E-p:64:64:64-a0:0:8-f32:32:32-f64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-v64:64:64-v128:128:128"
 
-; Checks if !prof metadata is corret in deadargelim.
+; Checks if !prof metadata is correct after argpromotion
 
 define void @caller() #0 {
   %x = alloca i32
   store i32 42, i32* %x
-  call void @promote_i32_ptr(i32* %x), !prof !0
-; CHECK: call void @promote_i32_ptr(i32 42), !prof ![[PROF:[0-9]]]
+  call void @promote_i32_ptr(i32* %x), !prof !6
+; CHECK: call void @promote_i32_ptr(i32 42), !prof ![[PROF:[0-9]+]]
   ret void
 }
 
-define internal void @promote_i32_ptr(i32* %xp) {
+; CHECK: define internal void @promote_i32_ptr(i32 %xp.val) !dbg ![[DBG:[0-9]+]] !prof ![[FUNCPROF:[0-9]+]]
+define internal void @promote_i32_ptr(i32* %xp) !dbg !7 !prof !12 {
   %x = load i32, i32* %xp
   call void @use_i32(i32 %x)
   ret void
 }
 
 declare void @use_i32(i32)
 
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!3, !4, !5}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !1, producer: "clang version 9.0.0 (trunk 353186) (llvm/trunk 353190)", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !2, nameTableKind: None)
+!1 = !DIFile(filename: "profile.cc", directory: ".")
+!2 = !{}
+!3 = !{i32 2, !"Dwarf Version", i32 4}
+!4 = !{i32 2, !"Debug Info Version", i32 3}
+!5 = !{i32 1, !"wchar_size", i32 4}
 ; CHECK: ![[PROF]] = !{!"branch_weights", i32 30}
-!0 = !{!"branch_weights", i32 30}
+!6 = !{!"branch_weights", i32 30}
+; CHECK: ![[DBG]] = distinct !DISubprogram(name: "promote_i32_ptr"
+!7 = distinct !DISubprogram(name: "promote_i32_ptr", linkageName: "_ZL15promote_i32_ptrPi", scope: !1, file: !1, line: 2, type: !8, scopeLine: 2, flags: DIFlagPrototyped, spFlags: DISPFlagLocalToUnit | DISPFlagDefinition, unit: !0, retainedNodes: !2)
+!8 = !DISubroutineType(types: !9)
+!9 = !{null, !10}
+!10 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !11, size: 64)
+!11 = !DIBasicType(name: "int", size: 32, encoding: DW_ATE_signed)
+; CHECK: ![[FUNCPROF]] = !{!"function_entry_count", i64 331}
+!12 = !{!"function_entry_count", i64 331}