Commit Graph

8 Commits

Author SHA1 Message Date
Joerg Sonnenberger 400e7b7811 Use PIC relocation model as default for PowerPC64 ELF.
Most of the PowerPC64 code generation for the ELF ABI is already PIC.
There are four main exceptions:
(1) Constant pointer arrays etc. should in writeable sections.
(2) The TOC restoration NOP after a call is needed for all global
symbols. While GNU ld has a workaround for questionable GCC self-calls,
we trigger the checks for calls from COMDAT sections as they cross input
sections and are therefore not considered self-calls. The current
decision is questionable and suboptimal, but outside the scope of the
change.
(3) TLS access can not use the initial-exec model.
(4) Jump tables should use relative addresses. Note that the current
encoding doesn't work for the large code model, but it is more compact
than the default for any non-trivial jump table. Improving this is again
beyond the scope of this change.

At least (1) and (3) are assumptions made in target-independent code and
introducing additional hooks is a bit messy. Testing with clang shows
that a -fPIC binary is 600KB smaller than the corresponding -fno-pic
build. Separate testing from improved jump table encodings would explain
only about 100KB or so. The rest is expected to be a result of more
aggressive immediate forming for -fno-pic, where the -fPIC binary just
uses TOC entries.

This change brings the LLVM output in line with the GCC output, other
PPC64 compilers like XLC on AIX are known to produce PIC by default
as well. The relocation model can still be provided explicitly, i.e.
when using MCJIT.

One test case for case (1) is included, other test cases with relocation
mode sensitive behavior are wired to static for now. They will be
reviewed and adjusted separately.

Differential Revision: https://reviews.llvm.org/D26566

llvm-svn: 289743
2016-12-15 00:01:53 +00:00
Ehsan Amiri a538b0f023 Adding -verify-machineinstrs option to PowerPC tests
Currently we have a number of tests that fail with -verify-machineinstrs.
To detect this cases earlier we add the option to the testcases with the
exception of tests that will currently fail with this option. PR 27456 keeps
track of this failures.

No code review, as discussed with Hal Finkel.

llvm-svn: 277624
2016-08-03 18:17:35 +00:00
Rafael Espindola 10f3de6889 Update tests to not be as dependent on section numbers.
Many of these predate llvm-readobj. With elf-dump we had to match
a relocation to symbol number and symbol number to symbol name or
section number.

llvm-svn: 235015
2015-04-15 15:59:37 +00:00
David Blaikie a79ac14fa6 [opaque pointer type] Add textual IR support for explicit type parameter to load instruction
Essentially the same as the GEP change in r230786.

A similar migration script can be used to update test cases, though a few more
test case improvements/changes were required this time around: (r229269-r229278)

import fileinput
import sys
import re

pat = re.compile(r"((?:=|:|^)\s*load (?:atomic )?(?:volatile )?(.*?))(| addrspace\(\d+\) *)\*($| *(?:%|@|null|undef|blockaddress|getelementptr|addrspacecast|bitcast|inttoptr|\[\[[a-zA-Z]|\{\{).*$)")

for line in sys.stdin:
  sys.stdout.write(re.sub(pat, r"\1, \2\3*\4", line))

Reviewers: rafael, dexonsmith, grosser

Differential Revision: http://reviews.llvm.org/D7649

llvm-svn: 230794
2015-02-27 21:17:42 +00:00
Hal Finkel 34974ed503 [PowerPC] Implement some additional TLI callbacks
Add implementations of:
  bool isLegalICmpImmediate(int64_t Imm) const
  bool isLegalAddImmediate(int64_t Imm) const
  bool isTruncateFree(Type *Ty1, Type *Ty2) const
  bool isTruncateFree(EVT VT1, EVT VT2) const
  bool shouldConvertConstantLoadToIntImm(const APInt &Imm, Type *Ty) const

Unfortunately, this regresses counter-register-based loop formation because
some of the loops now end up in forms were SE cannot compute loop counts.
However, nevertheless, the test-suite results favor committing:

SingleSource/Benchmarks/BenchmarkGame/puzzle: 26% speedup
MultiSource/Benchmarks/FreeBench/analyzer/analyzer: 21% speedup
MultiSource/Benchmarks/MiBench/automotive-susan/automotive-susan: 20% speedup
SingleSource/Benchmarks/Polybench/linear-algebra/kernels/trisolv/trisolv: 19% speedup
SingleSource/Benchmarks/Polybench/linear-algebra/kernels/gesummv/gesummv: 15% speedup
MultiSource/Benchmarks/FreeBench/pcompress2/pcompress2: 2% speedup

MultiSource/Benchmarks/VersaBench/bmm/bmm: 26% slowdown

llvm-svn: 206120
2014-04-12 21:52:38 +00:00
Rafael Espindola 4f60a38f18 Change how we iterate over relocations on ELF.
For COFF and MachO, sections semantically have relocations that apply to them.
That is not the case on ELF.

In relocatable objects (.o), a section with relocations in ELF has offsets to
another section where the relocations should be applied.

In dynamic objects and executables, relocations don't have an offset, they have
a virtual address. The section sh_info may or may not point to another section,
but that is not actually used for resolving the relocations.

This patch exposes that in the ObjectFile API. It has the following advantages:

* Most (all?) clients can handle this more efficiently. They will normally walk
all relocations, so doing an effort to iterate in a particular order doesn't
save time.

* llvm-readobj now prints relocations in the same way the native readelf does.

* probably most important, relocations that don't point to any section are now
visible. This is the case of relocations in the rela.dyn section. See the
updated relocation-executable.test for example.

llvm-svn: 182908
2013-05-30 03:05:14 +00:00
Nico Rieck ba848e3bca Replace coff-/elf-dump with llvm-readobj
llvm-svn: 179361
2013-04-12 04:06:46 +00:00
Bill Schmidt f5b474c6c6 PPCDAGToDAGISel::PostprocessISelDAG()
This patch implements the PPCDAGToDAGISel::PostprocessISelDAG virtual
method to perform post-selection peephole optimizations on the DAG
representation.

One optimization is implemented here:  folds to clean up complex
addressing expressions for thread-local storage and medium code
model.  It will also be useful for large code model sequences when
those are added later.  I originally thought about doing this on the
MI representation prior to register assignment, but it's difficult to
do effective global dead code elimination at that point.  DCE is
trivial on the DAG representation.

A typical example of a candidate code sequence in assembly:

   addis 3, 2, globalvar@toc@ha
   addi  3, 3, globalvar@toc@l
   lwz   5, 0(3)

When the final instruction is a load or store with an immediate offset
of zero, the offset from the add-immediate can replace the zero,
provided the relocation information is carried along:

   addis 3, 2, globalvar@toc@ha
   lwz   5, globalvar@toc@l(3)

Since the addi can in general have multiple uses, we need to only
delete the instruction when the last use is removed.

llvm-svn: 175697
2013-02-21 00:38:25 +00:00