[flang] Correctly handle -mframe-pointer=reserved (#146937)

Fixes `#146802`

#146582 started using the `Reserved` Frame Pointer kind for Arm64
Windows, but this revealed a bug in Flang where it copied the
`-mframe-pointer=reserved` flag from Clang, but didn't correctly handle
it in its own command line parser and subsequent compilation pipeline.

This change adds support for `-mframe-pointer=reserved` and adds a test
to make sure that functions are correctly marked when the flag is set.

Author: dpaoliello

flang/lib/Frontend/CompilerInvocation.cpp

@@ -291,13 +291,14 @@ static void parseCodeGenArgs(Fortran::frontend::CodeGenOptions &opts,
 
   opts.AliasAnalysis = opts.OptimizationLevel > 0;
 
-  // -mframe-pointer=none/non-leaf/all option.
+  // -mframe-pointer=none/non-leaf/reserved/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("reserved", llvm::FramePointerKind::Reserved)
             .Case("all", llvm::FramePointerKind::All)
             .Default(std::nullopt);
 

flang/lib/Optimizer/Passes/Pipelines.cpp

@@ -358,6 +358,8 @@ void createDefaultFIRCodeGenPassPipeline(mlir::PassManager &pm,
     framePointerKind = mlir::LLVM::framePointerKind::FramePointerKind::NonLeaf;
   else if (config.FramePointerKind == llvm::FramePointerKind::All)
     framePointerKind = mlir::LLVM::framePointerKind::FramePointerKind::All;
+  else if (config.FramePointerKind == llvm::FramePointerKind::Reserved)
+    framePointerKind = mlir::LLVM::framePointerKind::FramePointerKind::Reserved;
   else
     framePointerKind = mlir::LLVM::framePointerKind::FramePointerKind::None;
 

flang/test/Driver/func-attr.f90

@@ -4,6 +4,7 @@
 
 ! 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=reserved -emit-llvm -o - %s 2>&1| FileCheck %s --check-prefix=CHECK-RESERVEDFP
 ! 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
 
@@ -20,6 +21,7 @@ end subroutine func
 
 ! CHECK-NONEFP-NOT: attributes #0 = { "frame-pointer"="{{.*}}" }
 ! CHECK-NONLEAFFP: attributes #0 = { "frame-pointer"="non-leaf" }
+! CHECK-RESERVEDFP: attributes #0 = { "frame-pointer"="reserved" }
 ! CHECK-ALLFP: attributes #0 = { "frame-pointer"="all" }
 
 ! CHECK-WRONGVALUEFP:error: invalid value 'wrongval' in '-mframe-pointer=wrongval'