Given
bar = foo + 4
.long bar
MC would eat the 4. GNU as includes it in the relocation. The rule seems to be
that a variable that defines a symbol is used in the relocation and one that
does not define a symbol is evaluated and the result included in the relocation.
Fixing this unfortunately required some other changes:
* Since the variable is now evaluated, it would prevent the ELF writer from
noticing the weakref marker the elf streamer uses. This patch then replaces
that with a VariantKind in MCSymbolRefExpr.
* Using VariantKind then requires us to look past other VariantKind to see
.weakref bar,foo
call bar@PLT
doing this also fixes
zed = foo +2
call zed@PLT
so that is a good thing.
* Looking past VariantKind means that the relocation selection has to use
the fixup instead of the target.
This is a reboot of the previous fixes for MC. I will watch the sanitizer
buildbot and wait for a build before adding back the previous fixes.
llvm-svn: 204294
The revision I'm reverting breaks handling of transitive aliases. This blocks us
and breaks sanitizer bootstrap:
http://lab.llvm.org:8011/builders/sanitizer-x86_64-linux-bootstrap/builds/2651
(and checked locally by Alexey).
This revision is the result of:
svn merge -r204059:204058 -r204028:204027 -r203962:203961 .
+ the regression test added to test/MC/ELF/alias.s
Another way to reproduce the regression with clang:
$ cat q.c
void a1();
void a2() __attribute__((alias("a1")));
void a3() __attribute__((alias("a2")));
void a1() {}
$ ~/work/llvm-build/bin/clang-3.5-good -c q.c && mv q.o good.o && \
~/work/llvm-build/bin/clang-3.5-bad -c q.c && mv q.o bad.o && \
objdump -t good.o bad.o
good.o: file format elf64-x86-64
SYMBOL TABLE:
0000000000000000 l df *ABS* 0000000000000000 q.c
0000000000000000 l d .text 0000000000000000 .text
0000000000000000 l d .data 0000000000000000 .data
0000000000000000 l d .bss 0000000000000000 .bss
0000000000000000 l d .comment 0000000000000000 .comment
0000000000000000 l d .note.GNU-stack 0000000000000000 .note.GNU-stack
0000000000000000 l d .eh_frame 0000000000000000 .eh_frame
0000000000000000 g F .text 0000000000000006 a1
0000000000000000 g F .text 0000000000000006 a2
0000000000000000 g F .text 0000000000000006 a3
bad.o: file format elf64-x86-64
SYMBOL TABLE:
0000000000000000 l df *ABS* 0000000000000000 q.c
0000000000000000 l d .text 0000000000000000 .text
0000000000000000 l d .data 0000000000000000 .data
0000000000000000 l d .bss 0000000000000000 .bss
0000000000000000 l d .comment 0000000000000000 .comment
0000000000000000 l d .note.GNU-stack 0000000000000000 .note.GNU-stack
0000000000000000 l d .eh_frame 0000000000000000 .eh_frame
0000000000000000 g F .text 0000000000000006 a1
0000000000000000 g F .text 0000000000000006 a2
0000000000000000 g .text 0000000000000000 a3
llvm-svn: 204137
Add an assertion that a valid section is referenced. The potential NULL pointer
dereference was identified by the clang static analyzer.
llvm-svn: 204114
This performs the equivalent of a .set directive in that it creates a symbol
which is an alias for another symbol or value which may possibly be yet
undefined. This directive also has the added property in that it marks the
aliased symbol as being a thumb function entry point, in the same way that the
.thumb_func directive does.
The current implementation fails one test due to an unrelated issue. Functions
within .thumb sections are not marked as thumb_func. The result is that
the aliasee function is not valued correctly.
llvm-svn: 204059
operator* on the by-operand iterators to return a MachineOperand& rather than
a MachineInstr&. At this point they almost behave like normal iterators!
Again, this requires making some existing loops more verbose, but should pave
the way for the big range-based for-loop cleanups in the future.
llvm-svn: 203865
This is a follow-up to r203635. Saleem pointed out that since symbolic register
names are much easier to read, it would be good if we could turn them off only
when we really need to because we're using an external assembler.
Differential Revision: http://llvm-reviews.chandlerc.com/D3056
llvm-svn: 203806
Support to the IAS was added to actually parse and handle the complex SO
expressions. However, the object file lowering was not updated to compensate
for the fact that the shift operand may be an absolute expression.
When trying to assemble to an object file, the lowering would fail while
succeeding when emitting purely assembly. Add an appropriate test.
The test case is inspired by the test case provided by Jiangning Liu who also
brought the issue to light.
llvm-svn: 203762
When the list of VFP registers to be saved was non-contiguous (so multiple
vpush/vpop instructions were needed) these were being ordered oddly, as in:
vpush {d8, d9}
vpush {d11}
This led to the layout in memory being [d11, d8, d9] which is ugly and doesn't
match the CFI_INSTRUCTIONs we're generating either (so Dwarf info would be
broken).
This switches the order of vpush/vpop (in both prologue and epilogue,
obviously) so that the Dwarf locations are correct again.
rdar://problem/16264856
llvm-svn: 203655
It seems gas can't handle CFI directives with VFP register names ("d12", etc.).
This broke us trying to build Chromium for Android after 201423.
A gas bug has been filed: https://sourceware.org/bugzilla/show_bug.cgi?id=16694
compnerd suggested making this conditional on whether we're using the integrated
assembler or not. I'll look into that in a follow-up patch.
Differential Revision: http://llvm-reviews.chandlerc.com/D3049
llvm-svn: 203635
Use the options in the ARMISelLowering to control whether tail calls are
optimised or not. Previously, this option was entirely ignored on the ARM
target and only honoured on x86.
This option is mostly useful in profiling scenarios. The default remains that
tail call optimisations will be applied.
llvm-svn: 203577
This option is from 2010, designed to work around a linker issue on Darwin for
ARM. According to grosbach this is no longer an issue and this option can
safely be removed.
llvm-svn: 203576
Tail call optimisation was previously disabled on all targets other than
iOS5.0+. This enables the tail call optimisation on all Thumb 2 capable
platforms.
The test adjustments are to remove the IR hint "tail" to function invocation.
The tests were designed assuming that tail call optimisations would not kick in
which no longer holds true.
llvm-svn: 203575
ATOMIC_STORE operations always get here as a lowered ATOMIC_SWAP, so there's no
need for any code to handle them specially.
There should be no functionality change so no tests.
llvm-svn: 203567
The syntax for "cmpxchg" should now look something like:
cmpxchg i32* %addr, i32 42, i32 3 acquire monotonic
where the second ordering argument gives the required semantics in the case
that no exchange takes place. It should be no stronger than the first ordering
constraint and cannot be either "release" or "acq_rel" (since no store will
have taken place).
rdar://problem/15996804
llvm-svn: 203559
the stack of the analysis group because they are all immutable passes.
This is made clear by Craig's recent work to use override
systematically -- we weren't overriding anything for 'finalizePass'
because there is no such thing.
This is kind of a lame restriction on the API -- we can no longer push
and pop things, we just set up the stack and run. However, I'm not
invested in building some better solution on top of the existing
(terrifying) immutable pass and legacy pass manager.
llvm-svn: 203437
Summary:
llvm/MC/MCSectionMachO.h and llvm/Support/MachO.h both had the same
definitions for the section flags. Instead, grab the definitions out of
support.
No functionality change.
Reviewers: grosbach, Bigcheese, rafael
Reviewed By: rafael
CC: llvm-commits
Differential Revision: http://llvm-reviews.chandlerc.com/D2998
llvm-svn: 203211
The old system was fairly convoluted:
* A temporary label was created.
* A single PROLOG_LABEL was created with it.
* A few MCCFIInstructions were created with the same label.
The semantics were that the cfi instructions were mapped to the PROLOG_LABEL
via the temporary label. The output position was that of the PROLOG_LABEL.
The temporary label itself was used only for doing the mapping.
The new CFI_INSTRUCTION has a 1:1 mapping to MCCFIInstructions and points to
one by holding an index into the CFI instructions of this function.
I did consider removing MMI.getFrameInstructions completelly and having
CFI_INSTRUCTION own a MCCFIInstruction, but MCCFIInstructions have non
trivial constructors and destructors and are somewhat big, so the this setup
is probably better.
The net result is that we don't create temporary labels that are never used.
llvm-svn: 203204
This is a preliminary setup change to support a renaming of Windows target
triples. Split the object file format information out of the environment into a
separate entity. Unfortunately, file format was previously treated as an
environment with an unknown OS. This is most obvious in the ARM subtarget where
the handling for macho on an arbitrary platform switches to AAPCS rather than
APCS (as per Apple's needs).
llvm-svn: 203160
name might indicate, it is an iterator over the types in an instruction
in the IR.... You see where this is going.
Another step of modularizing the support library.
llvm-svn: 202815
This is a temporary workaround for native arm linux builds:
PR18996: Changing regalloc order breaks "lencod" on native arm linux builds.
llvm-svn: 202433
scan the register file for sub- and super-registers.
No functionality change intended.
(Tests are updated because the comments in the assembler output are
different.)
llvm-svn: 202416
Saleem Abdulrasool