[CIR] Upstream l-value emission for ExprWithCleanups (#167938)

This adds the necessary handler for emitting an l-value for an
ExprWithCleanups expression.

Author: andykaylor

clang/include/clang/CIR/MissingFeatures.h

@@ -226,6 +226,7 @@ struct MissingFeatures {
   static bool cleanupAppendInsts() { return false; }
   static bool cleanupBranchThrough() { return false; }
   static bool cleanupIndexAndBIAdjustment() { return false; }
+  static bool cleanupWithPreservedValues() { return false; }
   static bool cleanupsToDeactivate() { return false; }
   static bool constEmitterAggILE() { return false; }
   static bool constEmitterArrayILE() { return false; }

clang/lib/CIR/CodeGen/CIRGenFunction.cpp

@@ -921,6 +921,13 @@ LValue CIRGenFunction::emitLValue(const Expr *e) {
   case Expr::CXXOperatorCallExprClass:
   case Expr::UserDefinedLiteralClass:
     return emitCallExprLValue(cast<CallExpr>(e));
+  case Expr::ExprWithCleanupsClass: {
+    const auto *cleanups = cast<ExprWithCleanups>(e);
+    RunCleanupsScope scope(*this);
+    LValue lv = emitLValue(cleanups->getSubExpr());
+    assert(!cir::MissingFeatures::cleanupWithPreservedValues());
+    return lv;
+  }
   case Expr::ParenExprClass:
     return emitLValue(cast<ParenExpr>(e)->getSubExpr());
   case Expr::GenericSelectionExprClass:

clang/test/CIR/CodeGen/temporary-materialization.cpp

@@ -0,0 +1,86 @@
+// RUN: %clang_cc1 -std=c++17 -triple x86_64-unknown-linux-gnu -fclangir -emit-cir %s -o %t.cir
+// RUN: FileCheck --input-file=%t.cir %s --check-prefix=CIR
+// RUN: %clang_cc1 -std=c++17 -triple x86_64-unknown-linux-gnu -fclangir -emit-llvm %s -o %t-cir.ll
+// RUN: FileCheck --input-file=%t-cir.ll %s --check-prefix=LLVM
+// RUN: %clang_cc1 -std=c++17 -triple x86_64-unknown-linux-gnu -emit-llvm %s -o %t.ll
+// RUN: FileCheck --input-file=%t.ll %s --check-prefix=OGCG
+
+int make_int();
+
+int test() {
+  const int &x = make_int();
+  return x;
+}
+
+//      CIR: cir.func {{.*}} @_Z4testv()
+//      CIR:   %[[TEMP_SLOT:.*]] = cir.alloca !s32i, !cir.ptr<!s32i>, ["ref.tmp0", init]
+// CIR-NEXT:   %[[X:.*]] = cir.alloca !cir.ptr<!s32i>, !cir.ptr<!cir.ptr<!s32i>>, ["x", init, const]
+// CIR-NEXT:   %[[TEMP_VALUE:.*]] = cir.call @_Z8make_intv() : () -> !s32i
+// CIR-NEXT:   cir.store{{.*}} %[[TEMP_VALUE]], %[[TEMP_SLOT]]
+// CIR-NEXT:   cir.store{{.*}} %[[TEMP_SLOT]], %[[X]]
+
+// LLVM: define {{.*}} i32 @_Z4testv()
+// LLVM:   %[[RETVAL:.*]] = alloca i32
+// LLVM:   %[[TEMP_SLOT:.*]] = alloca i32
+// LLVM:   %[[X:.*]] = alloca ptr
+// LLVM:   %[[TEMP_VALUE:.*]] = call i32 @_Z8make_intv()
+// LLVM:   store i32 %[[TEMP_VALUE]], ptr %[[TEMP_SLOT]]
+// LLVM:   store ptr %[[TEMP_SLOT]], ptr %[[X]]
+
+// OGCG: define {{.*}} i32 @_Z4testv()
+// OGCG:   %[[X:.*]] = alloca ptr
+// OGCG:   %[[TEMP_SLOT:.*]] = alloca i32
+// OGCG:   %[[TEMP_VALUE:.*]] = call noundef i32 @_Z8make_intv()
+// OGCG:   store i32 %[[TEMP_VALUE]], ptr %[[TEMP_SLOT]]
+// OGCG:   store ptr %[[TEMP_SLOT]], ptr %[[X]]
+
+int test_scoped() {
+  int x = make_int();
+  {
+    const int &y = make_int();
+    x = y;
+  }
+  return x;
+}
+
+//      CIR: cir.func {{.*}} @_Z11test_scopedv()
+//      CIR:   %[[X:.*]] = cir.alloca !s32i, !cir.ptr<!s32i>, ["x", init]
+//      CIR:   cir.scope {
+// CIR-NEXT:     %[[TEMP_SLOT:.*]] = cir.alloca !s32i, !cir.ptr<!s32i>, ["ref.tmp0", init]
+// CIR-NEXT:     %[[Y_ADDR:.*]] = cir.alloca !cir.ptr<!s32i>, !cir.ptr<!cir.ptr<!s32i>>, ["y", init, const]
+// CIR-NEXT:     %[[TEMP_VALUE:.*]] = cir.call @_Z8make_intv() : () -> !s32i
+// CIR-NEXT:     cir.store{{.*}} %[[TEMP_VALUE]], %[[TEMP_SLOT]] : !s32i, !cir.ptr<!s32i>
+// CIR-NEXT:     cir.store{{.*}} %[[TEMP_SLOT]], %[[Y_ADDR]] : !cir.ptr<!s32i>, !cir.ptr<!cir.ptr<!s32i>>
+// CIR-NEXT:     %[[Y_REF:.*]] = cir.load %[[Y_ADDR]] : !cir.ptr<!cir.ptr<!s32i>>, !cir.ptr<!s32i>
+// CIR-NEXT:     %[[Y_VALUE:.*]] = cir.load{{.*}} %[[Y_REF]] : !cir.ptr<!s32i>, !s32i
+// CIR-NEXT:     cir.store{{.*}} %[[Y_VALUE]], %[[X]] : !s32i, !cir.ptr<!s32i>
+// CIR-NEXT:   }
+
+// LLVM: define {{.*}} i32 @_Z11test_scopedv()
+// LLVM:   %[[TEMP_SLOT:.*]] = alloca i32
+// LLVM:   %[[Y_ADDR:.*]] = alloca ptr
+// LLVM:   %[[RETVAL:.*]] = alloca i32
+// LLVM:   %[[X:.*]] = alloca i32
+// LLVM:   %[[TEMP_VALUE1:.*]] = call i32 @_Z8make_intv()
+// LLVM:   store i32 %[[TEMP_VALUE1]], ptr %[[X]]
+// LLVM:   br label %[[SCOPE_LABEL:.*]]
+// LLVM: [[SCOPE_LABEL]]:
+// LLVM:   %[[TEMP_VALUE2:.*]] = call i32 @_Z8make_intv()
+// LLVM:   store i32 %[[TEMP_VALUE2]], ptr %[[TEMP_SLOT]]
+// LLVM:   store ptr %[[TEMP_SLOT]], ptr %[[Y_ADDR]]
+// LLVM:   %[[Y_REF:.*]] = load ptr, ptr %[[Y_ADDR]]
+// LLVM:   %[[Y_VALUE:.*]] = load i32, ptr %[[Y_REF]]
+// LLVM:   store i32 %[[Y_VALUE]], ptr %[[X]]
+
+// OGCG: define {{.*}} i32 @_Z11test_scopedv()
+// OGCG:   %[[X:.*]] = alloca i32
+// OGCG:   %[[Y_ADDR:.*]] = alloca ptr
+// OGCG:   %[[TEMP_SLOT:.*]] = alloca i32
+// OGCG:   %[[TEMP_VALUE1:.*]] = call noundef i32 @_Z8make_intv()
+// OGCG:   store i32 %[[TEMP_VALUE1]], ptr %[[X]]
+// OGCG:   %[[TEMP_VALUE2:.*]] = call noundef i32 @_Z8make_intv()
+// OGCG:   store i32 %[[TEMP_VALUE2]], ptr %[[TEMP_SLOT]]
+// OGCG:   store ptr %[[TEMP_SLOT]], ptr %[[Y_ADDR]]
+// OGCG:   %[[Y_REF:.*]] = load ptr, ptr %[[Y_ADDR]]
+// OGCG:   %[[Y_VALUE:.*]] = load i32, ptr %[[Y_REF]]
+// OGCG:   store i32 %[[Y_VALUE]], ptr %[[X]]