Commit Graph

6 Commits

Author SHA1 Message Date
Peter Collingbourne a0f371a106 Bitcode: Add a string table to the bitcode format.
Add a top-level STRTAB block containing a string table blob, and start storing
strings for module codes FUNCTION, GLOBALVAR, ALIAS, IFUNC and COMDAT in
the string table.

This change allows us to share names between globals and comdats as well
as between modules, and improves the efficiency of loading bitcode files by
no longer using a bit encoding for symbol names. Once we start writing the
irsymtab to the bitcode file we will also be able to share strings between
it and the module.

On my machine, link time for Chromium for Linux with ThinLTO decreases by
about 7% for no-op incremental builds or about 1% for full builds. Total
bitcode file size decreases by about 3%.

As discussed on llvm-dev:
http://lists.llvm.org/pipermail/llvm-dev/2017-April/111732.html

Differential Revision: https://reviews.llvm.org/D31838

llvm-svn: 300464
2017-04-17 17:51:36 +00:00
Mehdi Amini e2770c0b80 Fix test change in r290736: restore index generation
I remove one extra line, but because annoyingly llvm-lit does not
clean the output directory before running the test, it didn't fail
locally (the file was present from a previous run).

llvm-svn: 290740
2016-12-30 01:15:50 +00:00
Mehdi Amini 30a9b6bb4e Replace test from using llvm-lto to use llvm-link (NFC)
Some incoming changes in ThinLTO will break this test.
Instead of relying on the heuristic to import, we
force the importing to happen with llvm-link.

llvm-svn: 290736
2016-12-30 00:45:26 +00:00
Mehdi Amini a71002e7f1 Fix bitcode auto-upgrade when using bitcode lazy loading
The auto-upgrade path could be called before the VST (global
names) was fully parsed, and thus intrinsic names were not
available and the autoupgrade logic could not operate.

Fix link failures with ThinLTO.

This is a recommit of r278610 with a different fix.

llvm-svn: 278615
2016-08-14 00:01:27 +00:00
Mehdi Amini 466a64e298 Revert "Fix bitcode auto-upgrade when using bitcode lazy loading"
This reverts commit r278610. Tests are broken

llvm-svn: 278613
2016-08-13 23:39:14 +00:00
Mehdi Amini e62aaf2303 Fix bitcode auto-upgrade when using bitcode lazy loading
The auto-upgrade path could be called before the VST (global
names) was fully parsed, and thus intrinsic names were not
available and the autoupgrade logic could not operate.

Fix link failures with ThinLTO.

llvm-svn: 278610
2016-08-13 23:31:53 +00:00