Commit Graph

32323 Commits

Author SHA1 Message Date
Daniel Jasper c0a976d417 Revert r311525: "[XRay][CodeGen] Use PIC-friendly code in XRay sleds; remove synthetic references in .text"
Breaks builds internally. Will forward repo instructions to author.

llvm-svn: 312243
2017-08-31 15:17:17 +00:00
Benjamin Kramer cbc7ee45f9 [Object] Verify object sizes before handing out StringRefs pointing out
of bounds.

This can only happen on corrupt input. Found by OSS-FUZZ!
https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=3228

llvm-svn: 312235
2017-08-31 12:27:10 +00:00
Eric Christopher e42ac21499 Temporarily revert "Update branch coalescing to be a PowerPC specific pass"
From comments and code review it wasn't intended to be enabled by default yet.

This reverts commit r311588.

llvm-svn: 312214
2017-08-31 05:56:16 +00:00
Petr Hosek 5aa80f1663 [yaml2obj][ELF] Make symbols optional for relocations
Some kinds of relocations do not have symbols, like R_X86_64_RELATIVE
for instance. I would like to test this case in D36554 but currently
can't because symbols are required by yaml2obj. The other option is
using the empty symbol but that doesn't seem quite right to me.

This change makes the Symbol field of Relocation optional and in the
case where the user does not specify a symbol name the Symbol index is 0.

Patch by Jake Ehrlich

Differential Revision: https://reviews.llvm.org/D37276

llvm-svn: 312192
2017-08-30 23:13:31 +00:00
Hans Wennborg 24775a0a6c Revert r312154 "Re-enable "[MachineCopyPropagation] Extend pass to do COPY source forwarding""
It caused PR34387: Assertion failed: (RegNo < NumRegs && "Attempting to access record for invalid register number!")

> Issues identified by buildbots addressed since original review:
> - Fixed ARMLoadStoreOptimizer bug exposed by this change in r311907.
> - The pass no longer forwards COPYs to physical register uses, since
>   doing so can break code that implicitly relies on the physical
>   register number of the use.
> - The pass no longer forwards COPYs to undef uses, since doing so
>   can break the machine verifier by creating LiveRanges that don't
>   end on a use (since the undef operand is not considered a use).
>
>   [MachineCopyPropagation] Extend pass to do COPY source forwarding
>
>   This change extends MachineCopyPropagation to do COPY source forwarding.
>
>   This change also extends the MachineCopyPropagation pass to be able to
>   be run during register allocation, after physical registers have been
>   assigned, but before the virtual registers have been re-written, which
>   allows it to remove virtual register COPY LiveIntervals that become dead
>   through the forwarding of all of their uses.

llvm-svn: 312178
2017-08-30 22:11:37 +00:00
Rui Ueyama 01d0265106 Simplify writeArchive return type.
writeArchive returned a pair, but the first element of the pair is always
its first argument on failure, so it doesn't make sense to return it from
the function. This patch change the return type so that it does't return it.

Differential Revision: https://reviews.llvm.org/D37313

llvm-svn: 312177
2017-08-30 22:11:03 +00:00
Adrian Prantl b192b545c1 Refactor DIBuilder::createFragmentExpression into a static DIExpression member
NFC

llvm-svn: 312165
2017-08-30 20:04:17 +00:00
Aditya Nandakumar c6615f56f5 [GISel]: Add a clean up combiner during legalization.
Added a combiner which can clean up truncs/extends that are created in
order to make the types work during legalization.

Also moved the combineMerges to the LegalizeCombiner.

https://reviews.llvm.org/D36880

llvm-svn: 312158
2017-08-30 19:32:59 +00:00
Geoff Berry feffb0c8af Re-enable "[MachineCopyPropagation] Extend pass to do COPY source forwarding"
Issues identified by buildbots addressed since original review:
- Fixed ARMLoadStoreOptimizer bug exposed by this change in r311907.
- The pass no longer forwards COPYs to physical register uses, since
  doing so can break code that implicitly relies on the physical
  register number of the use.
- The pass no longer forwards COPYs to undef uses, since doing so
  can break the machine verifier by creating LiveRanges that don't
  end on a use (since the undef operand is not considered a use).

  [MachineCopyPropagation] Extend pass to do COPY source forwarding

  This change extends MachineCopyPropagation to do COPY source forwarding.

  This change also extends the MachineCopyPropagation pass to be able to
  be run during register allocation, after physical registers have been
  assigned, but before the virtual registers have been re-written, which
  allows it to remove virtual register COPY LiveIntervals that become dead
  through the forwarding of all of their uses.

llvm-svn: 312154
2017-08-30 18:41:07 +00:00
Adrian Prantl 05782218ab Canonicalize the representation of empty an expression in DIGlobalVariableExpression
This change simplifies code that has to deal with
DIGlobalVariableExpression and mirrors how we treat DIExpressions in
debug info intrinsics. Before this change there were two ways of
representing empty expressions on globals, a nullptr and an empty
!DIExpression().

If someone needs to upgrade out-of-tree testcases:
  perl -pi -e 's/(!DIGlobalVariableExpression\(var: ![0-9]*)\)/\1, expr: !DIExpression())/g' <MYTEST.ll>
will catch 95%.

llvm-svn: 312144
2017-08-30 18:06:51 +00:00
Craig Topper baae732946 [X86] Remove GCCBuiltin for some intrinsics that aren't used by clang. Add TODO to remove them.
llvm-svn: 312136
2017-08-30 16:28:09 +00:00
Lang Hames 3025e48a88 [Error] Add an optional error message to cantFail.
cantFail is the moral equivalent of an assertion that the wrapped call must
return a success value. This patch allows clients to include an associated
error message (the same way they would for an assertion for llvm_unreachable).

If the error message is not specified it will default to: "Failure value
returned from cantFail wrapped call".

llvm-svn: 312066
2017-08-29 23:29:09 +00:00
Reid Kleckner 0452052395 Fix indentation of find_first_existing_vc_file
llvm-svn: 312044
2017-08-29 21:44:46 +00:00
Reid Kleckner b8ae2b132a [cmake] Stop putting the revision info in LLVM_VERSION_STRING
Summary:
This reduces the number of build actions after a no-op commit from
thousands to about six, which should be acceptable. If six actions is
still too many, developers can disable the LLVM_APPEND_VC_REV cmake
option.

llvm-config.h is a widely included header that should rarely change.
Before this patch, it would change after every re-configure. Very few
users of llvm-config.h need to know the precise version, and those that
do can migrate to incorporating LLVM_REVISION as provided by
llvm/Support/VCSRevision.h.

This should bring LLVM back to the behavior that it had before r306858
from June 30 2017. Most LLVM tools will now print a version string like
"6.0.0svn" instead of "6.0.0-git-c40c2a23de4".

Fixes PR34308

Reviewers: pcc, rafael, hans

Subscribers: mgorny, llvm-commits

Differential Revision: https://reviews.llvm.org/D37272

llvm-svn: 312043
2017-08-29 21:44:21 +00:00
Reid Kleckner a058736c9c [dwarfdump] Pretty print location expressions and location lists
Summary:
Based on Fred's patch here: https://reviews.llvm.org/D6771

I can't seem to commandeer the old review, so I'm creating a new one.

With that change the locations exrpessions are pretty printed inline in the
DIE tree. The output looks like this for debug_loc entries:

    DW_AT_location [DW_FORM_data4]        (0x00000000
       0x0000000000000001 - 0x000000000000000b: DW_OP_consts +3
       0x000000000000000b - 0x0000000000000012: DW_OP_consts +7
       0x0000000000000012 - 0x000000000000001b: DW_OP_reg0 RAX, DW_OP_piece 0x4
       0x000000000000001b - 0x0000000000000024: DW_OP_breg5 RDI+0)

And like this for debug_loc.dwo entries:
    DW_AT_location [DW_FORM_sec_offset]   (0x00000000
      Addr idx 2 (w/ length 190): DW_OP_consts +0, DW_OP_stack_value
      Addr idx 3 (w/ length 23): DW_OP_reg0 RAX, DW_OP_piece 0x4)

Simple locations without ranges are printed inline:

   DW_AT_location [DW_FORM_block1]       (DW_OP_reg4 RSI, DW_OP_piece 0x4, DW_OP_bit_piece 0x20 0x0)

The debug_loc(.dwo) dumping in changed accordingly to factor the code.

Reviewers: dblaikie, aprantl, friss

Subscribers: mgorny, javed.absar, hiraditya, llvm-commits, JDevlieghere

Differential Revision: https://reviews.llvm.org/D37123

llvm-svn: 312042
2017-08-29 21:41:21 +00:00
Hans Wennborg e7becd7e85 [DAG] Bound loop dependence check in merge optimization.
The loop dependence check looks for dependencies between store merge
candidates not captured by the chain sub-DAG doing a check of
predecessors which may be very large. Conservatively bound number of
nodes checked for compilation time. (Resolves PR34326).

Landing on behalf of Nirav Dave to unblock the 5.0.0 release.

Differential Revision: https://reviews.llvm.org/D37220

llvm-svn: 312022
2017-08-29 18:41:00 +00:00
Sanjay Patel 674d2c23ea [Instruction] add moveAfter() convenience function; NFCI
As suggested in D37121, here's a wrapper for removeFromParent() + insertAfter(),
but implemented using moveBefore() for symmetry/efficiency.

Differential Revision: https://reviews.llvm.org/D37239

llvm-svn: 312001
2017-08-29 14:07:48 +00:00
Yuka Takahashi 24bc6a4c4f Revert "Revert r311552: [Bash-autocompletion] Add support for static analyzer flags"
This reverts commit 7c46b80c022e18d43c1fdafb117b0c409c5a6d1e.

r311552 broke lld buildbot because I've changed OptionInfos type from
ArrayRef to vector. However the bug is fixed, so I'll commit this again.

llvm-svn: 311958
2017-08-29 00:09:31 +00:00
Zachary Turner a7b041748d [CodeView] Don't output S_UDT symbols for forward decls.
S_UDT symbols are the debugger's "index" for all the structs,
typedefs, classes, and enums in a program.  If any of those
structs/classes don't have a complete declaration, or if there
is a typedef to something that doesn't have a complete definition,
then emitting the S_UDT is unhelpful because it doesn't give
the debugger enough information to do anything useful.  On the
other hand, it results in a huge size blow-up in the resulting
PDB, which is exacerbated by an order of magnitude when linking
with /DEBUG:FASTLINK.

With this patch, we drop S_UDT records for types that refer either
directly or indirectly (e.g. through a typedef, pointer, etc) to
a class/struct/union/enum without a complete definition.  This
brings us about 50% of the way towards parity with /DEBUG:FASTLINK
PDBs generated from cl-compiled object files.

Differential Revision: https://reviews.llvm.org/D37162

llvm-svn: 311904
2017-08-28 18:49:04 +00:00
Evgeny Mankov 1587086f88 [Support][CommandLine] Add cl::Option::setDefault()
Add abstract virtual method setDefault() to class Option and implement it in its inheritors in order to be able to set all the options to its default values in user's code without actually knowing all these options. For instance:

for (auto &OM : cl::getRegisteredOptions(*cl::TopLevelSubCommand)) {
  cl::Option *O = OM.second;
  O->setDefault();
}

Reviewed by: rampitec, Eugene.Zelenko, kasaurov

Differential Revision: http://reviews.llvm.org/D36877

llvm-svn: 311887
2017-08-28 13:39:43 +00:00
NAKAMURA Takumi ac08375ad5 Prune whitespaces in blank lines.
llvm-svn: 311876
2017-08-28 07:48:37 +00:00
NAKAMURA Takumi a1e97a77f5 Untabify.
llvm-svn: 311875
2017-08-28 06:47:47 +00:00
Lang Hames 5d06c23d4c [Error] Add a handleExpected utility.
handleExpected is similar to handleErrors, but takes an Expected<T> as its first
input value and a fallback functor as its second, followed by an arbitary list
of error handlers (equivalent to the handler list of handleErrors). If the first
input value is a success value then it is returned from handleErrors
unmodified. Otherwise the contained error(s) are passed to handleErrors, along
with the handlers. If handleErrors returns success (indicating that all errors
have been handled) then handleExpected runs the fallback functor and returns its
result. If handleErrors returns a failure value then the failure value is
returned and the fallback functor is never run.

This simplifies the process of re-trying operations that return Expected values.
Without this utility such retry logic is cumbersome as the internal Error must
be explicitly extracted from the Expected value, inspected to see if its
handleable and then consumed:

enum FooStrategy { Aggressive, Conservative };
Expected<Foo> tryFoo(FooStrategy S);

Expected<Foo> Result;
(void)!!Result; // "Check" Result so that it can be safely overwritten.
if (auto ValOrErr = tryFoo(Aggressive))
  Result = std::move(ValOrErr);
else {
  auto Err = ValOrErr.takeError();
  if (Err.isA<HandleableError>()) {
    consumeError(std::move(Err));
    Result = tryFoo(Conservative);
  } else
    return std::move(Err);
}

with handleExpected, this can be re-written as:

auto Result =
  handleExpected(
    tryFoo(Aggressive),
    []() { return tryFoo(Conservative); },
    [](HandleableError&) { /* discard to handle */ });

llvm-svn: 311870
2017-08-28 03:36:46 +00:00
Aditya Nandakumar 892979effc [GISel]: Implement widenScalar for Legalizing G_PHI
https://reviews.llvm.org/D37018

llvm-svn: 311763
2017-08-25 04:57:27 +00:00
Matt Arsenault f5fb1e8bca DAG: Fix naming crime
Because isOperationCustom was only checking for custom
lowering on illegal types, this was behaving inconsistently
with the other isOperation* functions, so that
isOperationLegalOrCustom != (isOperationLegal || isOperationCustom)

Luckily this is only used in one place which already checks the
type legality on its own.

llvm-svn: 311743
2017-08-25 01:26:13 +00:00
Stephen Hines cc14a386d8 Fix two (three) more issues with unchecked Error.
Summary:
If assertions are disabled, but LLVM_ABI_BREAKING_CHANGES is enabled,
this will cause an issue with an unchecked Success. Switching to
consumeError() is the correct way to bypass the check. This patch also
includes disabling 2 tests that can't work without assertions enabled,
since llvm_unreachable() with NDEBUG won't crash.

Reviewers: llvm-commits, lhames

Reviewed By: lhames

Subscribers: lhames, pirama

Differential Revision: https://reviews.llvm.org/D36729

llvm-svn: 311739
2017-08-25 00:48:21 +00:00
Sanjay Patel e404cbff66 [DAG] convert vector select-of-constants to logic/math
This goes back to a discussion about IR canonicalization. We'd like to preserve and convert
more IR to 'select' than we currently do because that's likely the best choice in IR:
http://lists.llvm.org/pipermail/llvm-dev/2016-September/105335.html
...but that's often not true for codegen, so we need to account for this pattern coming in
to the backend and transform it to better DAG ops.

Steps in this patch:

  1. Add an EVT param to the existing convertSelectOfConstantsToMath() TLI hook to more finely
     enable this transform. Other targets will probably want that anyway to distinguish scalars
     from vectors. We're using that here to exclude AVX512 targets, but it may not be necessary.

  2. Convert a vselect to ext+add. This eliminates a constant load/materialization, and the
     vector ext is often free.

Implementing a more general fold using xor+and can be a follow-up for targets that don't have
a legal vselect. It's also possible that we can remove the TLI hook for the special case fold
implemented here because we're eliminating a constant, but it needs to be tested on other
targets.

Differential Revision: https://reviews.llvm.org/D36840

llvm-svn: 311731
2017-08-24 23:24:43 +00:00
Mandeep Singh Grang 872f689d0a [ADT] Enable reverse iteration for DenseMap
Reviewers: mehdi_amini, dexonsmith, dblaikie, davide, chandlerc, davidxl, echristo, efriedma

Reviewed By: dblaikie

Subscribers: rsmith, mgorny, emaste, llvm-commits

Differential Revision: https://reviews.llvm.org/D35043

llvm-svn: 311730
2017-08-24 23:02:48 +00:00
Dehao Chen f0e27e63e7 Move accurate-sample-profile into the function attribute.
Summary: We need to have accurate-sample-profile in function attribute so that it works with LTO.

Reviewers: davidxl, rsmith

Reviewed By: davidxl

Subscribers: sanjoy, mehdi_amini, javed.absar, llvm-commits, eraman

Differential Revision: https://reviews.llvm.org/D37113

llvm-svn: 311706
2017-08-24 21:37:04 +00:00
Pete Couperus 2d1f6d67c5 [ARC] Add ARC backend.
Add the ARC backend as an experimental target to lib/Target.
Reviewed at: https://reviews.llvm.org/D36331

llvm-svn: 311667
2017-08-24 15:40:33 +00:00
Krasimir Georgiev 719f97cf65 [X86AsmParser] Refactor AsmRewrite constructors, NFCI
Summary:
This is a follow-up of https://reviews.llvm.org/D37105, where a slight refactoring
of the constructors of AsmRewrite is proposed.

Reviewers: coby

Reviewed By: coby

Differential Revision: https://reviews.llvm.org/D37110

llvm-svn: 311666
2017-08-24 15:03:18 +00:00
Sanjay Patel 1cc58ecc8a fix typo; NFC
llvm-svn: 311665
2017-08-24 15:00:13 +00:00
Sanjay Patel 5d67d8916e [BypassSlowDivision] move map helper code to header; NFC
We can reuse this code with other div/rem transforms as shown in:
https://reviews.llvm.org/D31037 
https://bugs.llvm.org/show_bug.cgi?id=31028

llvm-svn: 311661
2017-08-24 14:43:33 +00:00
Chad Rosier bfd4014304 [TargetParser][AArch64] Add support for RDM feature in the target parser.
Differential Revision: https://reviews.llvm.org/D37081

llvm-svn: 311659
2017-08-24 14:30:44 +00:00
Krasimir Georgiev 9ee966548e [X86AsmParser] Fix msan: use-of-uninitialized-value after r311639
Summary:
CodeGen/ms-inline-asm.c test triggers msan use-of-uninitialized-value here:
llvm/lib/MC/MCParser/AsmParser.cpp:5629:7

Reviewers: bkramer, coby

Differential Revision: https://reviews.llvm.org/D37105

llvm-svn: 311653
2017-08-24 13:38:18 +00:00
Tobias Grosser d7eb619299 Model cache size and associativity in TargetTransformInfo
Summary:
We add the precise cache sizes and associativity for the following Intel
architectures:

  - Penry
  - Nehalem
  - Westmere
  - Sandy Bridge
  - Ivy Bridge
  - Haswell
  - Broadwell
  - Skylake
  - Kabylake

Polly uses since several months a performance model for BLAS computations that
derives optimal cache and register tile sizes from cache and latency
information (based on ideas from "Analytical Modeling Is Enough for High-Performance BLIS", by Tze Meng Low published at TOMS 2016).
While bootstrapping this model, these target values have been kept in Polly.
However, as our implementation is now rather mature, it seems time to teach
LLVM itself about cache sizes.

Interestingly, L1 and L2 cache sizes are pretty constant across
micro-architectures, hence a set of architecture specific default values
seems like a good start. They can be expanded to more target specific values,
in case certain newer architectures require different values. For now a set
of Intel architectures are provided.

Just as a little teaser, for a simple gemm kernel this model allows us to
improve performance from 1.2s to 0.27s. For gemm kernels with less optimal
memory layouts even larger speedups can be reported.

Reviewers: Meinersbur, bollu, singam-sanjay, hfinkel, gareevroman, fhahn, sebpop, efriedma, asb

Reviewed By: fhahn, asb

Subscribers: lsaba, asb, pollydev, llvm-commits

Differential Revision: https://reviews.llvm.org/D37051

llvm-svn: 311647
2017-08-24 09:46:25 +00:00
Daniel Sanders 2c269f6bf8 Re-commit: [globalisel][tablegen] Add support for ImmLeaf without SDNodeXForm
Summary:
This patch adds support for predicates on imm nodes but only for ImmLeaf and not
for PatLeaf or PatFrag and only where the value does not need to be transformed
before being rendered into the instruction.

The limitation on PatLeaf/PatFrag/SDNodeXForm is due to differences in the
necessary target-supplied C++ for GlobalISel.

Depends on D36085

The previous commit was reverted for breaking the build but this appears to have
been the recurring problem on the Windows bots with tablegen not being re-run
when llvm-tblgen is changed but the .td's aren't. If it re-occurs then forcing a
build with clean=True should fix it but this string should do this in advance:
    Requires a clean build.

Reviewers: ab, t.p.northover, qcolombet, rovka, aditya_nandakumar

Reviewed By: rovka

Subscribers: kristof.beyls, javed.absar, igorb, llvm-commits

Differential Revision: https://reviews.llvm.org/D36086

llvm-svn: 311645
2017-08-24 09:11:20 +00:00
Coby Tayree d89128925b [X86AsmParser] Refactoring, (almost) NFC.
Some refactoring to X86AsmParser, mostly regarding the way rewrites are conducted.
Mainly, we try to concentrate all the rewrite effort under one hood, so it'll hopefully be less of a mess and easier to maintain and understand.
naturally, some frontend tests were affected: D36794

Differential Revision: https://reviews.llvm.org/D36793

llvm-svn: 311639
2017-08-24 08:46:25 +00:00
Lang Hames 7febf2baff [Support] Rewrite handleAllErrors in terms of cantFail.
This just switches handleAllErrors from using custom assertions that all errors
have been handled to using cantFail. This change involves moving some of the
class and function definitions around though.

llvm-svn: 311631
2017-08-24 05:35:27 +00:00
Wei Ding a131d3fb29 Add ‘llvm.experimental.constrained.fma‘ Intrinsic.
Differential Revision: http://reviews.llvm.org/D36335

llvm-svn: 311629
2017-08-24 04:18:24 +00:00
Adam Nemet 0ada0d5b21 Support all integer types in DiagnosticInfoOptimizationBase::Argument
We were missing size_t (unsigned long) on macOS.

llvm-svn: 311628
2017-08-24 04:04:49 +00:00
Eric Beckmann b85172f6ff Fix bug 34051 by handling empty .res files gracefully.
Summary:
Previously, llvm-cvtres crashes on .res files which are empty except for
the null header.  This allows the library to simply pass over them.

Subscribers: llvm-commits, hiraditya

Differential Revision: https://reviews.llvm.org/D37044

llvm-svn: 311625
2017-08-24 02:36:50 +00:00
Aditya Nandakumar efd8a84cd5 [GISEl]: Translate phi into G_PHI
G_PHI has the same semantics as PHI but also has types.
This lets us verify that the types in the G_PHI are consistent.
This also allows specifying legalization actions for G_PHIs.

https://reviews.llvm.org/D36990

llvm-svn: 311596
2017-08-23 20:45:48 +00:00
Lei Huang 0cb591fc4c Update branch coalescing to be a PowerPC specific pass
Implementing this pass as a PowerPC specific pass.  Branch coalescing utilizes
the analyzeBranch method which currently does not include any implicit operands.
This is not an issue on PPC but must be handled on other targets.

Differential Revision : https: // reviews.llvm.org/D32776

llvm-svn: 311588
2017-08-23 19:25:04 +00:00
Victor Leschuk 3697ebe25f Revert r311546 as it breaks build
http://lab.llvm.org:8011/builders/llvm-clang-x86_64-expensive-checks-win/builds/4394

llvm-svn: 311560
2017-08-23 15:21:10 +00:00
Rui Ueyama a93f087d3e Revert r311552: [Bash-autocompletion] Add support for static analyzer flags
This reverts commit r311552 because it broke ubsan and asan bots.

llvm-svn: 311557
2017-08-23 14:48:58 +00:00
Yuka Takahashi 5e7071f5d7 [Bash-autocompletion] Add support for static analyzer flags
Summary:
This is a patch for clang autocomplete feature.

It will collect values which -analyzer-checker takes, which is defined in
clang/StaticAnalyzer/Checkers/Checkers.inc, dynamically.
First, from ValuesCode class in Options.td, TableGen will generate C++
code in Options.inc. Options.inc will be included in DriverOptions.cpp, and
calls OptTable's addValues function. addValues function will add second
argument to Option's Values class. Values contains string like "foo,bar,.."
which is handed to Values class
in OptTable.

Reviewers: v.g.vassilev, teemperor, ruiu

Subscribers: hiraditya, cfe-commits

Differential Revision: https://reviews.llvm.org/D36782

llvm-svn: 311552
2017-08-23 13:39:47 +00:00
Daniel Sanders c3885c4589 [globalisel][tablegen] Add support for ImmLeaf without SDNodeXForm
Summary:
This patch adds support for predicates on imm nodes but only for ImmLeaf and not for PatLeaf or PatFrag and only where the value does not need to be transformed before being rendered into the instruction.

The limitation on PatLeaf/PatFrag/SDNodeXForm is due to differences in the necessary target-supplied C++ for GlobalISel.

Depends on D36085

Reviewers: ab, t.p.northover, qcolombet, rovka, aditya_nandakumar

Reviewed By: rovka

Subscribers: kristof.beyls, javed.absar, igorb, llvm-commits

Differential Revision: https://reviews.llvm.org/D36086

llvm-svn: 311546
2017-08-23 12:14:18 +00:00
Dean Michael Berris 0884b73220 [XRay][CodeGen] Use PIC-friendly code in XRay sleds; remove synthetic references in .text
Summary:
This change achieves two things:

  - Redefine the Custom Event handling instrumentation points emitted by
    the compiler to not require dynamic relocation of references to the
    __xray_CustomEvent trampoline.

  - Remove the synthetic reference we emit at the end of a function that
    we used to keep auxiliary sections alive in favour of SHF_LINK_ORDER
    associated with the section where the function is defined.

To achieve the custom event handling change, we've had to introduce the
concept of sled versioning -- this will need to be supported by the
runtime to allow us to understand how to turn on/off the new version of
the custom event handling sleds. That change has to land first before we
change the way we write the sleds.

To remove the synthetic reference, we rely on a relatively new linker
feature that preserves the sections that are associated with each other.
This allows us to limit the effects on the .text section of ELF
binaries.

Because we're still using absolute references that are resolved at
runtime for the instrumentation map (and function index) maps, we mark
these sections write-able. In the future we can re-define the entries in
the map to use relative relocations instead that can be statically
determined by the linker. That change will be a bit more invasive so we
defer this for later.

Depends on D36816.

Reviewers: dblaikie, echristo, pcc

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D36615

llvm-svn: 311525
2017-08-23 04:49:41 +00:00
Yonghong Song dc1dbf6ef3 bpf: add variants of -mcpu=# and support for additional jmp insns
-mcpu=# will support:
  . generic: the default insn set
  . v1: insn set version 1, the same as generic
  . v2: insn set version 2, version 1 + additional jmp insns
  . probe: the compiler will probe the underlying kernel to
           decide proper version of insn set.

We did not not use -mcpu=native since llc/llvm will interpret -mcpu=native
as the underlying hardware architecture regardless of -march value.

Currently, only x86_64 supports -mcpu=probe. Other architecture will
silently revert to "generic".

Also added -mcpu=help to print available cpu parameters.
llvm will print out the information only if there are at least one
cpu and at least one feature. Add an unused dummy feature to
enable the printout.

Examples for usage:
$ llc -march=bpf -mcpu=v1 -filetype=asm t.ll
$ llc -march=bpf -mcpu=v2 -filetype=asm t.ll
$ llc -march=bpf -mcpu=generic -filetype=asm t.ll
$ llc -march=bpf -mcpu=probe -filetype=asm t.ll
$ llc -march=bpf -mcpu=v3 -filetype=asm t.ll
'v3' is not a recognized processor for this target (ignoring processor)
...
$ llc -march=bpf -mcpu=help -filetype=asm t.ll
Available CPUs for this target:

  generic - Select the generic processor.
  probe   - Select the probe processor.
  v1      - Select the v1 processor.
  v2      - Select the v2 processor.

Available features for this target:

  dummy - unused feature.

Use +feature to enable a feature, or -feature to disable it.
For example, llc -mcpu=mycpu -mattr=+feature1,-feature2
...

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Yonghong Song <yhs@fb.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
llvm-svn: 311522
2017-08-23 04:25:57 +00:00