5 Commits

Author SHA1 Message Date
Fangrui Song
668da8c361 [MC] Set the unique id of .stack_sizes to the associated .text section's
Similar to D92113. Currently `clang -fstack-size-section -fno-unique-section-names`
sets the linked-to symbol to the first `.text`, which is:

* incorrect for COMDAT sections
* inferior for non-COMDAT sections in -ffunction-sections mode (poor --gc-sections: .stack_sizes cannot be separately discarded)

Note, if the section symbol can be referenced in more places (if the
function begin symbol does not apply), we probably should consider
defining a different BeginSymbol for sections with ",unique" linkage.

Reviewed By: grimar, jhenderson

Differential Revision: https://reviews.llvm.org/D92151
2020-11-26 09:13:09 -08:00
Fangrui Song
6b14814e10 [AsmPrinter] Omit unique ID for .stack_sizes
Follow-up for D74006.
2020-02-14 21:25:06 -08:00
George Rimar
dcf59c5480 Recommit r335333 "[MC] - Add .stack_size sections into groups and link them with .text"
With compilation fix.

Original commit message:

D39788 added a '.stack-size' section containing metadata on function stack sizes
to output ELF files behind the new -stack-size-section flag.

This change does following two things on top:

1) Imagine the case when there are -ffunction-sections flag given and there are text sections in COMDATs. 
    The patch adds a '.stack-size' section into corresponding COMDAT group, so that linker will be able to
    eliminate them fast during resolving the COMDATs.
2) Patch sets a SHF_LINK_ORDER flag and links '.stack-size' with the corresponding .text.
   With that linker will be able to do -gc-sections on dead stack sizes sections.

Differential revision: https://reviews.llvm.org/D46874

llvm-svn: 335336
2018-06-22 10:53:47 +00:00
George Rimar
6d448da1be Revert r335332 "[MC] - Add .stack_size sections into groups and link them with .text"
It broke bots.

http://lab.llvm.org:8011/builders/clang-ppc64le-linux-lnt/builds/12891
http://lab.llvm.org:8011/builders/clang-cmake-x86_64-sde-avx512-linux/builds/9443
http://lab.llvm.org:8011/builders/lldb-x86_64-ubuntu-14.04-buildserver/builds/25551

llvm-svn: 335333
2018-06-22 10:27:33 +00:00
George Rimar
e14485a0c6 [MC] - Add .stack_size sections into groups and link them with .text
D39788 added a '.stack-size' section containing metadata on function stack sizes
to output ELF files behind the new -stack-size-section flag.

This change does following two things on top:

1) Imagine the case when there are -ffunction-sections flag given and there are text sections in COMDATs. 
    The patch adds a '.stack-size' section into corresponding COMDAT group, so that linker will be able to
    eliminate them fast during resolving the COMDATs.
2) Patch sets a SHF_LINK_ORDER flag and links '.stack-size' with the corresponding .text.
   With that linker will be able to do -gc-sections on dead stack sizes sections.

Differential revision: https://reviews.llvm.org/D46874

llvm-svn: 335332
2018-06-22 10:10:53 +00:00