[Flang][Driver] Add support for fomit-frame-pointer 1/2

[victorkingi]

Summary

Mark the '-fomit-frame-pointer' as visible in the Flang Driver.

Note 1: This is just re-instating the previous behaviour that this flag is accepted by Flang but ignored.
Note 2: A subsequent patch will enable support for this flag in Flang by sharing code (after appropriate refactoring) with Clang.

[kiranchandramohan]

For our immediate purpose, I think changing the visibility in the Driver to include flang is sufficient. After that, we can spend time implementing this properly by refactoring the code to llvm.

llvm/include/llvm/Frontend/Driver/FramePointer.h

11 ↗

(On Diff #552322)

We should not include clang headers in llvm. We also should not refer to clang inside llvm.

[awarzynski]

Temporary fix for unknown argument error '-fomit-frame-pointer' when running flang tests

I don't follow - there's quite a lot going on here. More than the summary suggests.

[victorkingi]

In D158507#4606498, @awarzynski wrote:

Temporary fix for unknown argument error '-fomit-frame-pointer' when running flang tests

I don't follow - there's quite a lot going on here. More than the summary suggests.

Sorry about that, will be pushing a minimal version since what was needed for the fix was only an update to Options.td file

[victorkingi]

Minimalized patch to only have update to Options.td as well as
tests accompanying the change.

[victorkingi]

clang/include/clang/Driver/Options.td

7236–7240

This will be needed in the second patch when the flag functionality is added

[victorkingi]

This comment was removed by victorkingi.

[victorkingi]

revert addition of m64 visibility in Options.td

[victorkingi]

Removed mframe_pointer_eq update in Options.td, not required.

[victorkingi]

Moved function implementations from llvm directory to clang

clang/include/clang/Driver/Options.td

def fno_module_file_deps : Flag <["-"], "fno-module-file-deps">, Group<f_Group>,
   Flags<[NoXarchOption]>;
 def fno_ms_extensions : Flag<["-"], "fno-ms-extensions">, Group<f_Group>,
   Visibility<[ClangOption, CLOption]>;
 def fno_ms_compatibility : Flag<["-"], "fno-ms-compatibility">, Group<f_Group>,
   Visibility<[ClangOption, CLOption]>;
 def fno_objc_legacy_dispatch : Flag<["-"], "fno-objc-legacy-dispatch">, Group<f_Group>;
 def fno_objc_weak : Flag<["-"], "fno-objc-weak">, Group<f_Group>,
   Visibility<[ClangOption, CC1Option]>;
-def fno_omit_frame_pointer : Flag<["-"], "fno-omit-frame-pointer">, Group<f_Group>;
+def fno_omit_frame_pointer : Flag<["-"], "fno-omit-frame-pointer">, Group<f_Group>,
+  Visibility<[ClangOption, FlangOption]>;
 defm operator_names : BoolFOption<"operator-names",
   LangOpts<"CXXOperatorNames">, Default<cplusplus.KeyPath>,
   NegFlag<SetFalse, [], [ClangOption, CC1Option],
           "Do not treat C++ operator name keywords as synonyms for operators">,
   PosFlag<SetTrue>>;
 def fdiagnostics_absolute_paths : Flag<["-"], "fdiagnostics-absolute-paths">, Group<f_Group>,
   Visibility<[ClangOption, CC1Option, CLOption, DXCOption]>,
   HelpText<"Print absolute paths in diagnostics">,
def fobjc_disable_direct_methods_for_testing :
   MarshallingInfoFlag<LangOpts<"ObjCDisableDirectMethodsForTesting">>;
 defm objc_avoid_heapify_local_blocks : BoolFOption<"objc-avoid-heapify-local-blocks",
   CodeGenOpts<"ObjCAvoidHeapifyLocalBlocks">, DefaultFalse,
   PosFlag<SetTrue, [], [ClangOption], "Try">,
   NegFlag<SetFalse, [], [ClangOption], "Don't try">,
   BothFlags<[], [CC1Option], " to avoid heapifying local blocks">>;
 
 def fomit_frame_pointer : Flag<["-"], "fomit-frame-pointer">, Group<f_Group>,
+  Visibility<[ClangOption, FlangOption]>,
   HelpText<"Omit the frame pointer from functions that don't need it. "
   "Some stack unwinding cases, such as profilers and sanitizers, may prefer specifying -fno-omit-frame-pointer. "
   "On many targets, -O1 and higher omit the frame pointer by default. "
   "-m[no-]omit-leaf-frame-pointer takes precedence for leaf functions">;
 def fopenmp : Flag<["-"], "fopenmp">, Group<f_Group>,
   Flags<[NoArgumentUnused]>,
   Visibility<[ClangOption, CC1Option, FlangOption, FC1Option]>,
   HelpText<"Parse OpenMP pragmas and generate parallel code.">;

 def no_struct_path_tbaa : Flag<["-"], "no-struct-path-tbaa">,
   HelpText<"Turn off struct-path aware Type Based Alias Analysis">,
   MarshallingInfoNegativeFlag<CodeGenOpts<"StructPathTBAA">>;
 def new_struct_path_tbaa : Flag<["-"], "new-struct-path-tbaa">,
   HelpText<"Enable enhanced struct-path aware Type Based Alias Analysis">;
 def mdebug_pass : Separate<["-"], "mdebug-pass">,
   HelpText<"Enable additional debug output">,
   MarshallingInfoString<CodeGenOpts<"DebugPass">>;
-def mframe_pointer_EQ : Joined<["-"], "mframe-pointer=">,
-  HelpText<"Specify which frame pointers to retain.">, Values<"all,non-leaf,none">,
-  NormalizedValuesScope<"CodeGenOptions::FramePointerKind">, NormalizedValues<["All", "NonLeaf", "None"]>,
-  MarshallingInfoEnum<CodeGenOpts<"FramePointer">, "None">;
 def mabi_EQ_ieeelongdouble : Flag<["-"], "mabi=ieeelongdouble">,
   HelpText<"Use IEEE 754 quadruple-precision for long double">,
   MarshallingInfoFlag<LangOpts<"PPCIEEELongDouble">>;
 def mabi_EQ_vec_extabi : Flag<["-"], "mabi=vec-extabi">,
   HelpText<"Enable the extended Altivec ABI on AIX. Use volatile and nonvolatile vector registers">,
   MarshallingInfoFlag<LangOpts<"EnableAIXExtendedAltivecABI">>;
 def mfloat_abi : Separate<["-"], "mfloat-abi">,
   HelpText<"The float ABI to use">,

 
 def pic_level : Separate<["-"], "pic-level">,
   HelpText<"Value for __PIC__">,
   MarshallingInfoInt<LangOpts<"PICLevel">>;
 def pic_is_pie : Flag<["-"], "pic-is-pie">,
   HelpText<"File is for a position independent executable">,
   MarshallingInfoFlag<LangOpts<"PIE">>;
 
+def mframe_pointer_EQ : Joined<["-"], "mframe-pointer=">,
+  HelpText<"Specify which frame pointers to retain.">, Values<"all,non-leaf,none">,
+  NormalizedValuesScope<"CodeGenOptions::FramePointerKind">, NormalizedValues<["All", "NonLeaf", "None"]>,
+  MarshallingInfoEnum<CodeGenOpts<"FramePointer">, "None">;
+
 } // let Visibility = [CC1Option, FC1Option]
 
 let Visibility = [CC1Option] in {
 
 def fblocks_runtime_optional : Flag<["-"], "fblocks-runtime-optional">,
   HelpText<"Weakly link in the blocks runtime">,
   MarshallingInfoFlag<LangOpts<"BlocksRuntimeOptional">>;
 def fexternc_nounwind : Flag<["-"], "fexternc-nounwind">,

flang/test/Driver/driver-help-hidden.f90

 ! CHECK-NEXT: -fno-integrated-as      Disable the integrated assembler
 ! CHECK-NEXT: -fno-lto                Disable LTO mode (default)
 ! CHECK-NEXT: -fno-ppc-native-vector-element-order
 ! CHECK-NEXT:                         Specifies PowerPC non-native vector element order
 ! CHECK-NEXT: -fno-signed-zeros       Allow optimizations that ignore the sign of floating point zeros
 ! CHECK-NEXT: -fno-stack-arrays       Allocate array temporaries on the heap (default)
 ! CHECK-NEXT: -fno-version-loops-for-stride
 ! CHECK-NEXT:                         Do not create unit-strided loops (default)
+! CHECK-NEXT: -fomit-frame-pointer    Omit the frame pointer from functions that don't need it. Some stack unwinding cases, such as profilers and sanitizers, may prefer specifying -fno-omit-frame-pointer. On many targets, -O1 and higher omit the frame pointer by default. -m[no-]omit-leaf-frame-pointer takes precedence for leaf functions
 ! CHECK-NEXT: -fopenacc               Enable OpenACC
 ! CHECK-NEXT: -fopenmp-assume-no-nested-parallelism
 ! CHECK-NEXT:                         Assert no nested parallel regions in the GPU
 ! CHECK-NEXT: -fopenmp-assume-no-thread-state
 ! CHECK-NEXT:                         Assert no thread in a parallel region modifies an ICV
 ! CHECK-NEXT: -fopenmp-target-debug   Enable debugging in the OpenMP offloading device RTL
 ! CHECK-NEXT: -fopenmp-targets=<value>
 ! CHECK-NEXT:                         Specify comma-separated list of triples OpenMP offloading targets to be supported

flang/test/Driver/driver-help.f90

 ! HELP-NEXT: -fno-integrated-as      Disable the integrated assembler
 ! HELP-NEXT: -fno-lto                Disable LTO mode (default)
 ! HELP-NEXT: -fno-ppc-native-vector-element-order
 ! HELP-NEXT:                         Specifies PowerPC non-native vector element order
 ! HELP-NEXT: -fno-signed-zeros       Allow optimizations that ignore the sign of floating point zeros
 ! HELP-NEXT: -fno-stack-arrays       Allocate array temporaries on the heap (default)
 ! HELP-NEXT: -fno-version-loops-for-stride
 ! HELP-NEXT:                         Do not create unit-strided loops (default)
+! HELP-NEXT: -fomit-frame-pointer    Omit the frame pointer from functions that don't need it. Some stack unwinding cases, such as profilers and sanitizers, may prefer specifying -fno-omit-frame-pointer. On many targets, -O1 and higher omit the frame pointer by default. -m[no-]omit-leaf-frame-pointer takes precedence for leaf functions
 ! HELP-NEXT: -fopenacc               Enable OpenACC
 ! HELP-NEXT: -fopenmp-target-debug   Enable debugging in the OpenMP offloading device RTL
 ! HELP-NEXT: -fopenmp-targets=<value>
 ! HELP-NEXT:                         Specify comma-separated list of triples OpenMP offloading targets to be supported
 ! HELP-NEXT: -fopenmp-version=<value>
 ! HELP-NEXT:                         Set OpenMP version (e.g. 45 for OpenMP 4.5, 50 for OpenMP 5.0). Default value is 50 for Clang and 11 for Flang
 ! HELP-NEXT: -fopenmp                Parse OpenMP pragmas and generate parallel code.
 ! HELP-NEXT: -foptimization-record-file=<file>

 ! HELP-FC1-NEXT:                         Create unit-strided versions of loops
 ! HELP-FC1-NEXT: -fxor-operator          Enable .XOR. as a synonym of .NEQV.
 ! HELP-FC1-NEXT: -help                   Display available options
 ! HELP-FC1-NEXT: -init-only              Only execute frontend initialization
 ! HELP-FC1-NEXT: -I <dir>                Add directory to the end of the list of include search paths
 ! HELP-FC1-NEXT: -load <dsopath>         Load the named plugin (dynamic shared object)
 ! HELP-FC1-NEXT: -menable-no-infs        Allow optimization to assume there are no infinities.
 ! HELP-FC1-NEXT: -menable-no-nans        Allow optimization to assume there are no NaNs.
+! HELP-FC1-NEXT: -mframe-pointer=<value> Specify which frame pointers to retain.
 ! HELP-FC1-NEXT: -mllvm <value>          Additional arguments to forward to LLVM's option processing
 ! HELP-FC1-NEXT: -mmlir <value>          Additional arguments to forward to MLIR's option processing
 ! HELP-FC1-NEXT: -module-dir <dir>       Put MODULE files in <dir>
 ! HELP-FC1-NEXT: -module-suffix <suffix> Use <suffix> as the suffix for module files (the default value is `.mod`)
 ! HELP-FC1-NEXT: -mreassociate           Allow reassociation transformations for floating-point instructions
 ! HELP-FC1-NEXT: -mrelocation-model <value>
 ! HELP-FC1-NEXT:                         The relocation model to use
 ! HELP-FC1-NEXT: -nocpp                  Disable predefined and command line preprocessor macros

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

+! Test no error emitted with 'fomit-frame-pointer' flag.
+
+! Test opt_record flags get generated for fc1
+! RUN: %flang -fomit-frame-pointer %s
+
+program forttest
+    implicit none
+    integer :: n
+
+    n = 1
+
+end program forttest