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.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@253436 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
Now that there is a one-to-one mapping from MachineFunction to
WinEHFuncInfo, we don't need to use a DenseMap to select the right
WinEHFuncInfo for the current funclet.
The main challenge here is that X86WinEHStatePass is an IR pass that
doesn't have access to the MachineFunction. I gave it its own
WinEHFuncInfo object that it uses to calculate state numbers, which it
then throws away. As long as nobody creates or removes EH pads between
this pass and SDAG construction, we will get the same state numbers.
The other thing X86WinEHStatePass does is to mark the EH registration
node. Instead of communicating which alloca was the registration through
WinEHFuncInfo, I added the llvm.x86.seh.ehregnode intrinsic. This
intrinsic generates no code and simply marks the alloca in use.
Reviewers: JCTremoulet
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D14668
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@253378 91177308-0d34-0410-b5e6-96231b3b80d8
The underlying issues surrounding codegen for 32-bit vselects have been resolved. The pessimistic costs for 64-bit vselects remain due to the bad
scalarization that is still happening there.
I tested this on A57 in T32, A32 and A64 modes. I saw no regressions, and some improvements.
From my benchmarks, I saw these improvements in A57 (T32)
spec.cpu2000.ref.177_mesa 5.95%
lnt.SingleSource/Benchmarks/Shootout/strcat 12.93%
lnt.MultiSource/Benchmarks/MiBench/telecomm-CRC32/telecomm-CRC32 11.89%
I also measured A57 A32, A53 T32 and A9 T32 and found no performance regressions. I see much bigger wins in third-party benchmarks with this change
Differential Revision: http://reviews.llvm.org/D14743
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@253349 91177308-0d34-0410-b5e6-96231b3b80d8
SELECT_CC has the nasty property of having operands with unrelated
types. So if you do something like:
f32 = select_cc f16, f16, f32, f32, cc
You'd only look for the action for <select_cc, f32>, but never f16.
If the types are all legal, but the op isn't (as for f16 on AArch64,
or for f128 on x86_64/AArch64?), then you get into trouble.
For f128, we have softenSetCCOperands to handle this case.
Similarly, for f16, we can directly promote the CC operands.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@253344 91177308-0d34-0410-b5e6-96231b3b80d8
Currently, if the assembler encounters an error after parsing (such as an
out-of-range fixup), it reports this as a fatal error, and so stops after the
first error. However, for most of these there is an obvious way to recover
after emitting the error, such as emitting the fixup with a value of zero. This
means that we can report on all of the errors in a file, not just the first
one. MCContext::reportError records the fact that an error was encountered, so
we won't actually emit an object file with the incorrect contents.
Differential Revision: http://reviews.llvm.org/D14717
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@253328 91177308-0d34-0410-b5e6-96231b3b80d8
The way prelink used to work was
* The compiler decides if a given section only has relocations that
are know to point to the same DSO. If so, it names it
.data.rel.ro.local<something>.
* The static linker puts all of these together.
* The prelinker program assigns addresses to each library and resolves
the local relocations.
There are many problems with this:
* It is incompatible with address space randomization.
* The information passed by the compiler is redundant. The linker
knows if a given relocation is in the same DSO or not. If could sort
by that if so desired.
* There are newer ways of speeding up DSO (gnu hash for example).
* Even if we want to implement this again in the compiler, the previous
implementation is pretty broken. It talks about relocations that are
"resolved by the static linker". If they are resolved, there are none
left for the prelinker. What one needs to track is if an expression
will require only dynamic relocations that point to the same DSO.
At this point it looks like the prelinker is an historical curiosity.
For example, fedora has retired it because it failed to build for two
releases
(http://pkgs.fedoraproject.org/cgit/prelink.git/commit/?id=eb43100a8331d91c801ee3dcdb0a0bb9babfdc1f)
This patch removes support for it. That is, it stops printing the
".local" sections.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@253280 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
Previously return type information for a function was derived from
return dag nodes. But this didn't work for dags with != return node. So
instead compute it directly from the LLVM function as is done for imports.
Differential Revision: http://reviews.llvm.org/D14593
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@253251 91177308-0d34-0410-b5e6-96231b3b80d8
On top of that, don't bother allocating and initializing UnwindHelp if
we don't have any funclets. Currently we always use RBP as our frame
pointer when funclets are present, so this change makes it impossible to
come here without any fixed stack objects.
Fixes PR25533.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@253245 91177308-0d34-0410-b5e6-96231b3b80d8
Function ARMConstantIslands::doInitialJumpTablePlacement() iterates over all
basic blocks in a machine function. It calls `MI = MBB.getLastNonDebugInstr()`
to get the last instruction in each block and then uses MI->getOpcode() to
decide what to do. If getLastNonDebugInstr() returns MBB.end() (for example,
when the block does not contain any instructions) then calling getOpcode() on
this value is incorrect. Avoid this problem by checking the result of
getLastNonDebugInstr().
Differential Revision: http://reviews.llvm.org/D14694
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@253222 91177308-0d34-0410-b5e6-96231b3b80d8
Storing the source location of the expression that created a constant pool
entry allows us to emit better error messages if we later discover that the
expression cannot be represented by a relocation.
Differential Revision: http://reviews.llvm.org/D14646
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@253220 91177308-0d34-0410-b5e6-96231b3b80d8
The MCValue class can store a SMLoc to allow better error messages to be
emitted if an error is detected after parsing. The ARM and AArch64 assembly
parsers were not setting this, so error messages did not have source
information.
Differential Revision: http://reviews.llvm.org/D14645
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@253219 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
* ARMv6KZ is the "canonical" name, given in the ARMARM
* ARMv6Z is an "official abbreviation" for it, mentioned in the ARMARM
* ARMv6ZK is a popular misspelling, which we should support as an alias.
The patch corrects the handling of the names.
Functional changes:
* ARMv6Z no longer treated as an architecture in its own right
* ARMv6ZK renamed to ARMv6KZ, accepting ARMv6ZK as an alias
* arm1176jz-s and arm1176jzf-s recognized as ARMv6ZK, instead of ARMv6K
* default ARMv6K CPU changed to arm1176j-s
Reviewers: rengolin, logan, compnerd
Subscribers: aemerson, llvm-commits, rengolin
Differential Revision: http://reviews.llvm.org/D14568
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@253206 91177308-0d34-0410-b5e6-96231b3b80d8
This allows for accurate architecture targeting as well as removing
duplicate information (hardcoded feature strings) from MCTargetDesc.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@253196 91177308-0d34-0410-b5e6-96231b3b80d8
This was left implicit and never ever checked, which means we could have a CMPZ against some non-zero value and we were carrying on with BFI conversion regardless.
Caught by Oliver Stannard using csmith; regression test added.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@253195 91177308-0d34-0410-b5e6-96231b3b80d8
The AArch64 assembler was silently ignoring instructions like this:
ldr foo, =bar
AArch64AsmParser::parseOperand was returning true as the parse failed, but was
not calling AArch64AsmParser::Error to report this to the user, so the
instruction was ignored without printing an error message.
Differential Revision: http://reviews.llvm.org/D14651
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@253193 91177308-0d34-0410-b5e6-96231b3b80d8
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
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@253127 91177308-0d34-0410-b5e6-96231b3b80d8
Darwin reserves x18, so it's never ABI compliant to generate code that
uses it. Set the default value based on the OS part of the triple
rather than forcing front-ends to set the +reserve-x18 target feature
in order to build correct code for Darwin.
This will make r243310 redundant, so I'll revert that shortly.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@253102 91177308-0d34-0410-b5e6-96231b3b80d8
The C++ EH personality automatically restores ESP from the C++ EH
registration node after a catchret. I mistakenly thought it was like
SEH, which does not restore ESP.
It makes sense for C++ EH to differ from SEH here because SEH does not
use funclets for catches, and does not allow catching inside of finally.
C++ EH may need to unwind through multiple catch funclets and eventually
catchret to some outer funclet. Therefore, the runtime has to keep track
of which ESP to use with catchret, rather than having the compiler
reload it manually.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@253084 91177308-0d34-0410-b5e6-96231b3b80d8
