PR32042: Create inlined debug info for EmitInlinedInheritingCXXConstructorCall.

When clang emits an inheriting C++ constructor it may inline code
during the CodeGen phase. This patch ensures that any debug info in
this inlined code gets a proper inlined location. Otherwise we can end
up with invalid debug info metadata, since all inlined local variables
and function arguments would be reparented into the call site.

Analogous to ApplyInlineLocation this patch introduces a
ApplyInlineDebugLocation scoped helper to facilitate entering an
inlined scope and cleaning up afterwards.

This fixes one of the issues discovered in PR32042.

rdar://problem/30679307

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@296388 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 95 insertions, 23 deletions

diff --git a/lib/CodeGen/CGDebugInfo.cpp b/lib/CodeGen/CGDebugInfo.cpp
index acfe0a4d7d..703498755c 100644
--- a/lib/CodeGen/CGDebugInfo.cpp
+++ b/lib/CodeGen/CGDebugInfo.cpp
@@ -107,8 +107,8 @@ void ApplyDebugLocation::init(SourceLocation TemporaryLocation,
 
   // Construct a location that has a valid scope, but no line info.
   assert(!DI->LexicalBlockStack.empty());
-  CGF->Builder.SetCurrentDebugLocation(
-      llvm::DebugLoc::get(0, 0, DI->LexicalBlockStack.back()));
+  CGF->Builder.SetCurrentDebugLocation(llvm::DebugLoc::get(
+      0, 0, DI->LexicalBlockStack.back(), DI->getInlinedAt()));
 }
 
 ApplyDebugLocation::ApplyDebugLocation(CodeGenFunction &CGF, const Expr *E)
@@ -134,6 +134,30 @@ ApplyDebugLocation::~ApplyDebugLocation() {
     CGF->Builder.SetCurrentDebugLocation(std::move(OriginalLocation));
 }
 
+ApplyInlineDebugLocation::ApplyInlineDebugLocation(CodeGenFunction &CGF,
+                                                   GlobalDecl InlinedFn)
+    : CGF(&CGF) {
+  if (!CGF.getDebugInfo()) {
+    this->CGF = nullptr;
+    return;
+  }
+  auto &DI = *CGF.getDebugInfo();
+  SavedLocation = DI.getLocation();
+  assert((DI.getInlinedAt() ==
+          CGF.Builder.getCurrentDebugLocation()->getInlinedAt()) &&
+         "CGDebugInfo and IRBuilder are out of sync");
+
+  DI.EmitInlineFunctionStart(CGF.Builder, InlinedFn);
+}
+
+ApplyInlineDebugLocation::~ApplyInlineDebugLocation() {
+  if (!CGF)
+    return;
+  auto &DI = *CGF->getDebugInfo();
+  DI.EmitInlineFunctionEnd(CGF->Builder);
+  DI.EmitLocation(CGF->Builder, SavedLocation);
+}
+
 void CGDebugInfo::setLocation(SourceLocation Loc) {
   // If the new location isn't valid return.
   if (Loc.isInvalid())
@@ -2871,28 +2895,40 @@ void CGDebugInfo::collectVarDeclProps(const VarDecl *VD, llvm::DIFile *&Unit,
  VDContext = getContextDescriptor(cast<Decl>(DC), Mod ? Mod : TheCU);
 }
 
-llvm::DISubprogram *
-CGDebugInfo::getFunctionForwardDeclaration(const FunctionDecl *FD) {
+llvm::DISubprogram *CGDebugInfo::getFunctionFwdDeclOrStub(GlobalDecl GD,
+                                                          bool Stub) {
   llvm::DINodeArray TParamsArray;
   StringRef Name, LinkageName;
   llvm::DINode::DIFlags Flags = llvm::DINode::FlagZero;
-  SourceLocation Loc = FD->getLocation();
+  SourceLocation Loc = GD.getDecl()->getLocation();
   llvm::DIFile *Unit = getOrCreateFile(Loc);
   llvm::DIScope *DContext = Unit;
   unsigned Line = getLineNumber(Loc);
-
-  collectFunctionDeclProps(FD, Unit, Name, LinkageName, DContext,
+  collectFunctionDeclProps(GD, Unit, Name, LinkageName, DContext,
                            TParamsArray, Flags);
+  auto *FD = dyn_cast<FunctionDecl>(GD.getDecl());
+
   // Build function type.
   SmallVector<QualType, 16> ArgTypes;
-  for (const ParmVarDecl *Parm: FD->parameters())
-    ArgTypes.push_back(Parm->getType());
+  if (FD)
+    for (const ParmVarDecl *Parm : FD->parameters())
+      ArgTypes.push_back(Parm->getType());
   CallingConv CC = FD->getType()->castAs<FunctionType>()->getCallConv();
   QualType FnType = CGM.getContext().getFunctionType(
       FD->getReturnType(), ArgTypes, FunctionProtoType::ExtProtoInfo(CC));
+  if (Stub) {
+    return DBuilder.createFunction(
+        DContext, Name, LinkageName, Unit, Line,
+        getOrCreateFunctionType(GD.getDecl(), FnType, Unit),
+        !FD->isExternallyVisible(),
+        /* isDefinition = */ true, 0, Flags, CGM.getLangOpts().Optimize,
+        TParamsArray.get(), getFunctionDeclaration(FD));
+  }
+
   llvm::DISubprogram *SP = DBuilder.createTempFunctionFwdDecl(
       DContext, Name, LinkageName, Unit, Line,
-      getOrCreateFunctionType(FD, FnType, Unit), !FD->isExternallyVisible(),
+      getOrCreateFunctionType(GD.getDecl(), FnType, Unit),
+      !FD->isExternallyVisible(),
       /* isDefinition = */ false, 0, Flags, CGM.getLangOpts().Optimize,
       TParamsArray.get(), getFunctionDeclaration(FD));
   const auto *CanonDecl = cast<FunctionDecl>(FD->getCanonicalDecl());
@@ -2902,6 +2938,16 @@ CGDebugInfo::getFunctionForwardDeclaration(const FunctionDecl *FD) {
   return SP;
 }
 
+llvm::DISubprogram *
+CGDebugInfo::getFunctionForwardDeclaration(GlobalDecl GD) {
+  return getFunctionFwdDeclOrStub(GD, /* Stub = */ false);
+}
+
+llvm::DISubprogram *
+CGDebugInfo::getFunctionStub(GlobalDecl GD) {
+  return getFunctionFwdDeclOrStub(GD, /* Stub = */ true);
+}
+
 llvm::DIGlobalVariable *
 CGDebugInfo::getGlobalVariableForwardDeclaration(const VarDecl *VD) {
   QualType T;
@@ -3173,6 +3219,27 @@ void CGDebugInfo::EmitFunctionDecl(GlobalDecl GD, SourceLocation Loc,
       TParamsArray.get(), getFunctionDeclaration(D)));
 }
 
+void CGDebugInfo::EmitInlineFunctionStart(CGBuilderTy &Builder, GlobalDecl GD) {
+  const auto *FD = cast<FunctionDecl>(GD.getDecl());
+  // If there is a subprogram for this function available then use it.
+  auto FI = SPCache.find(FD->getCanonicalDecl());
+  llvm::DISubprogram *SP = nullptr;
+  if (FI != SPCache.end())
+    SP = dyn_cast_or_null<llvm::DISubprogram>(FI->second);
+  if (!SP)
+    SP = getFunctionStub(GD);
+  FnBeginRegionCount.push_back(LexicalBlockStack.size());
+  LexicalBlockStack.emplace_back(SP);
+  setInlinedAt(Builder.getCurrentDebugLocation());
+  EmitLocation(Builder, FD->getLocation());
+}
+
+void CGDebugInfo::EmitInlineFunctionEnd(CGBuilderTy &Builder) {
+  assert(CurInlinedAt && "unbalanced inline scope stack");
+  EmitFunctionEnd(Builder);
+  setInlinedAt(llvm::DebugLoc(CurInlinedAt).getInlinedAt());
+}
+
 void CGDebugInfo::EmitLocation(CGBuilderTy &Builder, SourceLocation Loc) {
   // Update our current location
   setLocation(Loc);
@@ -3182,7 +3249,7 @@ void CGDebugInfo::EmitLocation(CGBuilderTy &Builder, SourceLocation Loc) {
 
   llvm::MDNode *Scope = LexicalBlockStack.back();
   Builder.SetCurrentDebugLocation(llvm::DebugLoc::get(
-      getLineNumber(CurLoc), getColumnNumber(CurLoc), Scope));
+      getLineNumber(CurLoc), getColumnNumber(CurLoc), Scope, CurInlinedAt));
 }
 
 void CGDebugInfo::CreateLexicalBlock(SourceLocation Loc) {
@@ -3200,8 +3267,9 @@ void CGDebugInfo::EmitLexicalBlockStart(CGBuilderTy &Builder,
   setLocation(Loc);
 
   // Emit a line table change for the current location inside the new scope.
-  Builder.SetCurrentDebugLocation(llvm::DebugLoc::get(
-      getLineNumber(Loc), getColumnNumber(Loc), LexicalBlockStack.back()));
+  Builder.SetCurrentDebugLocation(
+      llvm::DebugLoc::get(getLineNumber(Loc), getColumnNumber(Loc),
+                          LexicalBlockStack.back(), CurInlinedAt));
 
   if (DebugKind <= codegenoptions::DebugLineTablesOnly)
     return;
@@ -3387,9 +3455,10 @@ void CGDebugInfo::EmitDeclare(const VarDecl *VD, llvm::Value *Storage,
                                                   Line, Ty, Align);
 
       // Insert an llvm.dbg.declare into the current block.
-      DBuilder.insertDeclare(Storage, D, DBuilder.createExpression(Expr),
-                             llvm::DebugLoc::get(Line, Column, Scope),
-                             Builder.GetInsertBlock());
+      DBuilder.insertDeclare(
+          Storage, D, DBuilder.createExpression(Expr),
+          llvm::DebugLoc::get(Line, Column, Scope, CurInlinedAt),
+          Builder.GetInsertBlock());
       return;
     } else if (isa<VariableArrayType>(VD->getType()))
       Expr.push_back(llvm::dwarf::DW_OP_deref);
@@ -3420,9 +3489,10 @@ void CGDebugInfo::EmitDeclare(const VarDecl *VD, llvm::Value *Storage,
             Flags | llvm::DINode::FlagArtificial, FieldAlign);
 
         // Insert an llvm.dbg.declare into the current block.
-        DBuilder.insertDeclare(Storage, D, DBuilder.createExpression(Expr),
-                               llvm::DebugLoc::get(Line, Column, Scope),
-                               Builder.GetInsertBlock());
+        DBuilder.insertDeclare(
+            Storage, D, DBuilder.createExpression(Expr),
+            llvm::DebugLoc::get(Line, Column, Scope, CurInlinedAt),
+            Builder.GetInsertBlock());
       }
     }
   }
@@ -3438,7 +3508,7 @@ void CGDebugInfo::EmitDeclare(const VarDecl *VD, llvm::Value *Storage,
 
   // Insert an llvm.dbg.declare into the current block.
   DBuilder.insertDeclare(Storage, D, DBuilder.createExpression(Expr),
-                         llvm::DebugLoc::get(Line, Column, Scope),
+                         llvm::DebugLoc::get(Line, Column, Scope, CurInlinedAt),
                          Builder.GetInsertBlock());
 }
 
@@ -3519,7 +3589,8 @@ void CGDebugInfo::EmitDeclareOfBlockDeclRefVariable(
       Line, Ty, false, llvm::DINode::FlagZero, Align);
 
   // Insert an llvm.dbg.declare into the current block.
-  auto DL = llvm::DebugLoc::get(Line, Column, LexicalBlockStack.back());
+  auto DL =
+      llvm::DebugLoc::get(Line, Column, LexicalBlockStack.back(), CurInlinedAt);
   if (InsertPoint)
     DBuilder.insertDeclare(Storage, D, DBuilder.createExpression(addr), DL,
                            InsertPoint);
@@ -3687,12 +3758,13 @@ void CGDebugInfo::EmitDeclareOfBlockLiteralArgVariable(const CGBlockInfo &block,
     // Insert an llvm.dbg.value into the current block.
     DBuilder.insertDbgValueIntrinsic(
         LocalAddr, 0, debugVar, DBuilder.createExpression(),
-        llvm::DebugLoc::get(line, column, scope), Builder.GetInsertBlock());
+        llvm::DebugLoc::get(line, column, scope, CurInlinedAt),
+        Builder.GetInsertBlock());
   }
 
   // Insert an llvm.dbg.declare into the current block.
   DBuilder.insertDeclare(Arg, debugVar, DBuilder.createExpression(),
-                         llvm::DebugLoc::get(line, column, scope),
+                         llvm::DebugLoc::get(line, column, scope, CurInlinedAt),
                          Builder.GetInsertBlock());
 }