Revert "Strip debug info when inlining into a nodebug function."

This reverts commit r296488.

As noted by David Blaikie on llvm-commits, I overlooked the case of a
debug function being inlined into a nodebug function being inlined
into a debug function.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@297163 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Transforms/Utils/InlineFunction.cpp

@@ -1343,26 +1343,22 @@ static bool allocaWouldBeStaticInEntry(const AllocaInst *AI ) {
   return isa<Constant>(AI->getArraySize()) && !AI->isUsedWithInAlloca();
 }
 
-/// Update inlined instructions' line numbers to to encode location where these
-/// instructions are inlined.  Also strip all debug intrinsics that were inlined
-/// into a nodebug function; there is no debug info the backend could produce
-/// for a function without a DISubprogram attachment.
-static void fixupDebugInfo(Function *Fn, Function::iterator FI,
-                           Instruction *TheCall, bool CalleeHasDebugInfo) {
-  bool CallerHasDebugInfo = Fn->getSubprogram();
-  bool StripDebugInfo = !CallerHasDebugInfo && CalleeHasDebugInfo;
-  SmallVector<DbgInfoIntrinsic *, 8> IntrinsicsToErase;
+/// Update inlined instructions' line numbers to
+/// to encode location where these instructions are inlined.
+static void fixupLineNumbers(Function *Fn, Function::iterator FI,
+                             Instruction *TheCall, bool CalleeHasDebugInfo) {
   const DebugLoc &TheCallDL = TheCall->getDebugLoc();
+  if (!TheCallDL)
+    return;
 
   auto &Ctx = Fn->getContext();
-  DILocation *InlinedAtNode = nullptr;
+  DILocation *InlinedAtNode = TheCallDL;
 
   // Create a unique call site, not to be confused with any other call from the
   // same location.
-  if (TheCallDL)
-    InlinedAtNode = DILocation::getDistinct(
-        Ctx, TheCallDL->getLine(), TheCallDL->getColumn(),
-        TheCallDL->getScope(), TheCallDL->getInlinedAt());
+  InlinedAtNode = DILocation::getDistinct(
+      Ctx, InlinedAtNode->getLine(), InlinedAtNode->getColumn(),
+      InlinedAtNode->getScope(), InlinedAtNode->getInlinedAt());
 
   // Cache the inlined-at nodes as they're built so they are reused, without
   // this every instruction's inlined-at chain would become distinct from each
@@ -1372,17 +1368,6 @@ static void fixupDebugInfo(Function *Fn, Function::iterator FI,
   for (; FI != Fn->end(); ++FI) {
     for (BasicBlock::iterator BI = FI->begin(), BE = FI->end();
          BI != BE; ++BI) {
-      if (StripDebugInfo) {
-        // Inlining into a nodebug function.
-        if (auto *DI = dyn_cast<DbgInfoIntrinsic>(BI))
-          // Mark dead debug intrinsics for deletion.
-          IntrinsicsToErase.push_back(DI);
-        else
-          // Remove the dangling debug location.
-          BI->setDebugLoc(DebugLoc());
-        continue;
-      }
-
       if (DebugLoc DL = BI->getDebugLoc()) {
         BI->setDebugLoc(
             updateInlinedAtInfo(DL, InlinedAtNode, BI->getContext(), IANodes));
@@ -1405,9 +1390,6 @@ static void fixupDebugInfo(Function *Fn, Function::iterator FI,
       BI->setDebugLoc(TheCallDL);
     }
   }
-
-  for (auto *DI : IntrinsicsToErase)
-    DI->eraseFromParent();
 }
 /// Update the block frequencies of the caller after a callee has been inlined.
 ///
@@ -1728,8 +1710,8 @@ bool llvm::InlineFunction(CallSite CS, InlineFunctionInfo &IFI,
     // For 'nodebug' functions, the associated DISubprogram is always null.
     // Conservatively avoid propagating the callsite debug location to
     // instructions inlined from a function whose DISubprogram is not null.
-    fixupDebugInfo(Caller, FirstNewBlock, TheCall,
-                   CalledFunc->getSubprogram() != nullptr);
+    fixupLineNumbers(Caller, FirstNewBlock, TheCall,
+                     CalledFunc->getSubprogram() != nullptr);
 
     // Clone existing noalias metadata if necessary.
     CloneAliasScopeMetadata(CS, VMap);

test/Transforms/Inline/local-as-metadata-undominated-use.ll

@@ -16,14 +16,14 @@ entry:
 }
 
 ; CHECK-LABEL: define i32 @caller(
-define i32 @caller(i32 %i) !dbg !3 {
+define i32 @caller(i32 %i) {
 ; CHECK-NEXT: entry:
 entry:
 ; Although the inliner shouldn't crash, it can't be expected to get the
 ; "correct" SSA value since its assumptions have been violated.
 ; CHECK-NEXT:   tail call void @llvm.dbg.value(metadata ![[EMPTY:[0-9]+]],
 ; CHECK-NEXT:   %{{.*}} = add nsw
-  %call = tail call i32 @foo(i32 %i), !dbg !14
+  %call = tail call i32 @foo(i32 %i)
   ret i32 %call
 }
 
@@ -34,9 +34,9 @@ declare void @llvm.dbg.value(metadata, i64, metadata, metadata)
 
 !0 = distinct !DICompileUnit(language: DW_LANG_C99, file: !1, producer: "clang version 3.9.0 (trunk 265634) (llvm/trunk 265637)", isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !2)
 !1 = !DIFile(filename: "t.c", directory: "/path/to/tests")
+
 ; CHECK: ![[EMPTY]] = !{}
 !2 = !{}
-!3 = distinct !DISubprogram(name: "caller", scope: !1, file: !1, line: 3, type: !5, isLocal: false, isDefinition: true, scopeLine: 3, flags: DIFlagPrototyped, isOptimized: true, unit: !0)
 !4 = distinct !DISubprogram(name: "foo", scope: !1, file: !1, line: 2, type: !5, isLocal: false, isDefinition: true, scopeLine: 2, flags: DIFlagPrototyped, isOptimized: true, unit: !0)
 !5 = !DISubroutineType(types: !6)
 !6 = !{!7, !7}
@@ -47,4 +47,3 @@ declare void @llvm.dbg.value(metadata, i64, metadata, metadata)
 !11 = !DILocation(line: 2, column: 13, scope: !4)
 !12 = !DILocation(line: 2, column: 27, scope: !4)
 !13 = !DILocation(line: 2, column: 18, scope: !4)
-!14 = !DILocation(line: 3, scope: !3)