Commit Graph

4 Commits

Author SHA1 Message Date
Rui Ueyama 3c45cffd68 Merge MutableFile with SimpleFile.
SimpleFile is the only derived class of MutableFile.
This patch reduces the height of class hierarchy by removing
MutableFile class.

llvm-svn: 234354
2015-04-07 20:43:38 +00:00
Rui Ueyama 33ab83bc4b ELF: Don't use LayoutPass.
Previously we applied the LayoutPass to order atoms and then
apply elf::ArrayOrderPass to sort them again. The first pass is
basically supposed to sort atoms in the normal fashion (which
is to sort symbols in the same order as the input files).
The second pass sorts atoms in {init,fini}_array.<priority> by
priority.

The problem is that the LayoutPass is overkill. It analyzes
references between atoms to make a decision how to sort them.
It's slow, hard to understand, and above all, it doesn't seem
that we need its feature for ELF in the first place.

This patch remove the LayoutPass from ELF pass list. Now all
reordering is done in elf::OrderPass. That pass sorts atoms by
{init,fini}_array, and if they are not in the special section,
they are ordered as the same order as they appear in the command
line. The new code is far easier to understand, faster, and
still able to create valid executables.

Unlike the previous layout pass, elf::OrderPass doesn't count
any attributes of an atom (e.g. permissions) except its
position. It's OK because the writer takes care of them if we
have to.

This patch changes the order of final output, although that's
benign. Tests are updated.

http://reviews.llvm.org/D7278

llvm-svn: 227666
2015-01-31 02:05:01 +00:00
Rui Ueyama c10c4c9d9b Add an assert to check atom ordinal.
No two atoms are allowed to have the same file and atom ordinals.
If there's such atoms, there's a bug in the reader.

llvm-svn: 227504
2015-01-29 22:39:43 +00:00
Rui Ueyama c4038ab5bf PECOFF: Do not use LayoutPass and instead use simpler one.
The LayoutPass is one of the slowest pass. This change is to skip
that pass. This change not only improve performance but also improve
maintainability of the code because the LayoutPass is pretty complex.

Previously we used the LayoutPass to sort all atoms in a specific way,
and reorder them again for PE/COFF in GroupedSectionPass.

I spent time on improving and fixing bugs in the LayoutPass (e.g.
r193029), but the pass is still hard to understand and hard to use.
It's better not to depend on that if we don't need. For PE/COFF, we
just wanted to sort atoms in the same order as the file order in the
command line.

The feature we used in the LayoutPass is now simplified to
compareByPosition function in OrderPass.cpp. The function is just 5
lines.

This patch changes the order of final output because it changes the
sort order a bit. The output is still correct, though.

llvm-svn: 227500
2015-01-29 22:12:50 +00:00