For a default visibility external linkage definition, dso_local is set for ELF
-fno-pic/-fpie and COFF and Mach-O. Since default clang -cc1 for ELF is similar
to -fpic ("PIC Level" is not set), this nuance causes unneeded binary format differences.
To make emitted IR similar, ELF -cc1 -fpic will default to -fno-semantic-interposition,
which sets dso_local for default visibility external linkage definitions.
To make this flip smooth and enable future (dso_local as definition default),
this patch replaces (function) `define ` with `define{{.*}} `,
(variable/constant/alias) `= ` with `={{.*}} `, or inserts appropriate `{{.*}} `.
The expected strings would previously not catch bugs when redzones were
added when they were not actually expected. Fix by adding "global "
before the type.
Some platforms do not support aliases. Split the test, and pass explicit
triple to avoid test failure.
Reviewed By: thakis
Tags: #clang
Differential Revision: https://reviews.llvm.org/D81591
Fangrui Song