[flang] Pass to add frame pointer attribute

flang/include/flang/Frontend/CodeGenOptions.def

@@ -38,6 +38,7 @@ CODEGENOPT(Underscoring, 1, 1)
 ENUM_CODEGENOPT(RelocationModel, llvm::Reloc::Model, 3, llvm::Reloc::PIC_) ///< Name of the relocation model to use.
 ENUM_CODEGENOPT(DebugInfo,  llvm::codegenoptions::DebugInfoKind, 4,  llvm::codegenoptions::NoDebugInfo) ///< Level of debug info to generate
 ENUM_CODEGENOPT(VecLib, llvm::driver::VectorLibrary, 3, llvm::driver::VectorLibrary::NoLibrary) ///< Vector functions library to use
+ENUM_CODEGENOPT(FramePointer, llvm::FramePointerKind, 2, llvm::FramePointerKind::None) ///< Enable the usage of frame pointers
 
 #undef CODEGENOPT
 #undef ENUM_CODEGENOPT

flang/include/flang/Optimizer/Transforms/Passes.h

@@ -10,6 +10,7 @@
 #define FORTRAN_OPTIMIZER_TRANSFORMS_PASSES_H
 
 #include "flang/Optimizer/Dialect/FIROps.h"
+#include "mlir/Dialect/LLVMIR/LLVMAttrs.h"
 #include "mlir/Pass/Pass.h"
 #include "mlir/Pass/PassRegistry.h"
 #include <memory>
@@ -83,6 +84,15 @@ std::unique_ptr<mlir::Pass> createVScaleAttrPass();
 std::unique_ptr<mlir::Pass>
 createVScaleAttrPass(std::pair<unsigned, unsigned> vscaleAttr);
 
+struct FunctionAttrTypes {
+  mlir::LLVM::framePointerKind::FramePointerKind framePointerKind =
+      mlir::LLVM::framePointerKind::FramePointerKind::None;
+};
+
+std::unique_ptr<mlir::Pass> createFunctionAttrPass();
+std::unique_ptr<mlir::Pass>
+createFunctionAttrPass(FunctionAttrTypes &functionAttr);
+
 // declarative passes
 #define GEN_PASS_REGISTRATION
 #include "flang/Optimizer/Transforms/Passes.h.inc"

flang/include/flang/Optimizer/Transforms/Passes.td

@@ -349,4 +349,25 @@ def VScaleAttr : Pass<"vscale-attr", "mlir::func::FuncOp"> {
   let constructor = "::fir::createVScaleAttrPass()";
 }
 
+def FunctionAttr : Pass<"function-attr", "mlir::func::FuncOp"> {
+  let summary = "Pass that adds function attributes expected at LLVM IR level";
+  let description = [{ This feature introduces a general attribute aimed at
+     customizing function characteristics. 
+     Options include:
+     Add "frame-pointer" attribute to functions: Set an attribute for the frame 
+     pointer on functions, to avoid saving the frame pointer in a register in 
+     functions where it is unnecessary. This eliminates the need for
+     instructions to save, establish, and restore frame pointers, while also
+     freeing up an additional register in numerous functions. However, this
+     approach can make debugging unfeasible on certain machines.
+  }];
+  let options = [
+    Option<"framePointerKind", "frame-pointer",
+           "mlir::LLVM::framePointerKind::FramePointerKind", 
+           /*default=*/"mlir::LLVM::framePointerKind::FramePointerKind{}",
+           "frame pointer">,
+  ];
+  let constructor = "::fir::createFunctionAttrPass()";
+}
+
 #endif // FLANG_OPTIMIZER_TRANSFORMS_PASSES

flang/include/flang/Tools/CLOptions.inc

@@ -10,6 +10,7 @@
 /// debugging the test tools. This file must be included into the tool.
 
 #include "mlir/Conversion/SCFToControlFlow/SCFToControlFlow.h"
+#include "mlir/Dialect/LLVMIR/LLVMAttrs.h"
 #include "mlir/Pass/PassManager.h"
 #include "mlir/Transforms/GreedyPatternRewriteDriver.h"
 #include "mlir/Transforms/Passes.h"
@@ -311,6 +312,20 @@ inline void createDefaultFIRCodeGenPassPipeline(
   if (config.VScaleMin != 0)
     pm.addPass(fir::createVScaleAttrPass({config.VScaleMin, config.VScaleMax}));
 
+  // Add function attributes
+  fir::FunctionAttrTypes functionAttrs;
+
+  if (config.FramePointerKind != llvm::FramePointerKind::None) {
+    if (config.FramePointerKind == llvm::FramePointerKind::NonLeaf)
+      functionAttrs.framePointerKind =
+          mlir::LLVM::framePointerKind::FramePointerKind::NonLeaf;
+    else
+      functionAttrs.framePointerKind =
+          mlir::LLVM::framePointerKind::FramePointerKind::All;
+
+    pm.addPass(fir::createFunctionAttrPass(functionAttrs));
+  }
+
   fir::addFIRToLLVMPass(pm, config);
 }
 

flang/include/flang/Tools/CrossToolHelpers.h

@@ -35,6 +35,7 @@ struct MLIRToLLVMPassPipelineConfig {
     LoopVersioning = opts.LoopVersioning;
     DebugInfo = opts.getDebugInfo();
     AliasAnalysis = opts.AliasAnalysis;
+    FramePointerKind = opts.getFramePointer();
   }
 
   llvm::OptimizationLevel OptLevel; ///< optimisation level
@@ -44,6 +45,8 @@ struct MLIRToLLVMPassPipelineConfig {
   bool AliasAnalysis = false; ///< Add TBAA tags to generated LLVMIR
   llvm::codegenoptions::DebugInfoKind DebugInfo =
       llvm::codegenoptions::NoDebugInfo; ///< Debug info generation.
+  llvm::FramePointerKind FramePointerKind =
+      llvm::FramePointerKind::None; ///< Add frame pointer to functions.
   unsigned VScaleMin = 0; ///< SVE vector range minimum.
   unsigned VScaleMax = 0; ///< SVE vector range maximum.
 };

flang/lib/Frontend/CompilerInvocation.cpp

@@ -245,6 +245,23 @@ static void parseCodeGenArgs(Fortran::frontend::CodeGenOptions &opts,
 
   opts.AliasAnalysis = opts.OptimizationLevel > 0;
 
+  // -mframe-pointer=none/non-leaf/all option.
+  if (const llvm::opt::Arg *a =
+          args.getLastArg(clang::driver::options::OPT_mframe_pointer_EQ)) {
+    std::optional<llvm::FramePointerKind> val =
+        llvm::StringSwitch<std::optional<llvm::FramePointerKind>>(a->getValue())
+            .Case("none", llvm::FramePointerKind::None)
+            .Case("non-leaf", llvm::FramePointerKind::NonLeaf)
+            .Case("all", llvm::FramePointerKind::All)
+            .Default(std::nullopt);
+
+    if (!val.has_value()) {
+      diags.Report(clang::diag::err_drv_invalid_value)
+          << a->getAsString(args) << a->getValue();
+    } else
+      opts.setFramePointer(val.value());
+  }
+
   for (auto *a : args.filtered(clang::driver::options::OPT_fpass_plugin_EQ))
     opts.LLVMPassPlugins.push_back(a->getValue());
 

flang/lib/Optimizer/Transforms/CMakeLists.txt

@@ -20,6 +20,7 @@ add_flang_library(FIRTransforms
   OMPFunctionFiltering.cpp
   OMPMarkDeclareTarget.cpp
   VScaleAttr.cpp
+  FunctionAttr.cpp
 
   DEPENDS
   FIRDialect

flang/lib/Optimizer/Transforms/FunctionAttr.cpp

@@ -0,0 +1,62 @@
+//===- FunctionAttr.cpp ---------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+//===----------------------------------------------------------------------===//
+/// \file
+/// This is a generic pass for adding attributes to functions.
+//===----------------------------------------------------------------------===//
+#include "flang/Optimizer/Transforms/Passes.h"
+#include "mlir/Dialect/LLVMIR/LLVMAttrs.h"
+
+namespace fir {
+#define GEN_PASS_DECL_FUNCTIONATTR
+#define GEN_PASS_DEF_FUNCTIONATTR
+#include "flang/Optimizer/Transforms/Passes.h.inc"
+} // namespace fir
+
+#define DEBUG_TYPE "func-attr"
+
+namespace {
+
+class FunctionAttrPass : public fir::impl::FunctionAttrBase<FunctionAttrPass> {
+public:
+  FunctionAttrPass(const fir::FunctionAttrOptions &options) {
+    framePointerKind = options.framePointerKind;
+  }
+  FunctionAttrPass() {}
+  void runOnOperation() override;
+};
+
+} // namespace
+
+void FunctionAttrPass::runOnOperation() {
+  LLVM_DEBUG(llvm::dbgs() << "=== Begin " DEBUG_TYPE " ===\n");
+  mlir::func::FuncOp func = getOperation();
+
+  LLVM_DEBUG(llvm::dbgs() << "Func-name:" << func.getSymName() << "\n");
+
+  mlir::MLIRContext *context = &getContext();
+  if (framePointerKind != mlir::LLVM::framePointerKind::FramePointerKind::None)
+    func->setAttr("frame_pointer", mlir::LLVM::FramePointerKindAttr::get(
+                                       context, framePointerKind));
+
+  LLVM_DEBUG(llvm::dbgs() << "=== End " DEBUG_TYPE " ===\n");
+}
+
+std::unique_ptr<mlir::Pass>
+fir::createFunctionAttrPass(fir::FunctionAttrTypes &functionAttr) {
+  FunctionAttrOptions opts;
+  // Frame pointer
+  opts.framePointerKind = functionAttr.framePointerKind;
+
+  return std::make_unique<FunctionAttrPass>(opts);
+}
+
+std::unique_ptr<mlir::Pass> fir::createFunctionAttrPass() {
+  return std::make_unique<FunctionAttrPass>();
+}

flang/test/Driver/frame-pointer-forwarding.f90

@@ -1,9 +1,12 @@
 ! Test that flang-new forwards -fno-omit-frame-pointer and -fomit-frame-pointer Flang frontend
-! RUN: %flang -fno-omit-frame-pointer --target=x86-none-none -fsyntax-only -### %s -o %t 2>&1  | FileCheck %s
-! CHECK: "-mframe-pointer=all"
+! RUN: %flang --target=aarch64-none-none -fsyntax-only -### %s -o %t 2>&1  | FileCheck %s --check-prefix=CHECK-NOVALUE
+! CHECK-NOVALUE: "-fc1"{{.*}}"-mframe-pointer=non-leaf"
+
+! RUN: %flang -fomit-frame-pointer --target=aarch64-none-none -fsyntax-only -### %s -o %t 2>&1  | FileCheck %s --check-prefix=CHECK-NONEFP
+! CHECK-NONEFP: "-fc1"{{.*}}"-mframe-pointer=none"
 
 ! RUN: %flang -fno-omit-frame-pointer --target=aarch64-none-none -fsyntax-only -### %s -o %t 2>&1  | FileCheck %s --check-prefix=CHECK-NONLEAFFP
-! CHECK-NONLEAFFP: "-mframe-pointer=non-leaf"
+! CHECK-NONLEAFFP: "-fc1"{{.*}}"-mframe-pointer=non-leaf"
 
-! RUN: %flang -fomit-frame-pointer --target=aarch64-none-none -fsyntax-only -### %s -o %t 2>&1  | FileCheck %s --check-prefix=CHECK-NONEFP
-! CHECK-NONEFP: "-mframe-pointer=none"
+! RUN: %flang -fno-omit-frame-pointer --target=x86-none-none -fsyntax-only -### %s -o %t 2>&1  | FileCheck %s --check-prefix=CHECK-ALLFP
+! CHECK-ALLFP: "-fc1"{{.*}}"-mframe-pointer=all"

flang/test/Driver/func-attr.f90

@@ -0,0 +1,23 @@
+! Test that -mframe-pointer can accept only specific values and when given an invalid value, check it raises an error.
+
+! RUN: %flang_fc1 -triple aarch64-none-none -mframe-pointer=none -emit-llvm -o - %s 2>&1| FileCheck %s --check-prefix=CHECK-NONEFP
+! RUN: %flang_fc1 -triple aarch64-none-none -mframe-pointer=non-leaf -emit-llvm -o - %s 2>&1| FileCheck %s --check-prefix=CHECK-NONLEAFFP
+! RUN: %flang_fc1 -triple aarch64-none-none -mframe-pointer=all -emit-llvm -o - %s 2>&1| FileCheck %s --check-prefix=CHECK-ALLFP
+! RUN: not %flang_fc1 -triple aarch64-none-none -mframe-pointer=wrongval -emit-llvm -o - %s 2>&1| FileCheck %s --check-prefix=CHECK-WRONGVALUEFP
+
+! CHECK-NONEFP-LABEL: @func_() {
+
+! CHECK-NONLEAFFP-LABEL: @func_()
+! CHECK-NONLEAFFP-SAME: #0
+
+! CHECK-ALLFP-LABEL: @func_()
+! CHECK-ALLFP-SAME: #0
+
+subroutine func
+end subroutine func
+
+! CHECK-NONEFP-NOT: attributes #0 = { "frame-pointer"="{{.*}}" }
+! CHECK-NONLEAFFP: attributes #0 = { "frame-pointer"="non-leaf" }
+! CHECK-ALLFP: attributes #0 = { "frame-pointer"="all" }
+
+! CHECK-WRONGVALUEFP:error: invalid value 'wrongval' in '-mframe-pointer=wrongval'

flang/test/Driver/mlir-debug-pass-pipeline.f90

@@ -82,5 +82,5 @@
 ! ALL-NEXT: ExternalNameConversion
 ! DEBUG-NEXT: AddDebugFoundation
 ! NO-DEBUG-NOT: AddDebugFoundation
-! ALL-NEXT: FIRToLLVMLowering
+! ALL: FIRToLLVMLowering
 ! ALL-NOT: LLVMIRLoweringPass

flang/test/Driver/save-mlir-temps.f90

@@ -51,9 +51,9 @@
 ! Content to check from the MLIR outputs
 !--------------------------
 ! MLIR-FIR-NOT: llvm.func
-! MLIR-FIR: func.func @{{.*}}main() {
+! MLIR-FIR: func.func @{{.*}}main(){{.*}}{
 
 ! MLIR-FIR-NOT: func.func
-! MLIR-LLVMIR: llvm.func @{{.*}}main() {
+! MLIR-LLVMIR: llvm.func @{{.*}}main(){{.*}}{
 
 end program

flang/test/Fir/box-offset-codegen.fir

@@ -7,7 +7,7 @@ func.func @scalar_addr(%scalar : !fir.ref<!fir.box<!fir.type<t>>>) -> !fir.llvm_
   return %addr : !fir.llvm_ptr<!fir.ref<!fir.type<t>>>
 }
 // CHECK-LABEL: define ptr @scalar_addr(
-// CHECK-SAME: ptr %[[BOX:.*]]) {
+// CHECK-SAME: ptr %[[BOX:.*]]){{.*}}{
 // CHECK:    %[[VAL_0:.*]] = getelementptr { ptr, i64, i32, i8, i8, i8, i8, ptr, [1 x i64] }, ptr %[[BOX]], i32 0, i32 0
 // CHECK:    ret ptr %[[VAL_0]]
 
@@ -16,7 +16,7 @@ func.func @scalar_tdesc(%scalar : !fir.ref<!fir.box<!fir.type<t>>>) -> !fir.llvm
   return %tdesc : !fir.llvm_ptr<!fir.tdesc<!fir.type<t>>>
 }
 // CHECK-LABEL: define ptr @scalar_tdesc(
-// CHECK-SAME: ptr %[[BOX:.*]]) {
+// CHECK-SAME: ptr %[[BOX:.*]]){{.*}}{
 // CHECK:    %[[VAL_0:.*]] = getelementptr { ptr, i64, i32, i8, i8, i8, i8, ptr, [1 x i64] }, ptr %[[BOX]], i32 0, i32 7
 // CHECK:    ret ptr %[[VAL_0]]
 
@@ -25,7 +25,7 @@ func.func @array_addr(%array : !fir.ref<!fir.class<!fir.ptr<!fir.array<?x!fir.ty
   return %addr : !fir.llvm_ptr<!fir.ptr<!fir.array<?x!fir.type<t>>>>
 }
 // CHECK-LABEL: define ptr @array_addr(
-// CHECK-SAME: ptr %[[BOX:.*]]) {
+// CHECK-SAME: ptr %[[BOX:.*]]){{.*}}{
 // CHECK:    %[[VAL_0:.*]] = getelementptr { ptr, i64, i32, i8, i8, i8, i8, [1 x [3 x i64]], ptr, [1 x i64] }, ptr %[[BOX]], i32 0, i32 0
 // CHECK:    ret ptr %[[VAL_0]]
 
@@ -34,6 +34,6 @@ func.func @array_tdesc(%array : !fir.ref<!fir.class<!fir.ptr<!fir.array<?x!fir.t
   return %tdesc : !fir.llvm_ptr<!fir.tdesc<!fir.type<t>>>
 }
 // CHECK-LABEL: define ptr @array_tdesc(
-// CHECK-SAME: ptr %[[BOX:.*]]) {
+// CHECK-SAME: ptr %[[BOX:.*]]){{.*}}{
 // CHECK:    %[[VAL_0:.*]] = getelementptr { ptr, i64, i32, i8, i8, i8, i8, [1 x [3 x i64]], ptr, [1 x i64] }, ptr %[[BOX]], i32 0, i32 8
 // CHECK:    ret ptr %[[VAL_0]]

flang/test/Fir/polymorphic.fir

@@ -10,7 +10,7 @@ func.func @_QMpolymorphic_testPtest_allocate_unlimited_polymorphic_non_derived()
   return
 }
 
-// CHECK-LABEL: define void @_QMpolymorphic_testPtest_allocate_unlimited_polymorphic_non_derived() {
+// CHECK-LABEL: define void @_QMpolymorphic_testPtest_allocate_unlimited_polymorphic_non_derived(){{.*}}{
 // CHECK:   %[[MEM:.*]] = alloca { ptr, i64, i32, i8, i8, i8, i8, ptr, [1 x i64] }
 // CHECK:   %[[DESC:.*]] = alloca { ptr, i64, i32, i8, i8, i8, i8, ptr, [1 x i64] }, i64 1
 // CHECK:   store { ptr, i64, i32, i8, i8, i8, i8, ptr, [1 x i64] } { ptr null, i64 0, i32 20180515, i8 0, i8 -1, i8 1, i8 1, ptr null, [1 x i64] undef }, ptr %[[MEM]]
@@ -87,7 +87,7 @@ func.func @_QMunlimitedPsub1(%arg0: !fir.class<!fir.array<?xnone>> {fir.bindc_na
 }
 
 // CHECK-LABEL: define void @_QMunlimitedPsub1(
-// CHECK-SAME: ptr %[[ARRAY:.*]]) {
+// CHECK-SAME: ptr %[[ARRAY:.*]]){{.*}}{
 // CHECK: %[[BOX:.*]] = alloca { ptr, i64, i32, i8, i8, i8, i8, ptr, [1 x i64] }
 // CHECK: %{{.}} = getelementptr { ptr, i64, i32, i8, i8, i8, i8, [1 x [3 x i64]], ptr, [1 x i64] }, ptr %[[ARRAY]], i32 0, i32 7, i32 0, i32 2
 // CHECK: %[[TYPE_DESC_GEP:.*]] = getelementptr { ptr, i64, i32, i8, i8, i8, i8, [1 x [3 x i64]], ptr, [1 x i64] }, ptr %[[ARRAY]], i32 0, i32 8
@@ -151,7 +151,7 @@ func.func @_QQmain() {
   return
 }
 
-// CHECK-LABEL: define void @_QQmain() {
+// CHECK-LABEL: define void @_QQmain(){{.*}}{
 // CHECK: %[[CLASS_NONE:.*]] = alloca { ptr, i64, i32, i8, i8, i8, i8, ptr, [1 x i64] }
 // CHECK: %[[DESC:.*]] = alloca { ptr, i64, i32, i8, i8, i8, i8, ptr, [1 x i64] }, i64 1
 // CHECK: store { ptr, i64, i32, i8, i8, i8, i8, ptr, [1 x i64] } { ptr @_QMmod1Ea, i64 ptrtoint (ptr getelementptr (%_QMmod1TtK2, ptr null, i32 1) to i64), i32 20180515, i8 0, i8 42, i8 1, i8 1, ptr @_QMmod1E.dt.t.2, [1 x i64] undef }, ptr %[[CLASS_NONE]], align 8
@@ -175,7 +175,7 @@ func.func @_QMmod2Pinitp(%arg0: !fir.ref<!fir.class<!fir.ptr<none>>> {fir.bindc_
 func.func private @_FortranAPointerAssociate(!fir.ref<!fir.box<none>>, !fir.box<none>) -> none attributes {fir.runtime}
 
 // CHECK-LABEL: define void @_QMmod2Pinitp(
-// CHECK-SAME: ptr %[[ARG0:.*]]) {
+// CHECK-SAME: ptr %[[ARG0:.*]]){{.*}}{
 // CHECK: %[[ALLOCA_CLASS_NONE:.*]] = alloca { ptr, i64, i32, i8, i8, i8, i8, ptr, [1 x i64] }
 // CHECK: %[[LOAD:.*]] = load { ptr, i64, i32, i8, i8, i8, i8, ptr, [1 x i64] }, ptr %[[ARG0]]
 // CHECK: store { ptr, i64, i32, i8, i8, i8, i8, ptr, [1 x i64] } %[[LOAD]], ptr %[[ALLOCA_CLASS_NONE]]

flang/test/Fir/tbaa-codegen.fir

@@ -28,7 +28,7 @@ module attributes {fir.defaultkind = "a1c4d8i4l4r4", fir.kindmap = "", llvm.targ
 }
 
 // CHECK-LABEL: define void @_QPsimple(
-// CHECK-SAME:      ptr %[[ARG0:.*]]) {
+// CHECK-SAME:      ptr %[[ARG0:.*]]){{.*}}{
 // [...]
 // load  a(2):
 // CHECK:  %[[VAL20:.*]] = getelementptr i8, ptr %{{.*}}, i64 %{{.*}}

flang/test/Fir/tbaa-codegen2.fir

@@ -60,7 +60,7 @@ module attributes {fir.defaultkind = "a1c4d8i4l4r4", fir.kindmap = "", llvm.targ
   }
 }
 // CHECK-LABEL: define void @_QPfunc(
-// CHECK-SAME:      ptr %[[ARG0:.*]]) {
+// CHECK-SAME:      ptr %[[ARG0:.*]]){{.*}}{
 // [...]
 // CHECK:  %[[VAL5:.*]] = getelementptr { ptr, i64, i32, i8, i8, i8, i8, [1 x [3 x i64]] }, ptr %[[ARG0]], i32 0, i32 7, i32 0, i32 0
 // box access: