CustomMain NativeAot test doesn't support cross-arch compilation

[sbomer]

The testcase added in #81873 doesn't currently work when cross-building tests from x64 for arm64.

When I do a cross-build of the tests, this is the command-line that gets used to compile the native object:
cd /home/svbomer/src/runtime/artifacts/tests/coreclr/obj/linux.arm64.Release/Native/nativeaot/CustomMain && /usr/bin/clang++-15 -DDISABLE_CONTRACTS -DHOST_64BIT -DHOST_AMD64 -DHOST_UNIX -DNDEBUG -DTARGET_64BIT -DTARGET_AMD64 -DTARGET_LINUX -DTARGET_UNIX -DURTBLDENV_FRIENDLY=Retail -D_FILE_OFFSET_BITS=64 -I/home/svbomer/src/runtime/src/native -I/home/svbomer/src/runtime/src/tests/Common/Platform -O3 -DNDEBUG -fPIC -O3 -g -Wall -Wno-null-conversion -fno-omit-frame-pointer -fms-extensions -fwrapv -fstack-protector-strong -Werror -Wno-unused-variable -Wno-unused-value -Wno-unused-function -Wno-tautological-compare -Wno-unknown-pragmas -Wimplicit-fallthrough -Wno-invalid-offsetof -Wno-unused-but-set-variable -ffp-contract=off -fno-rtti -Wno-unknown-warning-option -ferror-limit=4096 -Wno-unused-private-field -Wno-constant-logical-operand -Wno-pragma-pack -Wno-incompatible-ms-struct -Wno-reserved-identifier -Wno-unsafe-buffer-usage -Wno-single-bit-bitfield-constant-conversion -Wno-cast-function-type-strict -fsigned-char -fvisibility=hidden -ffunction-sections -std=gnu++11 -MD -MT nativeaot/CustomMain/CMakeFiles/CustomMainNative.dir/CustomMainNative.cpp.o -MF CMakeFiles/CustomMainNative.dir/CustomMainNative.cpp.o.d -o CMakeFiles/CustomMainNative.dir/CustomMainNative.cpp.o -c /home/svbomer/src/runtime/src/tests/nativeaot/CustomMain/CustomMainNative.cpp

Notice the -DTARGET_AMD64. The test gets compiled for amd64 even though I am asking to build for arm64:

ROOTFS_DIR=`pwd`/../crossrootfs/arm64 ./src/tests/build.sh -arm64 nativeaot Release test nativeaot/CustomMain/CustomMain.csproj

which results in downstream errors later in the build:

/usr/bin/aarch64-linux-gnu-ld: /home/svbomer/src/runtime/artifacts/tests/coreclr/linux.arm64.Release/nativeaot/CustomMain/CustomMain/libCustomMainNative.a(CustomMainNative.cpp.o): Relocations in generic ELF (EM: 62)

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Issue Details

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The testcase added in #81873 doesn't currently work when cross-building tests from x64 for arm64.

When I do a cross-build of the tests, this is the command-line that gets used to compile the native object:
cd /home/svbomer/src/runtime/artifacts/tests/coreclr/obj/linux.arm64.Release/Native/nativeaot/CustomMain && /usr/bin/clang++-15 -DDISABLE_CONTRACTS -DHOST_64BIT -DHOST_AMD64 -DHOST_UNIX -DNDEBUG -DTARGET_64BIT -DTARGET_AMD64 -DTARGET_LINUX -DTARGET_UNIX -DURTBLDENV_FRIENDLY=Retail -D_FILE_OFFSET_BITS=64 -I/home/svbomer/src/runtime/src/native -I/home/svbomer/src/runtime/src/tests/Common/Platform -O3 -DNDEBUG -fPIC -O3 -g -Wall -Wno-null-conversion -fno-omit-frame-pointer -fms-extensions -fwrapv -fstack-protector-strong -Werror -Wno-unused-variable -Wno-unused-value -Wno-unused-function -Wno-tautological-compare -Wno-unknown-pragmas -Wimplicit-fallthrough -Wno-invalid-offsetof -Wno-unused-but-set-variable -ffp-contract=off -fno-rtti -Wno-unknown-warning-option -ferror-limit=4096 -Wno-unused-private-field -Wno-constant-logical-operand -Wno-pragma-pack -Wno-incompatible-ms-struct -Wno-reserved-identifier -Wno-unsafe-buffer-usage -Wno-single-bit-bitfield-constant-conversion -Wno-cast-function-type-strict -fsigned-char -fvisibility=hidden -ffunction-sections -std=gnu++11 -MD -MT nativeaot/CustomMain/CMakeFiles/CustomMainNative.dir/CustomMainNative.cpp.o -MF CMakeFiles/CustomMainNative.dir/CustomMainNative.cpp.o.d -o CMakeFiles/CustomMainNative.dir/CustomMainNative.cpp.o -c /home/svbomer/src/runtime/src/tests/nativeaot/CustomMain/CustomMainNative.cpp

Notice the -DTARGET_AMD64. The test gets compiled for amd64 even though I am asking to build for arm64:

ROOTFS_DIR=`pwd`/../crossrootfs/arm64 ./src/tests/build.sh -arm64 nativeaot Release test nativeaot/CustomMain/CustomMain.csproj

which results in downstream errors later in the build:

/usr/bin/aarch64-linux-gnu-ld: /home/svbomer/src/runtime/artifacts/tests/coreclr/linux.arm64.Release/nativeaot/CustomMain/CustomMain/libCustomMainNative.a(CustomMainNative.cpp.o): Relocations in generic ELF (EM: 62)

Author:	sbomer
Assignees:	-
Labels:	area-NativeAOT-coreclr
Milestone:	-

[sbomer]

Same issue for the SharedLibrary nativeaot test:
cd /home/svbomer/src/runtime/artifacts/tests/coreclr/obj/linux.arm64.Release/Native/nativeaot/SmokeTests/SharedLibrary && /usr/bin/clang++-15 -DDISABLE_CONTRACTS -DHOST_64BIT -DHOST_AMD64 -DHOST_UNIX -DNDEBUG -DTARGET_64BIT -DTARGET_AMD64 -DTARGET_LINUX -DTARGET_UNIX -DURTBLDENV_FRIENDLY=Retail -D_FILE_OFFSET_BITS=64 -I/home/svbomer/src/runtime/src/native -I/home/svbomer/src/runtime/src/tests/Common/Platform -O3 -DNDEBUG -fPIE -fPIE -O3 -g -Wall -Wno-null-conversion -fno-omit-frame-pointer -fms-extensions -fwrapv -fstack-protector-strong -Werror -Wno-unused-variable -Wno-unused-value -Wno-unused-function -Wno-tautological-compare -Wno-unknown-pragmas -Wimplicit-fallthrough -Wno-invalid-offsetof -Wno-unused-but-set-variable -ffp-contract=off -fno-rtti -Wno-unknown-warning-option -ferror-limit=4096 -Wno-unused-private-field -Wno-constant-logical-operand -Wno-pragma-pack -Wno-incompatible-ms-struct -Wno-reserved-identifier -Wno-unsafe-buffer-usage -Wno-single-bit-bitfield-constant-conversion -Wno-cast-function-type-strict -fsigned-char -fvisibility=hidden -ffunction-sections -std=gnu++11 -MD -MT nativeaot/SmokeTests/SharedLibrary/CMakeFiles/SharedLibraryDriver.dir/SharedLibrary.cpp.o -MF CMakeFiles/SharedLibraryDriver.dir/SharedLibrary.cpp.o.d -o CMakeFiles/SharedLibraryDriver.dir/SharedLibrary.cpp.o -c /home/svbomer/src/runtime/src/tests/nativeaot/SmokeTests/SharedLibrary/SharedLibrary.cpp

This one fails not when building tests (since this just builds the shared library, and doesn't need to statically link it), but when running the:

/root/helix/work/correlation/nativeaottest.sh: line 15: /root/helix/work/workitem/e/nativeaot/SmokeTests/SharedLibrary/SharedLibrary//native/SharedLibrary: cannot execute binary file: Exec format error

And similar for the Pinvoke test, which compiles a native shared library. This one fails to load the shared lib dependency at runtime:

Unhandled Exception: System.DllNotFoundException: Unable to load shared library 'PInvokeNative' or one of its dependencies. In order to help diagnose loading problems, consider using a tool 

[am11]

ROOTFS_DIR=pwd/../crossrootfs/arm64 ./src/tests/build.sh -arm64 nativeaot Release test nativeaot/CustomMain/CustomMain.csproj

Missing -cross argument? Try

ROOTFS_DIR=/crossrootfs/arm64 ./src/tests/build.sh -cross -arm64 nativeaot Release test nativeaot/CustomMain/CustomMain.csproj

(-cross maps to /p:CrossBuild=true)

[am11]

Notice the -DTARGET_AMD64.

btw, this define by itself is not the indicator of cross compilation. In the context of clang (as linker driver) command line, the argument for cross target to look for is -target.

[sbomer]

Seems this was a user error - this now seems to work if I pass the right -cross argument.