I’m currently trying to build LLVM for android, it works fine until I get to i686-linux-android.
I really don’t understand why this is happening and what is happening there, I added some debug output to the llvm CMakeList.txt file:
# ...
foreach(t ${LLVM_TARGETS_TO_BUILD})
set( td ${LLVM_MAIN_SRC_DIR}/lib/Target/${t} )
message("t: \"${t}\"")
message("LLVM_ALL_TARGETS: \"${LLVM_ALL_TARGETS}\"")
list(GET LLVM_ALL_TARGETS 17 LLVM_ALL_TARGETS_17)
message("LLVM_ALL_TARGETS_17: \"${LLVM_ALL_TARGETS_17}\"")
string(HEX ${t} HEX_STRING1)
message("HEX_STRING1: ${HEX_STRING1}")
string(HEX ${LLVM_ALL_TARGETS_17} HEX_STRING2)
message("HEX_STRING2: ${HEX_STRING2}")
if (${t} IN_LIST LLVM_ALL_TARGETS)
message("A CONTAINED IN LLVM TARGET")
else()
message("A NOT CONTAINED IN LLVM TARGET")
endif()
if (${LLVM_ALL_TARGETS_17} IN_LIST LLVM_ALL_TARGETS)
message("B CONTAINED IN LLVM TARGET")
else()
message("B NOT CONTAINED IN LLVM TARGET")
endif()
# Make sure that any experimental targets were passed via
# LLVM_EXPERIMENTAL_TARGETS_TO_BUILD, not LLVM_TARGETS_TO_BUILD.
# We allow experimental targets that are not in LLVM_ALL_EXPERIMENTAL_TARGETS,
# as long as they are passed via LLVM_EXPERIMENTAL_TARGETS_TO_BUILD.
if ( NOT ${t} IN_LIST LLVM_ALL_TARGETS AND NOT ${t} IN_LIST LLVM_EXPERIMENTAL_TARGETS_TO_BUILD )
if( ${t} IN_LIST LLVM_ALL_EXPERIMENTAL_TARGETS )
message(FATAL_ERROR "The target `${t}' is experimental and must be passed "
"via LLVM_EXPERIMENTAL_TARGETS_TO_BUILD.")
else()
message(FATAL_ERROR "The target `${t}' is not a core tier target. It may be "
"experimental, if so it must be passed via "
"LLVM_EXPERIMENTAL_TARGETS_TO_BUILD.\n"
"Core tier targets: ${LLVM_ALL_TARGETS}\n"
"Known experimental targets: ${LLVM_ALL_EXPERIMENTAL_TARGETS}")
endif()
else()
set(LLVM_ENUM_TARGETS "${LLVM_ENUM_TARGETS}LLVM_TARGET(${t})\n")
endif()
# ....
This is the output this gives me:
...
t: "X86"
LLVM_ALL_TARGETS: "AArch64;AMDGPU;ARM;AVR;BPF;Hexagon;Lanai;LoongArch;Mips;MSP430;NVPTX;PowerPC;RISCV;Sparc;SystemZ;VE;WebAssembly;X86;XCore"
LLVM_ALL_TARGETS_17: "X86"
HEX_STRING1: 583836
HEX_STRING2: 583836
A NOT CONTAINED IN LLVM TARGET
B NOT CONTAINED IN LLVM TARGET
CMake Error at CMakeLists.txt:955 (message):
The target `X86' is not a core tier target. It may be experimental, if so
it must be passed via LLVM_EXPERIMENTAL_TARGETS_TO_BUILD.
Core tier targets:
AArch64;AMDGPU;ARM;AVR;BPF;Hexagon;Lanai;LoongArch;Mips;MSP430;NVPTX;PowerPC;RISCV;Sparc;SystemZ;VE;WebAssembly;X86;XCore
Known experimental targets: ARC;CSKY;DirectX;M68k;SPIRV;Xtensa
-- Configuring incomplete, errors occurred!
How is this even possible? LLVM_ALL_TARGETS contains X86 I can access it with list(GET …). I’m even checking for the hex value, to make sure it’s not a weird ASCII character.
It works fine for ARM, AArch64, even for X86_64, how is this possible? 
EDIT:
It appears to be related to using the android ndk (r25c), as soon as the CMAKE_TOOLCHAIN_FILE is set the error happens.
Also the following change in llvm\CMakeLists.txt would make it work:
# Changing this:
if ( NOT ${t} IN_LIST LLVM_ALL_TARGETS AND NOT ${t} IN_LIST LLVM_EXPERIMENTAL_TARGETS_TO_BUILD )
# To that
if ( NOT "${t}" IN_LIST LLVM_ALL_TARGETS AND NOT "${t}" IN_LIST LLVM_EXPERIMENTAL_TARGETS_TO_BUILD )
Any ideas why this could happend? Also it doesn’t feel right to change the llvm CMakeLists.txt file for that, feels like there is another underlying issue here?
