This relands commit 13dd65b3a1.
The original commit contained a test, which failed when compiled
for a MACH-O target.
This patch changes the test to run for x86_64-linux instead of
`%itanium_abi_triple`, to avoid having invalid syntax for MACH-O
sections. The patch itself does not care about section attribute
syntax and a x86 backend does not even need to be included in the
build.
Differential Revision: https://reviews.llvm.org/D102693
When a const-qualified object has a section attribute, that
section is set to read-only and clang outputs a LLVM IR constant
for that object. This is incorrect for dynamically initialised
objects.
For example:
int init() { return 15; }
__attribute__((section("SA")))
const int a = init();
a is allocated to a read-only section and is left
unintialised (zero-initialised).
This patch adds checks if an initialiser is a constant expression
and allocates objects to sections as follows:
* const-qualified objects
- no initialiser or constant initialiser: .rodata
- dynamic initializer: .bss
* non const-qualified objects
- no initialiser or dynamic initialiser: .bss
- constant initialiser: .data
(".rodata", ".data", and ".bss" names used just for explanatory
purpose)
Differential Revision: https://reviews.llvm.org/D102693
Momchil Velikov