Bug #22401
open
addr2line.c does not build when crt_externs.h is absent (iOS SDK)
Description
Ruby version: master (4.0.7)
addr2line.c includes <crt_externs.h> unconditionally. The build fails on
Darwin targets where that header is absent. The public iOS SDK does not
ship crt_externs.h.
Steps to reproduce¶
Configure Ruby for a Darwin target without crt_externs.h, then run make.
One example is a cross-compile for armv7-apple-ios6.0 against the iOS 6.1
SDK:
SDK=/path/to/iPhoneOS6.1.sdk
CC="clang -target armv7-apple-ios6.0 -isysroot $SDK" \
CPP="clang -target armv7-apple-ios6.0 -isysroot $SDK -E" \
../ruby/configure --host=armv7-apple-darwin10 --build=aarch64-apple-darwin25
make
Actual result¶
Expected result¶
addr2line.c compiles.
Cause¶
Three other files already handle this case: hash.c, eval_intern.h and
missing/setproctitle.c. They check HAVE_CRT_EXTERNS_H. When the header is
absent, they include missing/crt_externs.h instead. configure.ac sets that
macro for darwin targets. addr2line.c was missed.
addr2line.c also calls _NSGetMachExecuteHeader(). Only the macOS
crt_externs.h declares that function, so a fallback header alone is not
sufficient. The fix must also declare the function locally, with the same
LP64 distinction that crt_externs.h uses. The symbol itself exists in
libSystem/dyld on iOS too.
Proposed fix¶
Branch: https://github.com/DominikAlberski/ruby/tree/fix/addr2line-crt-externs-fallback
macOS behavior does not change. On macOS HAVE_CRT_EXTERNS_H is defined, so
the includes and the declarations stay the same. I verified this by
preprocessing both versions with HAVE_CRT_EXTERNS_H defined. The output is
identical, apart from the LINE numbers that the added lines shift.
A test is not possible for this change. The code path is a compile-time
header fallback, and macOS builds do not take it.
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