clangd/.github/workflows/lib_compat.h
Kadir Cetinkaya 40114796f0 Include lib_compat.h while building gRPC
While building clangd binaries we set required glibc version for symbols
to a minimum to cover systems with older glibc implementations. But we
were not doing that while building gRPC, which might depend on never
versions of these symbols.
2021-02-26 12:50:28 +01:00

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C

// This header forces the use of a particular version of glibc symbols.
// This can make the resulting binary portable to systems with older glibcs.
//
// It must be included in each TU, with CFLAGS="-include glibc_compat.h" etc.
//
// We only list symbols known to be used. This is paired with a test enforcing
// the max glibc symbol version. If the test fails, the list should be extended.
// Find the old alternatives version to target with e.g.:
// objdump -T /lib/x86_64-linux-gnu/lib{c,m,pthread,rt}.so.* | grep "\bexpf\b"
#define FORCE_SYMBOL_VERSION(sym, version) \
__asm__(".symver " #sym "," #sym "@" #version)
FORCE_SYMBOL_VERSION(exp2, GLIBC_2.2.5);
FORCE_SYMBOL_VERSION(expf, GLIBC_2.2.5);
FORCE_SYMBOL_VERSION(log, GLIBC_2.2.5);
FORCE_SYMBOL_VERSION(log2, GLIBC_2.2.5);
FORCE_SYMBOL_VERSION(pow, GLIBC_2.2.5);
#undef FORCE_SYMBOL_VERSION