Adds a Mach-O loader, similar to the existing ELF loader, that
can be used on platforms that do not support loading Mach-O dynamic
libraries via dlopen().
Other changes:
* Renames the --force-load-elf-from-memory command line argument
to --force-load-from-memory.
* Use CPU_TYPE_ANY and CPU_SUBTYPE_ANY for architectures that do
not have specific constants in <mach/machine.h> (e.g., RISCV),
as the snapshot header check after loading also catches architecture
mismatches.
* Emit the unwinding information at the end of the text segment
for Windows Mach-O snapshots as is done for ELF ones.
TEST=vm/dart/unobfuscated_static_symbols_test
vm/dart/use_dwarf_stack_traces_flag_test
Issue: https://github.com/dart-lang/sdk/issues/60307
Change-Id: I34a2a334f47d18d5c4f4a712956e71fd0ac94024
Cq-Include-Trybots: luci.dart.try:vm-aot-linux-debug-x64-try,vm-mac-release-arm64-try,vm-aot-mac-release-arm64-try,vm-aot-mac-release-x64-try,vm-aot-dwarf-linux-product-x64-try,vm-linux-debug-x64-try,vm-mac-debug-arm64-try,vm-fuchsia-release-x64-try,vm-fuchsia-release-arm64-try,vm-linux-debug-ia32-try,vm-aot-linux-debug-simarm_x64-try,vm-aot-linux-debug-simriscv32-try,vm-aot-linux-debug-simriscv64-try,vm-aot-linux-release-simarm_x64-try,vm-gcc-linux-try,vm-ubsan-linux-release-arm64-try,vm-aot-win-release-arm64-try,vm-aot-win-release-x64-try,vm-win-release-x64-try,vm-win-release-arm64-try,vm-aot-win-debug-arm64-try,vm-win-debug-arm64-try
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/430100
Reviewed-by: Slava Egorov <vegorov@google.com>
Reviewed-by: Ryan Macnak <rmacnak@google.com>
Tess Strickland