[CIR] Add support for string literal lvalues in ConstantLValueEmitter (#154514)

Author: mmha

clang/lib/CIR/CodeGen/CIRGenExprConstant.cpp

@@ -578,8 +578,7 @@ ConstantLValueEmitter::VisitCompoundLiteralExpr(const CompoundLiteralExpr *e) {
 
 ConstantLValue
 ConstantLValueEmitter::VisitStringLiteral(const StringLiteral *e) {
-  cgm.errorNYI(e->getSourceRange(), "ConstantLValueEmitter: string literal");
-  return {};
+  return cgm.getAddrOfConstantStringFromLiteral(e);
 }
 
 ConstantLValue

clang/lib/CIR/CodeGen/CIRGenModule.cpp

@@ -1318,6 +1318,19 @@ cir::GlobalOp CIRGenModule::getGlobalForStringLiteral(const StringLiteral *s,
   return gv;
 }
 
+/// Return a pointer to a constant array for the given string literal.
+cir::GlobalViewAttr
+CIRGenModule::getAddrOfConstantStringFromLiteral(const StringLiteral *s,
+                                                 StringRef name) {
+  cir::GlobalOp gv = getGlobalForStringLiteral(s, name);
+  auto arrayTy = mlir::dyn_cast<cir::ArrayType>(gv.getSymType());
+  assert(arrayTy && "String literal must be array");
+  assert(!cir::MissingFeatures::addressSpace());
+  cir::PointerType ptrTy = getBuilder().getPointerTo(arrayTy.getElementType());
+
+  return builder.getGlobalViewAttr(ptrTy, gv);
+}
+
 void CIRGenModule::emitExplicitCastExprType(const ExplicitCastExpr *e,
                                             CIRGenFunction *cgf) {
   if (cgf && e->getType()->isVariablyModifiedType())

clang/lib/CIR/CodeGen/CIRGenModule.h

@@ -198,6 +198,12 @@ class CIRGenModule : public CIRGenTypeCache {
   cir::GlobalOp getGlobalForStringLiteral(const StringLiteral *s,
                                           llvm::StringRef name = ".str");
 
+  /// Return a global symbol reference to a constant array for the given string
+  /// literal.
+  cir::GlobalViewAttr
+  getAddrOfConstantStringFromLiteral(const StringLiteral *s,
+                                     llvm::StringRef name = ".str");
+
   /// Set attributes which are common to any form of a global definition (alias,
   /// Objective-C method, function, global variable).
   ///

clang/test/CIR/CodeGen/string-literals.cpp

@@ -5,19 +5,45 @@
 // RUN: %clang_cc1 -triple aarch64-none-linux-android21 -emit-llvm %s -o %t.ll
 // RUN: FileCheck --check-prefix=OGCG --input-file=%t.ll %s
 
-// CIR: cir.global "private" constant cir_private dso_local @[[STR1_GLOBAL:.*]] = #cir.const_array<"abcd\00" : !cir.array<!s8i x 5>> : !cir.array<!s8i x 5>
 
-// LLVM: @[[STR1_GLOBAL:.*]] = private constant [5 x i8] c"abcd\00"
+char const *array[] {
+    "my", "hands", "are", "typing", "words"
+};
 
-// OGCG: @[[STR1_GLOBAL:.*]] = private unnamed_addr constant [5 x i8] c"abcd\00"
+// CIR: cir.global "private" constant cir_private dso_local @"[[STR:.+]]" = #cir.const_array<"my\00" : !cir.array<!s8i x 3>> : !cir.array<!s8i x 3>
+// CIR: cir.global "private" constant cir_private dso_local @"[[STR1:.+]]" = #cir.const_array<"hands\00" : !cir.array<!s8i x 6>> : !cir.array<!s8i x 6>
+// CIR: cir.global "private" constant cir_private dso_local @"[[STR2:.+]]" = #cir.const_array<"are\00" : !cir.array<!s8i x 4>> : !cir.array<!s8i x 4>
+// CIR: cir.global "private" constant cir_private dso_local @"[[STR3:.+]]" = #cir.const_array<"typing\00" : !cir.array<!s8i x 7>> : !cir.array<!s8i x 7>
+// CIR: cir.global "private" constant cir_private dso_local @"[[STR4:.+]]" = #cir.const_array<"words\00" : !cir.array<!s8i x 6>> : !cir.array<!s8i x 6>
+// CIR: cir.global external @array = #cir.const_array<[#cir.global_view<@"[[STR]]"> : !cir.ptr<!s8i>, #cir.global_view<@"[[STR1]]"> : !cir.ptr<!s8i>, #cir.global_view<@"[[STR2]]"> : !cir.ptr<!s8i>, #cir.global_view<@"[[STR3]]"> : !cir.ptr<!s8i>, #cir.global_view<@"[[STR4]]"> : !cir.ptr<!s8i>]> : !cir.array<!cir.ptr<!s8i> x 5>
+
+// LLVM: @[[STR:.+]] = private constant [3 x i8] c"my\00"
+// LLVM: @[[STR1:.+]] = private constant [6 x i8] c"hands\00"
+// LLVM: @[[STR2:.+]] = private constant [4 x i8] c"are\00"
+// LLVM: @[[STR3:.+]] = private constant [7 x i8] c"typing\00"
+// LLVM: @[[STR4:.+]] = private constant [6 x i8] c"words\00"
+// LLVM: @array = global [5 x ptr] [ptr @[[STR]], ptr @[[STR1]], ptr @[[STR2]], ptr @[[STR3]], ptr @[[STR4]]]
+
+// OGCG: @[[STR:.+]] = private unnamed_addr constant [3 x i8] c"my\00"
+// OGCG: @[[STR1:.+]] = private unnamed_addr constant [6 x i8] c"hands\00"
+// OGCG: @[[STR2:.+]] = private unnamed_addr constant [4 x i8] c"are\00"
+// OGCG: @[[STR3:.+]] = private unnamed_addr constant [7 x i8] c"typing\00"
+// OGCG: @[[STR4:.+]] = private unnamed_addr constant [6 x i8] c"words\00"
+// OGCG: @array = global [5 x ptr] [ptr @[[STR]], ptr @[[STR1]], ptr @[[STR2]], ptr @[[STR3]], ptr @[[STR4]]]
+
+// CIR: cir.global "private" constant cir_private dso_local @[[STR5_GLOBAL:.*]] = #cir.const_array<"abcd\00" : !cir.array<!s8i x 5>> : !cir.array<!s8i x 5>
+
+// LLVM: @[[STR5_GLOBAL:.*]] = private constant [5 x i8] c"abcd\00"
+
+// OGCG: @[[STR5_GLOBAL:.*]] = private unnamed_addr constant [5 x i8] c"abcd\00"
 
 decltype(auto) returns_literal() {
     return "abcd";
 }
 
 // CIR: cir.func{{.*}} @_Z15returns_literalv() -> !cir.ptr<!cir.array<!s8i x 5>>
 // CIR:   %[[RET_ADDR:.*]] = cir.alloca !cir.ptr<!cir.array<!s8i x 5>>, !cir.ptr<!cir.ptr<!cir.array<!s8i x 5>>>, ["__retval"]
-// CIR:   %[[STR_ADDR:.*]] = cir.get_global @[[STR1_GLOBAL]] : !cir.ptr<!cir.array<!s8i x 5>>
+// CIR:   %[[STR_ADDR:.*]] = cir.get_global @[[STR5_GLOBAL]] : !cir.ptr<!cir.array<!s8i x 5>>
 // CIR:   cir.store{{.*}} %[[STR_ADDR]], %[[RET_ADDR]]
 // CIR:   %[[RET:.*]] = cir.load %[[RET_ADDR]]
 // CIR:   cir.return %[[RET]]