[CIR][CIRGen][Builtin] Support BI__builtin_operator_new and BI__builtin_operator_delete (#1035)

The added test cases are from [OG's
counterpart](https://github.com/llvm/clangir/blob/f9c5477ee10c9bc005ffbfe698691cc02193ea81/clang/test/CodeGenCXX/builtin-operator-new-delete.cpp#L7).
I changed run option to -std=c++17 to support
[std::align_val_t](https://en.cppreference.com/w/cpp/memory/new/align_val_t)

Author: ghehg

clang/lib/CIR/CodeGen/CIRGenBuiltin.cpp

@@ -1838,9 +1838,12 @@ RValue CIRGenFunction::buildBuiltinExpr(const GlobalDecl GD, unsigned BuiltinID,
   case Builtin::BI__builtin_function_start:
     llvm_unreachable("BI__builtin_function_start NYI");
   case Builtin::BI__builtin_operator_new:
-    llvm_unreachable("BI__builtin_operator_new NYI");
+    return buildBuiltinNewDeleteCall(
+        E->getCallee()->getType()->castAs<FunctionProtoType>(), E, false);
   case Builtin::BI__builtin_operator_delete:
-    llvm_unreachable("BI__builtin_operator_delete NYI");
+    buildBuiltinNewDeleteCall(
+        E->getCallee()->getType()->castAs<FunctionProtoType>(), E, true);
+    return RValue::get(nullptr);
   case Builtin::BI__builtin_is_aligned:
     llvm_unreachable("BI__builtin_is_aligned NYI");
   case Builtin::BI__builtin_align_up:

clang/lib/CIR/CodeGen/CIRGenExprCXX.cpp

@@ -1175,6 +1175,23 @@ static RValue buildNewDeleteCall(CIRGenFunction &CGF,
   return RV;
 }
 
+RValue CIRGenFunction::buildBuiltinNewDeleteCall(const FunctionProtoType *type,
+                                                 const CallExpr *theCall,
+                                                 bool isDelete) {
+  CallArgList args;
+  buildCallArgs(args, type, theCall->arguments());
+  // Find the allocation or deallocation function that we're calling.
+  ASTContext &ctx = getContext();
+  DeclarationName name =
+      ctx.DeclarationNames.getCXXOperatorName(isDelete ? OO_Delete : OO_New);
+
+  for (auto *decl : ctx.getTranslationUnitDecl()->lookup(name))
+    if (auto *fd = dyn_cast<FunctionDecl>(decl))
+      if (ctx.hasSameType(fd->getType(), QualType(type, 0)))
+        return buildNewDeleteCall(*this, fd, type, args);
+  llvm_unreachable("predeclared global operator new/delete is missing");
+}
+
 void CIRGenFunction::buildDeleteCall(const FunctionDecl *DeleteFD,
                                      mlir::Value Ptr, QualType DeleteTy,
                                      mlir::Value NumElements,

clang/lib/CIR/CodeGen/CIRGenFunction.h

@@ -729,6 +729,9 @@ class CIRGenFunction : public CIRGenTypeCache {
                        QualType DeleteTy, mlir::Value NumElements = nullptr,
                        CharUnits CookieSize = CharUnits());
 
+  RValue buildBuiltinNewDeleteCall(const FunctionProtoType *type,
+                                   const CallExpr *theCallExpr, bool isDelete);
+
   mlir::Value buildDynamicCast(Address ThisAddr, const CXXDynamicCastExpr *DCE);
 
   mlir::Value createLoad(const clang::VarDecl *VD, const char *Name);

clang/test/CIR/CodeGen/new-null.cpp

@@ -1,6 +1,6 @@
-// RUN: %clang_cc1 -std=c++14 -triple x86_64-unknown-linux-gnu %s -fclangir -emit-cir -o %t.cir
+// RUN: %clang_cc1 -std=c++17 -triple x86_64-unknown-linux-gnu %s -fclangir -emit-cir -o %t.cir
 // RUN: FileCheck --input-file=%t.cir -check-prefix=CIR %s
-// RUN: %clang_cc1 -std=c++14 -triple x86_64-unknown-linux-gnu %s -fclangir -emit-llvm -o %t.ll
+// RUN: %clang_cc1 -std=c++17 -triple x86_64-unknown-linux-gnu %s -fclangir -emit-llvm -o %t.ll
 // RUN: FileCheck --input-file=%t.ll -check-prefix=LLVM %s
 
 // TODO: This file is inspired by clang/test/CodeGenCXX/new.cpp, add all tests from it.
@@ -16,6 +16,8 @@ void *operator new[](size_t);
 
 namespace std {
   struct nothrow_t {};
+  enum class align_val_t : size_t { __zero = 0,
+                                  __max = (size_t)-1 };
 }
 std::nothrow_t nothrow;
 
@@ -76,4 +78,45 @@ namespace test15 {
   void test0b(void *p) {
     new (p, true) A();
   }
-}
+}
+
+extern "C" void test_basic() {
+  __builtin_operator_delete(__builtin_operator_new(4));
+  // CIR-LABEL: cir.func @test_basic
+  // CIR: [[P:%.*]] = cir.call @_Znwm({{%.*}}) : (!u64i) -> !cir.ptr<!void>
+  // CIR: cir.call @_ZdlPv([[P]]) : (!cir.ptr<!void>) -> ()
+  // CIR: cir.return
+
+  // LLVM-LABEL: define{{.*}} void @test_basic()
+  // LLVM: [[P:%.*]] = call ptr @_Znwm(i64 4)
+  // LLVM: call void @_ZdlPv(ptr [[P]])
+  // LLVM: ret void
+}
+
+extern "C" void test_aligned_alloc() {
+  __builtin_operator_delete(__builtin_operator_new(4, std::align_val_t(4)), std::align_val_t(4));
+
+  // CIR-LABEL: cir.func @test_aligned_alloc
+  // CIR: [[P:%.*]] = cir.call @_ZnwmSt11align_val_t({{%.*}}, {{%.*}}) : (!u64i, !u64i) -> !cir.ptr<!void>
+  // CIR: cir.call @_ZdlPvSt11align_val_t([[P]], {{%.*}}) : (!cir.ptr<!void>, !u64i) -> ()
+  // CIR: cir.return
+
+  // LLVM-LABEL: define{{.*}} void @test_aligned_alloc()
+  // LLVM: [[P:%.*]] = call ptr @_ZnwmSt11align_val_t(i64 4, i64 4)
+  // LLVM: call void @_ZdlPvSt11align_val_t(ptr [[P]], i64 4)
+  // LLVM: ret void
+}
+
+extern "C" void test_sized_delete() {
+  __builtin_operator_delete(__builtin_operator_new(4), 4);
+
+  // CIR-LABEL: cir.func @test_sized_delete
+  // CIR: [[P:%.*]] = cir.call @_Znwm({{%.*}}) : (!u64i) -> !cir.ptr<!void>
+  // CIR: cir.call @_ZdlPvm([[P]], {{%.*}}) : (!cir.ptr<!void>, !u64i) -> ()
+  // CIR: cir.return
+
+  // LLVM-LABEL: define{{.*}} void @test_sized_delete()
+  // LLVM: [[P:%.*]] = call ptr @_Znwm(i64 4)
+  // LLVM: call void @_ZdlPvm(ptr [[P]], i64 4)
+  // LLVM: ret void
+}