[Driver] Allow Classic Flang driver to accept more Clang options

This patch cherry-picks a number of Visibility changes from the tip of trunk
upstream, to make selected Clang options visible to Classic Flang. It also
makes target-specific codegen options (-mxxxx) visible to Flang by default.
Note that accepting the option does not imply support; Classic Flang may
simply ignore certain options for backward compatibility.

Author: bryanpkc

clang/include/clang/Driver/Options.td

@@ -195,7 +195,11 @@ def hip_Group : OptionGroup<"<HIP group>">, Group<f_Group>,
 
 def m_Group : OptionGroup<"<m group>">, Group<CompileOnly_Group>,
               DocName<"Target-dependent compilation options">,
+#ifdef ENABLE_CLASSIC_FLANG
+              Visibility<[ClangOption, CLOption, FlangOption]>;
+#else
               Visibility<[ClangOption, CLOption]>;
+#endif
 
 def hlsl_Group : OptionGroup<"<HLSL group>">, Group<f_Group>,
                    DocName<"HLSL options">,
@@ -231,10 +235,18 @@ def m_wasm_Features_Group : OptionGroup<"<wasm features group>">,
 def m_wasm_Features_Driver_Group : OptionGroup<"<wasm driver features group>">,
                                    Group<m_Group>, DocName<"WebAssembly Driver">;
 def m_x86_Features_Group : OptionGroup<"<x86 features group>">,
+#ifdef ENABLE_CLASSIC_FLANG
+                           Group<m_Group>, Visibility<[ClangOption, CLOption, FlangOption]>,
+#else
                            Group<m_Group>, Visibility<[ClangOption, CLOption]>,
+#endif
                            DocName<"X86">;
 def m_x86_AVX10_Features_Group : OptionGroup<"<x86 AVX10 features group>">,
+#ifdef ENABLE_CLASSIC_FLANG
+                                 Group<m_Group>, Visibility<[ClangOption, CLOption, FlangOption]>,
+#else
                                  Group<m_Group>, Visibility<[ClangOption, CLOption]>,
+#endif
                                  DocName<"X86 AVX10">;
 def m_riscv_Features_Group : OptionGroup<"<riscv features group>">,
                              Group<m_Group>, DocName<"RISC-V">;
@@ -3516,7 +3528,11 @@ def fno_realloc_lhs : Flag<["-"], "fno-realloc-lhs">, Group<f_Group>,
 def fno_stack_protector : Flag<["-"], "fno-stack-protector">, Group<f_Group>,
   HelpText<"Disable the use of stack protectors">;
 def fno_strict_aliasing : Flag<["-"], "fno-strict-aliasing">, Group<f_Group>,
+#ifdef ENABLE_CLASSIC_FLANG
+  Visibility<[ClangOption, CLOption, DXCOption, FlangOption]>,
+#else
   Visibility<[ClangOption, CLOption, DXCOption]>,
+#endif
   HelpText<"Disable optimizations based on strict aliasing rules">;
 def fstruct_path_tbaa : Flag<["-"], "fstruct-path-tbaa">, Group<f_Group>;
 def fno_struct_path_tbaa : Flag<["-"], "fno-struct-path-tbaa">, Group<f_Group>;

clang/test/Driver/flang/classic-flang.f95

@@ -2,15 +2,17 @@
 
 ! Check that the driver invokes flang1 correctly for preprocessed free-form
 ! Fortran code. Also check that the backend is invoked correctly.
+! In particular, target-dependent flags (e.g. -mavx for x86_64) should be visible.
 
-! RUN: %clang --driver-mode=flang -target x86_64-unknown-linux-gnu -c %s -### 2>&1 \
+! RUN: %clang --driver-mode=flang -target x86_64-unknown-linux-gnu -mavx -c %s -### 2>&1 \
 ! RUN:   | FileCheck --check-prefix=CHECK-OBJECT %s
 ! CHECK-OBJECT: "{{.*}}flang1"
 ! CHECK-OBJECT-NOT: "-preprocess"
 ! CHECK-OBJECT-SAME: "-freeform"
 ! CHECK-OBJECT-NEXT: "{{.*}}flang2"
 ! CHECK-OBJECT-SAME: "-asm" [[LLFILE:.*.ll]]
 ! CHECK-OBJECT-NEXT: {{clang.* "-cc1"}}
+! CHECK-OBJECT-SAME: "-target-feature" "+avx"
 ! CHECK-OBJECT-SAME: "-o" "classic-flang.o"
 ! CHECK-OBJECT-SAME: "-x" "ir"
 ! CHECK-OBJECT-SAME: [[LLFILE]]
@@ -31,17 +33,33 @@
 
 ! Check that the backend job (clang -cc1) is not combined into the compile job
 ! (flang2) even if -integrated-as is specified.
+! Also, check that AArch64-specific target-dependent flags are visible.
 
-! RUN: %clang --driver-mode=flang -target x86_64-unknown-linux-gnu -integrated-as -S %s -### 2>&1 \
+! RUN: %clang --driver-mode=flang -target aarch64-unknown-linux-gnu -integrated-as -mno-outline-atomics -S %s -### 2>&1 \
 ! RUN:   | FileCheck --check-prefix=CHECK-ASM %s
 ! CHECK-ASM: "{{.*}}flang1"
 ! CHECK-ASM-NEXT: "{{.*}}flang2"
 ! CHECK-ASM-SAME: "-asm" [[LLFILE:.*.ll]]
 ! CHECK-ASM-NEXT: {{clang.* "-cc1"}}
+! CHECK-ASM-SAME: "-target-feature" "-outline-atomics"
 ! CHECK-ASM-SAME: "-o" "classic-flang.s"
 ! CHECK-ASM-SAME: "-x" "ir"
 ! CHECK-ASM-SAME: [[LLFILE]]
 
+! Check that other target-independent compiler flags are visible.
+! RUN: %clang --driver-mode=flang -target x86_64-unknown-linux-gnu --gcc-install-dir=%S/../Inputs/debian_multiarch_tree/usr/lib/gcc/x86_64-linux-gnu/10/ -fno-strict-aliasing -funroll-loops %s -### 2>&1 \
+! RUN:   | FileCheck --check-prefix=CHECK-FFLAGS %s
+! CHECK-FFLAGS: "{{.*}}flang1"
+! CHECK-FFLAGS-NEXT: "{{.*}}flang2"
+! CHECK-FFLAGS-SAME: "-asm" [[LLFILE:.*.ll]]
+! CHECK-FFLAGS-NEXT: {{clang.* "-cc1"}}
+! CHECK-FFLAGS-SAME: "-relaxed-aliasing"
+! CHECK-FFLAGS-SAME: "-funroll-loops"
+! CHECK-FFLAGS-SAME: "-x" "ir"
+! CHECK-FFLAGS-SAME: [[LLFILE]]
+! CHECK-FFLAGS-NEXT: "{{.*}}ld{{(.exe)?}}"
+! CHECK-FFLAGS-SAME: "-L{{[^ ]*[/\\]+}}debian_multiarch_tree/usr/lib/gcc/x86_64-linux-gnu/10"
+
 ! Check that the linker job is given the correct libraries and library paths.
 
 ! RUN: %flang -target x86_64-linux-gnu -ccc-install-dir %S/../Inputs/basic_linux_tree/usr/bin -mp \