Unverified Commit 6e3ab87e authored by Ian Anderson's avatar Ian Anderson Committed by GitHub
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[cmake][compiler-rt][darwin] builtin libraries don't build for armv6m in Darwin (#195372) 

darwin_add_builtin_libraries tests for _Float16 and __bf16 for the host
architecture rather than the one being built, add -arch to fix that so
that armv6m correctly reports that it does not support __bf16.
cfcmp/cdcmp get "error: unsupported relocation type" on their "Branch to
target address" to c{f,d}cmple. Switch those to "Call a subroutine"
instructions on Thumb-1 (e.g. armv6m).

Assisted-by: Claude Code

rdar://167828904
parent 5847857b

compiler-rt/cmake/Modules/CompilerRTDarwinUtils.cmake

+3 −0
Original line number Diff line number Diff line
@@ -450,11 +450,14 @@ macro(darwin_add_builtin_libraries) 
                              OS ${os}

                              ARCH ${arch}

                              MIN_VERSION ${DARWIN_${os}_BUILTIN_MIN_VER})

      cmake_push_check_state()

      set(CMAKE_REQUIRED_FLAGS "${CMAKE_REQUIRED_FLAGS} -arch ${arch}")

      check_c_source_compiles("_Float16 foo(_Float16 x) { return x; }"

                              COMPILER_RT_HAS_${arch}_FLOAT16)

      append_list_if(COMPILER_RT_HAS_${arch}_FLOAT16 -DCOMPILER_RT_HAS_FLOAT16 BUILTIN_CFLAGS_${arch})

      check_c_source_compiles("__bf16 foo(__bf16 x) { return x; }"

                              COMPILER_RT_HAS_${arch}_BFLOAT16)

      cmake_pop_check_state()

      # Build BF16 files only when "__bf16" is available.

      if(COMPILER_RT_HAS_${arch}_BFLOAT16)

        list(APPEND ${arch}_SOURCES ${BF16_SOURCES})

compiler-rt/lib/builtins/arm/aeabi_cdcmp.S

+6 −0
Original line number Diff line number Diff line
@@ -156,7 +156,13 @@ DEFINE_COMPILERRT_FUNCTION(__aeabi_cdrcmple) 
        mov r1, r3

        mov r3, ip



#if defined(USE_THUMB_1)

        push {r0, lr}

        bl __aeabi_cdcmple

        pop {r0, pc}

#else

        b __aeabi_cdcmple

#endif

END_COMPILERRT_FUNCTION(__aeabi_cdrcmple)



NO_EXEC_STACK_DIRECTIVE

compiler-rt/lib/builtins/arm/aeabi_cfcmp.S

+6 −0
Original line number Diff line number Diff line
@@ -151,7 +151,13 @@ DEFINE_COMPILERRT_FUNCTION(__aeabi_cfrcmple) 
        mov r0, r1

        mov r1, ip



#if defined(USE_THUMB_1)

        push {r0, lr}

        bl __aeabi_cfcmple

        pop {r0, pc}

#else

        b __aeabi_cfcmple

#endif

END_COMPILERRT_FUNCTION(__aeabi_cfrcmple)



NO_EXEC_STACK_DIRECTIVE