[Clang][NFCI] Remove CallExpr::CreateTemporary()

[zyn0217]

It turned out that we don't necessarily need a CallExpr to funnel Type/ValueKind/SourceLocation into TryCopyInitialization(), whereas an OpaqueValueExpr is sufficient.

Fixes #130824

[llvmbot]

@llvm/pr-subscribers-clang

Author: Younan Zhang (zyn0217)

Changes

It turned out that we don't necessarily need a CallExpr to funnel Type/ValueKind/SourceLocation into TryCopyInitialization(), whereas an OpaqueValueExpr is sufficient.

Fixes #130824

---

Full diff: https://github.com/llvm/llvm-project/pull/130921.diff

3 Files Affected:

• (modified) clang/include/clang/AST/Expr.h (-12)
• (modified) clang/lib/AST/Expr.cpp (+3-15)
• (modified) clang/lib/Sema/SemaOverload.cpp (+3-5)

diff --git a/clang/include/clang/AST/Expr.h b/clang/include/clang/AST/Expr.h
index cfe49acf20b77..b81f3a403baf6 100644
--- a/clang/include/clang/AST/Expr.h
+++ b/clang/include/clang/AST/Expr.h
@@ -3005,18 +3005,6 @@ class CallExpr : public Expr {
                           FPOptionsOverride FPFeatures, unsigned MinNumArgs = 0,
                           ADLCallKind UsesADL = NotADL);
 
-  /// Create a temporary call expression with no arguments in the memory
-  /// pointed to by Mem. Mem must points to at least sizeof(CallExpr)
-  /// + sizeof(Stmt *) bytes of storage, aligned to alignof(CallExpr):
-  ///
-  /// \code{.cpp}
-  ///   alignas(CallExpr) char Buffer[sizeof(CallExpr) + sizeof(Stmt *)];
-  ///   CallExpr *TheCall = CallExpr::CreateTemporary(Buffer, etc);
-  /// \endcode
-  static CallExpr *CreateTemporary(void *Mem, Expr *Fn, QualType Ty,
-                                   ExprValueKind VK, SourceLocation RParenLoc,
-                                   ADLCallKind UsesADL = NotADL);
-
   /// Create an empty call expression, for deserialization.
   static CallExpr *CreateEmpty(const ASTContext &Ctx, unsigned NumArgs,
                                bool HasFPFeatures, EmptyShell Empty);
diff --git a/clang/lib/AST/Expr.cpp b/clang/lib/AST/Expr.cpp
index 1dde64f193dbd..2001d01365a64 100644
--- a/clang/lib/AST/Expr.cpp
+++ b/clang/lib/AST/Expr.cpp
@@ -1509,16 +1509,6 @@ CallExpr *CallExpr::Create(const ASTContext &Ctx, Expr *Fn,
                             RParenLoc, FPFeatures, MinNumArgs, UsesADL);
 }
 
-CallExpr *CallExpr::CreateTemporary(void *Mem, Expr *Fn, QualType Ty,
-                                    ExprValueKind VK, SourceLocation RParenLoc,
-                                    ADLCallKind UsesADL) {
-  assert(!(reinterpret_cast<uintptr_t>(Mem) % alignof(CallExpr)) &&
-         "Misaligned memory in CallExpr::CreateTemporary!");
-  return new (Mem) CallExpr(CallExprClass, Fn, /*PreArgs=*/{}, /*Args=*/{}, Ty,
-                            VK, RParenLoc, FPOptionsOverride(),
-                            /*MinNumArgs=*/0, UsesADL);
-}
-
 CallExpr *CallExpr::CreateEmpty(const ASTContext &Ctx, unsigned NumArgs,
                                 bool HasFPFeatures, EmptyShell Empty) {
   unsigned SizeOfTrailingObjects =
@@ -1656,11 +1646,9 @@ SourceLocation CallExpr::getBeginLoc() const {
     if (const auto *Method =
             dyn_cast_if_present<const CXXMethodDecl>(getCalleeDecl());
         Method && Method->isExplicitObjectMemberFunction()) {
-      // Note: while we typically expect the call to have a first argument
-      // here, we can't assert it because in some cases it does not, e.g.
-      // calls created with CallExpr::CreateTemporary() during overload
-      // resolution.
-      if (getNumArgs() > 0 && getArg(0))
+      bool HasFirstArg = getNumArgs() > 0 && getArg(0);
+      assert(HasFirstArg);
+      if (HasFirstArg)
         return getArg(0)->getBeginLoc();
     }
   }
diff --git a/clang/lib/Sema/SemaOverload.cpp b/clang/lib/Sema/SemaOverload.cpp
index d3c0534b4dd0b..8d29f6bd1a0e8 100644
--- a/clang/lib/Sema/SemaOverload.cpp
+++ b/clang/lib/Sema/SemaOverload.cpp
@@ -8152,12 +8152,10 @@ void Sema::AddConversionCandidate(
   // allocator).
   QualType CallResultType = ConversionType.getNonLValueExprType(Context);
 
-  alignas(CallExpr) char Buffer[sizeof(CallExpr) + sizeof(Stmt *)];
-  CallExpr *TheTemporaryCall = CallExpr::CreateTemporary(
-      Buffer, &ConversionFn, CallResultType, VK, From->getBeginLoc());
-
+  OpaqueValueExpr OVE(ConversionFn.getBeginLoc(), CallResultType, VK,
+                      OK_Ordinary);
   ImplicitConversionSequence ICS =
-      TryCopyInitialization(*this, TheTemporaryCall, ToType,
+      TryCopyInitialization(*this, &OVE, ToType,
                             /*SuppressUserConversions=*/true,
                             /*InOverloadResolution=*/false,
                             /*AllowObjCWritebackConversion=*/false);

[zyn0217]

(Duplicate of #130919.)