[CIR][CIRGen][Builtin] Support __builtin_frame_address (#1137)

Author: ghehg

clang/include/clang/CIR/Dialect/IR/CIROps.td

@@ -4227,13 +4227,21 @@ def MemChrOp : CIR_Op<"libc.memchr"> {
 }
 
 //===----------------------------------------------------------------------===//
-// ReturnAddrOp
+// ReturnAddrOp and FrameAddrOp
 //===----------------------------------------------------------------------===//
 
-def ReturnAddrOp : CIR_Op<"return_address"> {
+class FuncAddrBuiltinOp<string mnemonic> : CIR_Op<mnemonic, []> {
   let arguments = (ins UInt32:$level);
-  let summary = "The return address of the current function, or of one of its callers";
   let results = (outs Res<VoidPtr, "">:$result);
+  let assemblyFormat = [{
+    `(` $level `)` attr-dict
+  }];
+  let hasVerifier = 0;
+}
+
+def ReturnAddrOp : FuncAddrBuiltinOp<"return_address"> {
+  let summary =
+      "The return address of the current function, or of one of its callers";
 
   let description = [{
     Represents call to builtin function ` __builtin_return_address` in CIR.
@@ -4250,11 +4258,34 @@ def ReturnAddrOp : CIR_Op<"return_address"> {
     %p = return_address(%level) -> !cir.ptr<!void>
     ```
   }];
+}
 
-  let assemblyFormat = [{
-    `(` $level `)` attr-dict
+def FrameAddrOp : FuncAddrBuiltinOp<"frame_address"> {
+  let summary =
+      "The frame address of the current function, or of one of its callers";
+
+  let description = [{
+    Represents call to builtin function ` __builtin_frame_address` in CIR.
+    This builtin function returns the frame address of the current function,
+    or of one of its callers. The frame is the area on the stack that holds
+    local variables and saved registers. The frame address is normally the
+    address of the first word pushed on to the stack by the function.
+    However, the exact definition depends upon the processor and the calling
+    convention. If the processor has a dedicated frame pointer register, and
+    the function has a frame, then __builtin_frame_address returns the value of
+    the frame pointer register.
+
+    The `level` argument is number of frames to scan up the call stack.
+    For instance, value of 0 yields the frame address of the current function,
+    value of 1 yields the frame address of the caller of the current function,
+    and so forth.
+
+    Examples:
+
+    ```mlir
+    %p = frame_address(%level) -> !cir.ptr<!void>
+    ```
   }];
-  let hasVerifier = 0;
 }
 
 //===----------------------------------------------------------------------===//

clang/lib/CIR/CodeGen/CIRGenBuiltin.cpp

@@ -1592,18 +1592,21 @@ RValue CIRGenFunction::emitBuiltinExpr(const GlobalDecl GD, unsigned BuiltinID,
     llvm_unreachable("BI__builtin_wmemcmp NYI");
   case Builtin::BI__builtin_dwarf_cfa:
     llvm_unreachable("BI__builtin_dwarf_cfa NYI");
-  case Builtin::BI__builtin_return_address: {
+  case Builtin::BI__builtin_return_address:
+  case Builtin::BI__builtin_frame_address: {
     mlir::Location loc = getLoc(E->getExprLoc());
     mlir::Attribute levelAttr = ConstantEmitter(*this).emitAbstract(
         E->getArg(0), E->getArg(0)->getType());
-    int64_t level = mlir::cast<cir::IntAttr>(levelAttr).getSInt();
+    uint64_t level = mlir::cast<cir::IntAttr>(levelAttr).getUInt();
+    if (BuiltinID == Builtin::BI__builtin_return_address) {
+      return RValue::get(builder.create<cir::ReturnAddrOp>(
+          loc, builder.getUInt32(level, loc)));
+    }
     return RValue::get(
-        builder.create<cir::ReturnAddrOp>(loc, builder.getUInt32(level, loc)));
+        builder.create<cir::FrameAddrOp>(loc, builder.getUInt32(level, loc)));
   }
   case Builtin::BI_ReturnAddress:
     llvm_unreachable("BI_ReturnAddress NYI");
-  case Builtin::BI__builtin_frame_address:
-    llvm_unreachable("BI__builtin_frame_address NYI");
   case Builtin::BI__builtin_extract_return_addr:
     llvm_unreachable("BI__builtin_extract_return_addr NYI");
   case Builtin::BI__builtin_frob_return_addr:

clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.cpp

@@ -3612,6 +3612,15 @@ mlir::LogicalResult CIRToLLVMReturnAddrOpLowering::matchAndRewrite(
   return mlir::success();
 }
 
+mlir::LogicalResult CIRToLLVMFrameAddrOpLowering::matchAndRewrite(
+    cir::FrameAddrOp op, OpAdaptor adaptor,
+    mlir::ConversionPatternRewriter &rewriter) const {
+  auto llvmPtrTy = mlir::LLVM::LLVMPointerType::get(rewriter.getContext());
+  replaceOpWithCallLLVMIntrinsicOp(rewriter, op, "llvm.frameaddress", llvmPtrTy,
+                                   adaptor.getOperands());
+  return mlir::success();
+}
+
 mlir::LogicalResult CIRToLLVMClearCacheOpLowering::matchAndRewrite(
     cir::ClearCacheOp op, OpAdaptor adaptor,
     mlir::ConversionPatternRewriter &rewriter) const {
@@ -3888,6 +3897,7 @@ void populateCIRToLLVMConversionPatterns(
       CIRToLLVMEhInflightOpLowering,
       CIRToLLVMEhTypeIdOpLowering,
       CIRToLLVMExpectOpLowering,
+      CIRToLLVMFrameAddrOpLowering,
       CIRToLLVMFreeExceptionOpLowering,
       CIRToLLVMFuncOpLowering,
       CIRToLLVMGetBitfieldOpLowering,

clang/lib/CIR/Lowering/DirectToLLVM/LowerToLLVM.h

@@ -936,6 +936,16 @@ class CIRToLLVMReturnAddrOpLowering
                   mlir::ConversionPatternRewriter &) const override;
 };
 
+class CIRToLLVMFrameAddrOpLowering
+    : public mlir::OpConversionPattern<cir::FrameAddrOp> {
+public:
+  using mlir::OpConversionPattern<cir::FrameAddrOp>::OpConversionPattern;
+
+  mlir::LogicalResult
+  matchAndRewrite(cir::FrameAddrOp op, OpAdaptor,
+                  mlir::ConversionPatternRewriter &) const override;
+};
+
 class CIRToLLVMClearCacheOpLowering
     : public mlir::OpConversionPattern<cir::ClearCacheOp> {
 public:

clang/test/CIR/CodeGen/builtins.cpp

@@ -100,9 +100,20 @@ extern "C" void *test_return_address(void) {
   return __builtin_return_address(1);
 
   // CIR-LABEL: test_return_address
-  // [[ARG:%.*]] = cir.const #cir.int<1> : !u32i
-  // {{%.*}} = cir.return_address([[ARG]])
+  // CIR: [[ARG:%.*]] = cir.const #cir.int<1> : !u32i
+  // CIR: {{%.*}} = cir.return_address([[ARG]])
 
   // LLVM-LABEL: @test_return_address
   // LLVM: {{%.*}} = call ptr @llvm.returnaddress(i32 1)
 }
+
+extern "C" void *test_frame_address(void) {
+  return __builtin_frame_address(1);
+
+  // CIR-LABEL: test_frame_address
+  // CIR: [[ARG:%.*]] = cir.const #cir.int<1> : !u32i
+  // CIR: {{%.*}} = cir.frame_address([[ARG]])
+
+  // LLVM-LABEL: @test_frame_address
+  // LLVM: {{%.*}} = call ptr @llvm.frameaddress.p0(i32 1)
+}

clang/test/CIR/IR/builtins.cir

@@ -5,10 +5,12 @@ module  {
   cir.func @test1() {
     %0 = cir.const #cir.int<1> : !u32i
     %1 = cir.return_address(%0)
+    %2 = cir.frame_address(%0)
     cir.return
   }
   // CHECK:  cir.func @test1()
   // CHECK:  %0 = cir.const #cir.int<1> : !u32i
   // CHECK:  %1 = cir.return_address(%0)
+  // CHECK:  %2 = cir.frame_address(%0)
   // CHECK: cir.return
 }