If a section is rw, it is irrelevant if the dynamic linker will write to
it or not.
It looks like llvm implemented this because gcc was doing it. It looks
like gcc implemented this in the hope that it would put all the
relocated items close together and speed up the dynamic linker.
There are two problem with this:
* It doesn't work. Both bfd and gold will map .data.rel to .data and
concatenate the input sections in the order they are seen.
* If we want a feature like that, it can be implemented directly in the
linker since it knowns where the dynamic relocations are.
llvm-svn: 253436
MCRelaxableFragment previously kept a copy of MCSubtargetInfo and
MCInst to enable re-encoding the MCInst later during relaxation. A copy
of MCSubtargetInfo (instead of a reference or pointer) was needed
because the feature bits could be modified by the parser.
This commit replaces the MCSubtargetInfo copy in MCRelaxableFragment
with a constant reference to MCSubtargetInfo. The copies of
MCSubtargetInfo are kept in MCContext, and the target parsers are now
responsible for asking MCContext to provide a copy whenever the feature
bits of MCSubtargetInfo have to be toggled.
With this patch, I saw a 4% reduction in peak memory usage when I
compiled verify-uselistorder.lto.bc using llc.
rdar://problem/21736951
Differential Revision: http://reviews.llvm.org/D14346
llvm-svn: 253127
MCSubtargetInfo in the subclasses into MCTargetAsmParser and define a
member function getSTI.
This is done in preparation for making changes to shrink the size of
MCRelaxableFragment. (see http://reviews.llvm.org/D14346).
llvm-svn: 253124
Summary:
The CLR's personality routine passes these in rdx/edx, not rax/eax.
Make getExceptionPointerRegister a virtual method parameterized by
personality function to allow making this distinction.
Similarly make getExceptionSelectorRegister a virtual method parameterized
by personality function, for symmetry.
Reviewers: pgavlin, majnemer, rnk
Subscribers: jyknight, dsanders, llvm-commits
Differential Revision: http://reviews.llvm.org/D14344
llvm-svn: 252383
Some implicit ilist iterator conversions have crept back into Analysis,
Transforms, Hexagon, and llvm-stress. This removes them.
I'll commit a patch immediately after this to disallow them (in a
separate patch so that it's easy to revert if necessary).
llvm-svn: 252371
There are two things out of the ordinary in this commit. First, I made
a loop obviously "infinite" in HexagonInstrInfo.cpp. After checking if
an instruction was at the beginning of a basic block (in which case,
`break`), the loop decremented and checked the iterator for `nullptr` as
the loop condition. This has never been possible (the prev pointers are
always been circular, so even with the weird ilist/iplist
implementation, this isn't been possible), so I removed the condition.
Second, in HexagonAsmPrinter.cpp there was another case of comparing a
`MachineBasicBlock::instr_iterator` against `MachineBasicBlock::end()`
(which returns `MachineBasicBlock::iterator`). While not incorrect,
it's fragile. I switched this to `::instr_end()`.
All that said, no functionality change intended here.
llvm-svn: 250778
- Isolate the check for the existence of a stack frame into hasFP.
- Implement getFrameIndexReference for DWARF address computation.
- Use getFrameIndexReference for offset computation in eliminateFrameIndex.
- Preserve debug information for dynamically allocated stack objects.
- Prefer FP to access local objects at -O0.
- Add experimental code to skip allocframe when not strictly necessary
(disabled by default).
llvm-svn: 250718
Emit the CFI instructions after all code transformation have been done.
This will avoid any interference between CFI instructions and packetization.
llvm-svn: 250714
This extends the work done in r233995 so that now getFragment (in addition to
getSection) also works for variable symbols.
With that the existing logic to decide if a-b can be computed works even if
a or b are variables. Given that, the expression evaluation can avoid expanding
variables as aggressively and that in turn lets the relocation code see the
original variable.
In order for this to work with the asm streamer, there is now a dummy fragment
per section. It is used to assign a section to a symbol when no other fragment
exists.
This patch is a joint work by Maxim Ostapenko andy myself.
llvm-svn: 249303
Rafael Espindola