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
It isn't actually used now, and probably never will be, plus it makes
tests less annoying. I also think SC prints GDS instructions as a
separate instruction name.
llvm-svn: 204270
For functions where esi is used as base pointer, we would previously fall back
from lowering memcpy with "rep movs" because that clobbers esi.
With this patch, we just store esi in another physical register, and restore
it afterwards. This adds a little bit of register preassure, but the more
efficient memcpy should be worth it.
Differential Revision: http://llvm-reviews.chandlerc.com/D2968
llvm-svn: 204174
Summary:
X86BaseInfo.h defines an enum for the offset of each operand in a memory operand
sequence. Some code uses it and some does not. This patch replaces (hopefully)
all remaining locations where an integer literal was used instead of this enum.
No functionality change intended.
Reviewers: nadav
CC: llvm-commits, t.p.northover
Differential Revision: http://llvm-reviews.chandlerc.com/D3108
llvm-svn: 204158
When converting a signed 32-bit integer to double-precision floating point on
hardware without a lfiwax instruction, we have to instead use a lfd followed
by fcfid. We were erroneously offsetting the address by 4 bytes in
preparation for either a lfiwax or lfiwzx when generating the lfd. This fixes
that silly error.
This was not caught in the test suite since the conversion tests were run with
-mcpu=pwr7, which implies availability of lfiwax. I've added another test
case for older hardware that checks the code we expect in the absence of
lfiwax and other flavors of fcfid. There are fewer tests in this test case
because we punt to DAG selection in more cases on older hardware. (We must
generate complex fiddly sequences in those cases, and there is marginal
benefit in duplicating that logic in fast-isel.)
llvm-svn: 204155
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
Rather than LegalizeAction::Expand, this needs LegalizeAction::Promote to get
promoted to fp_to_sint v8f32->v8i32. This is a legal operation on AVX.
For that to work properly, we also need to teach the legalizer about the
specific promotion required here. The default vector promotion uses
bitcasting to a vector type of the same total size. We want to promote the
vector element type, effectively widening the operation and then truncating
the result. This is analogous to the current logic of how int_to_fp is
promoted.
The change also factors out some code from the int_to_fp promotion code to
ValueType::widenIntegerVectorElementType. This is now shared between
int_to_fp and fp_to_int.
There is no longer need for the custom lowering of fp_to_sint f32->v8i16 in
X86. It can now go through the new target-independent fp_to_*int promotion
logic.
I also checked that no other target uses Promote for these ops yet, so there
shouldn't be any unexpected change in behavior.
Fixes <rdar://problem/16202247>
llvm-svn: 204058
The type of the immediates should not matter as long as the encoding is
equivalent to the encoding of one of the legal inline constants.
Tested-by: Michel Dänzer <michel.daenzer@amd.com>
llvm-svn: 204056
This instructions writes to an 32-bit SGPR. This change required adding
the 32-bit VCC_LO and VCC_HI registers, because the full VCC register
is 64 bits.
This fixes verifier errors on several of the indirect addressing piglit
tests.
Tested-by: Michel Dänzer <michel.daenzer@amd.com>
llvm-svn: 204055
- Adds support for inserting vzerouppers before tail-calls.
This is enabled implicitly by having MachineInstr::copyImplicitOps preserve
regmask operands, which allows VZeroUpperInserter to see where tail-calls use
vector registers.
- Fixes a bug that caused the previous version of this optimization to miss some
vzeroupper insertion points in loops. (Loops-with-vector-code that followed
loops-without-vector-code were mistakenly overlooked by the previous version).
- New algorithm never revisits instructions.
Fixes <rdar://problem/16228798>
llvm-svn: 204021
Utilize the previous move of MVT to a separate header for all trivial
cases (that don't need any further restructuring).
Reviewed By: Tim Northover
llvm-svn: 204003
This change brings getCallPreservedMask()'s logic in line with
getCalleeSavedRegs().
While this changes the control flow slightly, the change is not
currently observable. is64Bit must be false to get to the accidental
fallthrough, but the case that we fall into (coldcc) does nothing unless
is64Bit is true.
llvm-svn: 203943
Commit r181723 introduced code to avoid placing initialized variables
needing relocations into the .rodata section, which avoid copy relocs
that do not work as expected on ppc64 function references.
The same treatment is also needed for *named* .rodata.XXX sections.
This patch changes PPC64LinuxTargetObjectFile::SelectSectionForGlobal
to modify "Kind" *before* calling the default SelectSectionForGlobal
routine, instead of first calling the default routine and then just
checking for the (main) .rodata section afterwards.
llvm-svn: 203921
These linkages were introduced some time ago, but it was never very
clear what exactly their semantics were or what they should be used
for. Some investigation found these uses:
* utf-16 strings in clang.
* non-unnamed_addr strings produced by the sanitizers.
It turns out they were just working around a more fundamental problem.
For some sections a MachO linker needs a symbol in order to split the
section into atoms, and llvm had no idea that was the case. I fixed
that in r201700 and it is now safe to use the private linkage. When
the object ends up in a section that requires symbols, llvm will use a
'l' prefix instead of a 'L' prefix and things just work.
With that, these linkages were already dead, but there was a potential
future user in the objc metadata information. I am still looking at
CGObjcMac.cpp, but at this point I am convinced that linker_private
and linker_private_weak are not what they need.
The objc uses are currently split in
* Regular symbols (no '\01' prefix). LLVM already directly provides
whatever semantics they need.
* Uses of a private name (start with "\01L" or "\01l") and private
linkage. We can drop the "\01L" and "\01l" prefixes as soon as llvm
agrees with clang on L being ok or not for a given section. I have two
patches in code review for this.
* Uses of private name and weak linkage.
The last case is the one that one could think would fit one of these
linkages. That is not the case. The semantics are
* the linker will merge these symbol by *name*.
* the linker will hide them in the final DSO.
Given that the merging is done by name, any of the private (or
internal) linkages would be a bad match. They allow llvm to rename the
symbols, and that is really not what we want. From the llvm point of
view, these objects should really be (linkonce|weak)(_odr)?.
For now, just keeping the "\01l" prefix is probably the best for these
symbols. If we one day want to have a more direct support in llvm,
IMHO what we should add is not a linkage, it is just a hidden_symbol
attribute. It would be applicable to multiple linkages. For example,
on weak it would produce the current behavior we have for objc
metadata. On internal, it would be equivalent to private (and we
should then remove private).
llvm-svn: 203866
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 changes the implementation of local directional labels to use a dedicated
map. With that it can then just use CreateTempSymbol, which is what the rest
of MC uses.
CreateTempSymbol doesn't do a great job at making sure the names are unique
(or being efficient when the names are not needed), but that should probably
be fixed in a followup patch.
This fixes pr18928.
llvm-svn: 203826
LDS instructions are pseudo instructions which model
the OQAP defs and uses within a single instruction.
This fixes a hang in the opencv MedianFilter tests.
llvm-svn: 203818
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
Zoran Jovanovic