This is an improvement when compiling with llvm. llvm doesn't inline
the call to insert, so the align is always executed and shows up in
the profile.
With gcc the call to insert is inlined and the align computation moved
and done only if needed.
With this patch we explicitly only compute it if it is needed.
In the two tests with debug info, the speedup was
scylla
master 3.008959365
patch 2.932080942 1.02621974786x faster
firefox
master 6.709823604
patch 6.592387227 1.01781393795x faster
In all others the difference was in the noise.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@284249 91177308-0d34-0410-b5e6-96231b3b80d8
This change seems to speed up LLD a bit if it has a lot of mergeable
sections. The number is below. It's not too bad for a small patch.
Time to link Clang (debug build):
w/o patch 6.3696 seconds
w/patch 6.2746 seconds (-1.5%)
Differential Revision: http://reviews.llvm.org/D19933
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@268698 91177308-0d34-0410-b5e6-96231b3b80d8
This reverts commit r259117.
The LineInfo constructor is defined in the codeview library and we have
to link against it now. Doing that isn't trivial, so reverting for now.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@259126 91177308-0d34-0410-b5e6-96231b3b80d8
Adds a new family of .cv_* directives to LLVM's variant of GAS syntax:
- .cv_file: Similar to DWARF .file directives
- .cv_loc: Similar to the DWARF .loc directive, but starts with a
function id. CodeView line tables are emitted by function instead of
by compilation unit, so we needed an extra field to communicate this.
Rather than overloading the .loc direction further, we decided it was
better to have our own directive.
- .cv_stringtable: Emits the codeview string table at the current
position. Currently this just contains the filenames as
null-terminated strings.
- .cv_filechecksums: Emits the file checksum table for all files used
with .cv_file so far. There is currently no support for emitting
actual checksums, just filenames.
This moves the line table emission code down into the assembler. This
is in preparation for implementing the inlined call site line table
format. The inline line table format encoding algorithm requires knowing
the absolute code offsets, so it must run after the assembler has laid
out the code.
David Majnemer collaborated on this patch.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@259117 91177308-0d34-0410-b5e6-96231b3b80d8
This is a patch to improve StringTableBuilder's performance. That class'
finalize function is very hot particularly in LLD because the function
does tail-merge strings in string tables or SHF_MERGE sections.
Generic std::sort-style sorter is not efficient for sorting strings.
The function implemented in this patch seems to be more efficient.
Here's a benchmark of LLD to link Clang with or without this patch.
The numbers are medians of 50 runs.
-O0
real 0m0.455s
real 0m0.430s (5.5% faster)
-O3
real 0m0.487s
real 0m0.452s (7.2% faster)
Since that is a benchmark of the whole linker, the speedup of
StringTableBuilder itself is much more than that.
http://reviews.llvm.org/D14053
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@251337 91177308-0d34-0410-b5e6-96231b3b80d8
In this mode it just tries to tail merge the strings without imposing any other
format constrains. It will not, for example, add a null byte between them.
Also add support for keeping a tentative size and offset if we decide to
not optimize after all.
This will be used shortly in lld for merging SHF_STRINGS sections.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@251153 91177308-0d34-0410-b5e6-96231b3b80d8
Now that we have a lib/MC/MCAnalysis, the dependency was there just because
of two helper classes. Move the two over to MC.
This will allow IRObjectFile to parse inline assembly.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@212248 91177308-0d34-0410-b5e6-96231b3b80d8
