[Builtin] [ARM] Update CMake to support the build of armv6m

[weimingz]

Summary

Setting -DCOMPILER_RT_TEST_TARGET_TRIPLE=armv6m-none-eabi will enable the build of builtin functions ARMv6m.
Currently, only those asms that support armv6m are added.

TODO:All asm sin ARM_EABI_Sources are ported for thumb1 so Thumb1_EABI_Sources will be deprecated.

[rengolin]

cmake/base-config-ix.cmake

169

Why not just add a test_target_arch inside the MATCHES "arm" below?

[compnerd]

cmake/base-config-ix.cmake

177

How are you planning on dealing with arm and armv6m builds stomping each other? IIRC, the output file name is the same for both builds.

[weimingz]

cmake/base-config-ix.cmake

177

They have different build directories:
ls lib/builtins/CMakeFiles \

clang_rt.builtins-arm.dir  clang_rt.builtins-armv6m.dir

and separate output files:
ls lib/linux/libclang_rt.builtins-arm*.a

lib/linux/libclang_rt.builtins-arm.a  lib/linux/libclang_rt.builtins-armv6m.a

[weimingz]

cmake/base-config-ix.cmake

177

Hi Saleem, does it answer your question?

[compnerd]

Ah, sorry, missed that response. Yes, that answers the question, I didnt realize that the file got named differently. SG

[kubamracek]

Hi, this causes build failures one of our internal Darwin machines when building the lib/builtins/arm/comparesf2.S file with -ffreestanding -arch armv6m -static -mfloat-abi=soft:

./lib/builtins/arm/comparesf2.S:72:5: error: instruction requires: arm-mode
    orrs r6, r2, r6
./lib/builtins/arm/comparesf2.S:197:5: error: instruction requires: arm-mode
    orrs r6, r2, r6

Any ideas why?

[rengolin]

Hum, I believe the three-reg encoding is for Thumb2/ARM only, but apparently present in v6M. Since those sources are named "thumb1_sources" we can't have v6M-specific encodings in there. I missed that one, apparently.

@weimingz, can you have a look and use a Thumb1-specific encoding instead? Also, for all the other instructions, please check the ARM ARM to make sure they're allowed pre-v6 and are strictly 16-bit encodings.

[weimingz]

I included the fix in https://reviews.llvm.org/D28971

cmake/base-config-ix.cmake

elseif("${COMPILER_RT_DEFAULT_TARGET_ARCH}" MATCHES "mipsel|mips64el")
       # clang's default CPU's. In the 64-bit case, we must also specify the ABI
       # since the default ABI differs between gcc and clang.
       # FIXME: Ideally, we would build the N32 library too.
       test_target_arch(mipsel "" "-mips32r2" "--target=mipsel-linux-gnu")
       test_target_arch(mips64el "" "-mips64r2" "--target=mips64el-linux-gnu" "-mabi=64")
     elseif("${COMPILER_RT_DEFAULT_TARGET_ARCH}" MATCHES "mips")
       test_target_arch(mips "" "-mips32r2" "--target=mips-linux-gnu")
       test_target_arch(mips64 "" "-mips64r2" "--target=mips64-linux-gnu" "-mabi=64")
+    elseif("${COMPILER_RT_DEFAULT_TARGET_ARCH}" MATCHES "armv6m")
+      test_target_arch(armv6m "" "-march=armv6m" "-mfloat-abi=soft")
     elseif("${COMPILER_RT_DEFAULT_TARGET_ARCH}" MATCHES "arm")
       if(WIN32)
         test_target_arch(arm "" "" "")
       else()
         test_target_arch(arm "" "-march=armv7-a" "-mfloat-abi=soft")
         test_target_arch(armhf "" "-march=armv7-a" "-mfloat-abi=hard")
       endif()
     elseif("${COMPILER_RT_DEFAULT_TARGET_ARCH}" MATCHES "aarch32")
       test_target_arch(aarch32 "" "-march=armv8-a")
     elseif("${COMPILER_RT_DEFAULT_TARGET_ARCH}" MATCHES "aarch64")
       test_target_arch(aarch64 "" "-march=armv8-a")
     elseif("${COMPILER_RT_DEFAULT_TARGET_ARCH}" MATCHES "wasm32")
       test_target_arch(wasm32 "" "--target=wasm32-unknown-unknown")
     elseif("${COMPILER_RT_DEFAULT_TARGET_ARCH}" MATCHES "wasm64")
       test_target_arch(wasm64 "" "--target=wasm64-unknown-unknown")
     endif()
     set(COMPILER_RT_OS_SUFFIX "")
   endif()
 endmacro()

cmake/builtin-config-ix.cmake

 int foo(int x, int y) {
  _Atomic int result = x * y;
  return result;
 }
 ")
 
 
 set(ARM64 aarch64)
-set(ARM32 arm armhf)
+set(ARM32 arm armhf armv6m)
 set(X86 i386 i686)
 set(X86_64 x86_64)
 set(MIPS32 mips mipsel)
 set(MIPS64 mips64 mips64el)
 set(PPC64 powerpc64 powerpc64le)
 set(WASM32 wasm32)
 set(WASM64 wasm64)
 

lib/builtins/CMakeLists.txt

set(arm_SOURCES
   arm/sync_fetch_and_umin_8.S
   arm/sync_fetch_and_xor_4.S
   arm/sync_fetch_and_xor_8.S
   arm/udivmodsi4.S
   arm/udivsi3.S
   arm/umodsi3.S
   ${GENERIC_SOURCES})
 
+set(thumb1_SOURCES
+  arm/divsi3.S
+  arm/udivsi3.S
+  arm/comparesf2.S
+  ${GENERIC_SOURCES})
+
 set(arm_EABI_SOURCES
   arm/aeabi_cdcmp.S
   arm/aeabi_cdcmpeq_check_nan.c
   arm/aeabi_cfcmp.S
   arm/aeabi_cfcmpeq_check_nan.c
   arm/aeabi_dcmp.S
   arm/aeabi_div0.c
   arm/aeabi_drsub.c
   arm/aeabi_fcmp.S
   arm/aeabi_frsub.c
   arm/aeabi_idivmod.S
   arm/aeabi_ldivmod.S
   arm/aeabi_memcmp.S
   arm/aeabi_memcpy.S
   arm/aeabi_memmove.S
   arm/aeabi_memset.S
   arm/aeabi_uidivmod.S
   arm/aeabi_uldivmod.S)
+
+set(thumb1_EABI_SOURCES
+  arm/aeabi_cdcmpeq_check_nan.c
+  arm/aeabi_cfcmpeq_check_nan.c
+  arm/aeabi_div0.c
+  arm/aeabi_drsub.c
+  arm/aeabi_fcmp.S
+  arm/aeabi_frsub.c
+  arm/aeabi_idivmod.S
+  arm/aeabi_memcmp.S
+  arm/aeabi_memcpy.S
+  arm/aeabi_memmove.S
+  arm/aeabi_uidivmod.S)
+
 set(arm_Thumb1_JT_SOURCES
   arm/switch16.S
   arm/switch32.S
   arm/switch8.S
   arm/switchu8.S)
 set(arm_Thumb1_SjLj_EH_SOURCES
   arm/restore_vfp_d8_d15_regs.S
   arm/save_vfp_d8_d15_regs.S)
set(arm_SOURCES
       udivsi3.c
       umoddi3.c)
 elseif(NOT WIN32)
   # TODO the EABI sources should only be added to EABI targets
   set(arm_SOURCES
     ${arm_SOURCES}
     ${arm_EABI_SOURCES}
     ${arm_Thumb1_SOURCES})
+
+  set(thumb1_SOURCES
+    ${thumb1_SOURCES}
+    ${thumb1_EABI_SOURCES})
 endif()
 
 set(aarch64_SOURCES
   comparetf2.c
   extenddftf2.c
   extendsftf2.c
   fixtfdi.c
   fixtfsi.c

 
 set(armhf_SOURCES ${arm_SOURCES})
 set(armv7_SOURCES ${arm_SOURCES})
 set(armv7s_SOURCES ${arm_SOURCES})
 set(armv7k_SOURCES ${arm_SOURCES})
 set(arm64_SOURCES ${aarch64_SOURCES})
 
 # macho_embedded archs
-set(armv6m_SOURCES ${GENERIC_SOURCES})
+set(armv6m_SOURCES ${thumb1_SOURCES})
 set(armv7m_SOURCES ${arm_SOURCES})
 set(armv7em_SOURCES ${arm_SOURCES})
 
 set(mips_SOURCES ${GENERIC_SOURCES})
 set(mipsel_SOURCES ${mips_SOURCES})
 set(mips64_SOURCES ${mips_SOURCES})
 set(mips64el_SOURCES ${mips_SOURCES})