Commit Graph

5 Commits

Author SHA1 Message Date
Rafael Espindola
9f299abc05 Omit unused section symbols from the symbol table.
Section symbols exist as an optimization: instead of having multiple relocations
point to different symbols, many of them can point to a single section symbol.

When that optimization is unused, a section symbol is also unused and adds no
extra information to the object file.

This saves a bit of space on the object files and makes the output of
llvm-objdump -t easier to read and consequently some tests get quite a bit
simpler.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@239045 91177308-0d34-0410-b5e6-96231b3b80d8
2015-06-04 15:33:30 +00:00
Rafael Espindola
201a551929 Fix the interpretation of a 0 st_name.
The ELF spec is very clear:

-----------------------------------------------------------------------------
If the value is non-zero, it represents a string table index that gives the
symbol name. Otherwise, the symbol table entry has no name.
--------------------------------------------------------------------------

In particular, a st_name of 0 most certainly doesn't mean that the symbol has
the same name as the section.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@238899 91177308-0d34-0410-b5e6-96231b3b80d8
2015-06-03 05:14:22 +00:00
Rafael Espindola
76e71bd66e Write sections mostly in one pass.
During ELF writing, there is no need to further relax the sections, so we
should not be creating fragments. This patch avoids doing so in all cases
but debug section compression (that is next).

Also, the ELF format is fairly simple to write. We can do a single pass over
the sections to write them out and compute the section header table.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@236235 91177308-0d34-0410-b5e6-96231b3b80d8
2015-04-30 14:21:49 +00:00
Rafael Espindola
58a854d447 Write the section header string table directly to the output stream.
Instead of accumulating the content in a fragment first, just write it
to the output stream.

Also put it first in the section table, so that we never have to worry
about its index being >= SHN_LORESERVE.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@236145 91177308-0d34-0410-b5e6-96231b3b80d8
2015-04-29 20:25:24 +00:00
David Blaikie
2b3ea3cdad MC: Support multiple sections with the same name in the same comdat group
Code review by Eric Christopher and Rafael Espindola.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@193209 91177308-0d34-0410-b5e6-96231b3b80d8
2013-10-22 23:41:52 +00:00