[CGDebugInfo] Simplfiy EmitFunctionDecl parameters, NFC

[vsk]

Summary

Replace a llvm::Function * parameter with a bool, which seems harder
to set to the wrong value by accident.

[djtodoro]

LGTM! Thanks @vsk!

[echristo]

Not a huge fan of boolean parameters like this, perhaps factor out the context as well into the caller and then we don't need it at all? Something else?

[vsk]

Sorry about that, reopening per Eric's comment.

clang/lib/CodeGen/CGDebugInfo.h

void EmitFunctionStart(GlobalDecl GD, SourceLocation Loc,
                          llvm::Function *Fn, bool CurFnIsThunk,
                          CGBuilderTy &Builder);
 
   /// Start a new scope for an inlined function.
   void EmitInlineFunctionStart(CGBuilderTy &Builder, GlobalDecl GD);
   /// End an inlined function scope.
   void EmitInlineFunctionEnd(CGBuilderTy &Builder);
 
-  /// Emit debug info for a function declaration.
-  /// \p Fn is set only when a declaration for a debug call site gets created.
-  void EmitFunctionDecl(GlobalDecl GD, SourceLocation Loc,
-                        QualType FnType, llvm::Function *Fn = nullptr);
+  /// Emit debug info for a function declaration. Set \p IsDeclForCallSite if
+  /// a call site entry must reference the declaration.
+  llvm::DISubprogram *EmitFunctionDecl(GlobalDecl GD, SourceLocation Loc,
+                                       QualType FnType,
+                                       bool IsDeclForCallSite = false);
 
   /// Emit debug info for an extern function being called.
   /// This is needed for call site debug info.
   void EmitFuncDeclForCallSite(llvm::CallBase *CallOrInvoke,
                                QualType CalleeType,
                                const FunctionDecl *CalleeDecl);
 
   /// Constructs the debug code for exiting a function.

clang/lib/CodeGen/CGDebugInfo.cpp

 
   // Push the function onto the lexical block stack.
   LexicalBlockStack.emplace_back(SP);
 
   if (HasDecl)
     RegionMap[D].reset(SP);
 }
 
-void CGDebugInfo::EmitFunctionDecl(GlobalDecl GD, SourceLocation Loc,
-                                   QualType FnType, llvm::Function *Fn) {
+llvm::DISubprogram *CGDebugInfo::EmitFunctionDecl(GlobalDecl GD,
+                                                  SourceLocation Loc,
+                                                  QualType FnType,
+                                                  bool IsDeclForCallSite) {
   StringRef Name;
   StringRef LinkageName;
 
   const Decl *D = GD.getDecl();
   if (!D)
-    return;
+    return nullptr;
 
   llvm::DINode::DIFlags Flags = llvm::DINode::FlagZero;
   llvm::DIFile *Unit = getOrCreateFile(Loc);
-  bool IsDeclForCallSite = Fn ? true : false;
   llvm::DIScope *FDContext =
       IsDeclForCallSite ? Unit : getDeclContextDescriptor(D);
   llvm::DINodeArray TParamsArray;
   if (isa<FunctionDecl>(D)) {
     // If there is a DISubprogram for this function available then use it.
     collectFunctionDeclProps(GD, Unit, Name, LinkageName, FDContext,
                              TParamsArray, Flags);
   } else if (const auto *OMD = dyn_cast<ObjCMethodDecl>(D)) {

   llvm::DISubprogram::DISPFlags SPFlags = llvm::DISubprogram::SPFlagZero;
   if (CGM.getLangOpts().Optimize)
     SPFlags |= llvm::DISubprogram::SPFlagOptimized;
 
   llvm::DISubprogram *SP = DBuilder.createFunction(
       FDContext, Name, LinkageName, Unit, LineNo,
       getOrCreateFunctionType(D, FnType, Unit), ScopeLine, Flags, SPFlags,
       TParamsArray.get(), getFunctionDeclaration(D));
-
-  if (IsDeclForCallSite)
-    Fn->setSubprogram(SP);
-
   DBuilder.retainType(SP);
+  return SP;
 }
 
 void CGDebugInfo::EmitFuncDeclForCallSite(llvm::CallBase *CallOrInvoke,
                                           QualType CalleeType,
                                           const FunctionDecl *CalleeDecl) {
   auto &CGOpts = CGM.getCodeGenOpts();
   if (!CGOpts.EnableDebugEntryValues || !CGM.getLangOpts().Optimize ||
       !CallOrInvoke ||
       CGM.getCodeGenOpts().getDebugInfo() < codegenoptions::LimitedDebugInfo)
     return;
 
   auto *Func = CallOrInvoke->getCalledFunction();
   if (!Func)
     return;
 
   // If there is no DISubprogram attached to the function being called,
   // create the one describing the function in order to have complete
   // call site debug info.
   if (Func->getSubprogram())
     return;
 
-  if (!CalleeDecl->isStatic() && !CalleeDecl->isInlined())
-    EmitFunctionDecl(CalleeDecl, CalleeDecl->getLocation(), CalleeType, Func);
+  if (!CalleeDecl->isStatic() && !CalleeDecl->isInlined()) {
+    llvm::DISubprogram *SP =
+        EmitFunctionDecl(CalleeDecl, CalleeDecl->getLocation(), CalleeType,
+                         /*IsDeclForCallSite=*/true);
+    assert(SP && "Could not find decl for callee?");
+    Func->setSubprogram(SP);
+  }
 }
 
 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())