actuall addresses in a .o file, so it is better to let the MachO writer compute
it.
This is good for two reasons. First, areas that shouldn't care about
addresses now don't have access to it. Second, the layout of each section
is independent. I should use this in a subsequent commit to speed it up.
Most of the patch is just removing the section address computation. The two
interesting parts are the change on how we handle padding in the end
of sections and how MachO can get the address of a-b when a and b are in
different sections.
Since now the expression evaluation normally doesn't know the section address,
it will think that a-b needs relocation and let the MachO writer know. Once
it has computed the section addresses, it calls back the expression evaluation
with the section addresses to resolve these expressions.
The remaining problem is the handling of padding. Currently it will create
a special alignment fragment at the end. Since that fragment doesn't update
the alignment of the section, it needs the real address to be computed.
Since now the layout will not compute a-b with a and b in different sections,
the only effect that the special alignment fragment has is update the
address size of the section. This can also be done by the MachO writer.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@121076 91177308-0d34-0410-b5e6-96231b3b80d8
contain only data. Handle them specially instead of using AddSectionToTheEnd.
This moves a hack from the generic assembler to the elf writer. It is also
a bit faster and should make other improvements easier.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@120683 91177308-0d34-0410-b5e6-96231b3b80d8
// FIXME: We should compute this sooner, we don't want to recurse here, and
// we would like to be more functional.
In MCAssembler::ComputeFragmentSize.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@118080 91177308-0d34-0410-b5e6-96231b3b80d8
resolved or not. Different object files have different restrictions and
different native assemblers have different idiosyncrasies we want to emulate
for now.
Move the existing MachO logic to the new place and implement an ELF one that
gets fixups to globals right.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@115131 91177308-0d34-0410-b5e6-96231b3b80d8
Introduce a helper method to add a section to the end of a layout. This
will be used by the ELF ObjectWriter code to add the metadata sections
(symbol table, etc) to the end of an object file.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@111171 91177308-0d34-0410-b5e6-96231b3b80d8
- This eliminates getAtomForAddress() (which was a linear search) and
simplifies getAtom().
- This also fixes some correctness problems where local labels at the same
address as non-local labels could be assigned to the wrong atom.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@103480 91177308-0d34-0410-b5e6-96231b3b80d8
exactly two passes in that case, and don't ever need to recompute any layout,
so this is a nice baseline for relaxation performance.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@99563 91177308-0d34-0410-b5e6-96231b3b80d8
- Still O(N^2), just a faster form, and now its the MCAsmLayout's fault.
On the .s I am tuning against (combine.s from 403.gcc):
--
ddunbar@lordcrumb:MC$ diff stats-before.txt stats-after.txt
5,10c5,10
< 1728 assembler - Number of assembler layout and relaxation steps
< 7707 assembler - Number of emitted assembler fragments
< 120588 assembler - Number of emitted object file bytes
< 2233448 assembler - Number of evaluated fixups
< 1727 assembler - Number of relaxed instructions
< 6723845 mcexpr - Number of MCExpr evaluations
---
> 3 assembler - Number of assembler layout and relaxation steps
> 7707 assembler - Number of emitted assembler fragments
> 120588 assembler - Number of emitted object file bytes
> 14796 assembler - Number of evaluated fixups
> 1727 assembler - Number of relaxed instructions
> 67889 mcexpr - Number of MCExpr evaluations
--
Feel free to LOL at the -before numbers, if you like.
I am a little surprised we make more than 2 relaxation passes. It's pretty
trivial for us to do relaxation out-of-order if that would give a speedup.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@99543 91177308-0d34-0410-b5e6-96231b3b80d8
