[InlineFunction] Set debug loc for call to forward varargs.

[aprantl]

Superficially this looks reasonable, but could you maybe quickly explain what the transformation is doing and why this is the right location to attach?

[rnk]

In D40432#936649, @aprantl wrote:

Superficially this looks reasonable, but could you maybe quickly explain what the transformation is doing and why this is the right location to attach?

Looks reasonable to me as is. This code really just wants to modify the call argument list in place, but it happens to do it with RAUW and it forgets the debug location currently.

Thanks for the fix!

lib/Transforms/Utils/InlineFunction.cpp

for (Function::iterator BB = FirstNewBlock, E = Caller->end(); BB != E;
         if (MarkNoUnwind)
           CI->setDoesNotThrow();
 
         if (ForwardVarArgsTo && !VarArgsToForward.empty() &&
             CI->getCalledFunction() == ForwardVarArgsTo) {
           SmallVector<Value*, 6> Params(CI->arg_operands());
           Params.append(VarArgsToForward.begin(), VarArgsToForward.end());
           CallInst *Call = CallInst::Create(CI->getCalledFunction(), Params, "", CI);
+          Call->setDebugLoc(CI->getDebugLoc());
           CI->replaceAllUsesWith(Call);
           CI->eraseFromParent();
         }
       }
     }
   }
 
   // Leave lifetime markers for the static alloca's, scoping them to the

test/Transforms/CodeExtractor/PartialInlineVarArgsDebug.ll

+; RUN: opt < %s -S -partial-inliner -skip-partial-inlining-cost-analysis=true | FileCheck %s
+
+; CHECK-LABEL: @callee
+; CHECK: %mul = mul nsw i32 %v, 10, !dbg ![[DBG1:[0-9]+]]
+define i32 @callee(i32 %v, ...) !dbg !16 {
+entry:
+  %cmp = icmp sgt i32 %v, 2000, !dbg !17
+  br i1 %cmp, label %if.then, label %if.end, !dbg !19
+
+if.then:                                          ; preds = %entry
+  %mul = mul nsw i32 %v, 10, !dbg !20
+  br label %if.end, !dbg !21
+
+if.end:                                           ; preds = %if.then, %entry
+  %v2 = phi i32 [ %v, %entry ], [ %mul, %if.then ]
+  %add = add nsw i32 %v2, 200, !dbg !22
+  ret i32 %add, !dbg !23
+}
+
+; CHECK-LABEL: @caller
+; CHECK: codeRepl.i:
+; CHECK-NEXT: call void (i32, i32*, ...) @callee.1_if.then(i32 %v, i32* %mul.loc.i, i32 99), !dbg ![[DBG2:[0-9]+]]
+define i32 @caller(i32 %v) !dbg !8 {
+entry:
+  %call = call i32 (i32, ...) @callee(i32 %v, i32 99), !dbg !14
+  ret i32 %call, !dbg !15
+}
+
+; CHECK-LABEL: define internal void @callee.1_if.then
+; CHECK: br label %if.then, !dbg ![[DBG3:[0-9]+]]
+
+; CHECK: ![[DBG1]] = !DILocation(line: 10, column: 7,
+; CHECK: ![[DBG2]] = !DILocation(line: 10, column: 7,
+; CHECK: ![[DBG3]] = !DILocation(line: 10, column: 7,
+
+
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!3, !4, !5, !6}
+!llvm.ident = !{!7}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "clang version 6.0.0 (trunk 177881)", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !2)
+!1 = !DIFile(filename: "test.c", directory: "/tmp")
+!2 = !{}
+!3 = !{i32 2, !"Dwarf Version", i32 4}
+!4 = !{i32 2, !"Debug Info Version", i32 3}
+!5 = !{i32 1, !"wchar_size", i32 4}
+!6 = !{i32 1, !"min_enum_size", i32 4}
+!7 = !{!"clang version 6.0.0"}
+!8 = distinct !DISubprogram(name: "caller", scope: !1, file: !1, line: 3, type: !9, isLocal: false, isDefinition: true, scopeLine: 3, flags: DIFlagPrototyped, isOptimized: true, unit: !0, variables: !12)
+!9 = !DISubroutineType(types: !10)
+!10 = !{!11, !11}
+!11 = !DIBasicType(name: "int", size: 19, encoding: DW_ATE_signed)
+!12 = !{!13}
+!13 = !DILocalVariable(name: "v", arg: 1, scope: !8, file: !1, line: 3, type: !11)
+!14 = !DILocation(line: 5, column: 10, scope: !8)
+!15 = !DILocation(line: 5, column: 3, scope: !8)
+!16 = distinct !DISubprogram(name: "callee", scope: !1, file: !1, line: 8, type: !9, isLocal: false, isDefinition: true, scopeLine: 8, flags: DIFlagPrototyped, isOptimized: true, unit: !0, variables: !26)
+!26 = !{!27}
+!27 = !DILocalVariable(name: "v", arg: 1, scope: !16, file: !1, line: 8, type: !11)
+!17 = !DILocation(line: 9, column: 9, scope: !18)
+!18 = distinct !DILexicalBlock(scope: !16, file: !1, line: 9, column: 7)
+!19 = !DILocation(line: 9, column: 7, scope: !16)
+!20 = !DILocation(line: 10, column: 7, scope: !18)
+!21 = !DILocation(line: 10, column: 5, scope: !18)
+!22 = !DILocation(line: 11, column: 5, scope: !16)
+!36 = !DILocation(line: 12, column: 10, scope: !16)
+!23 = !DILocation(line: 12, column: 3, scope: !16)