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Commit Graph

7559 Commits

Author SHA1 Message Date
Thomas Preud'homme
fddc968349 FileCheck [8/12]: Define numeric var from expr
Summary:
This patch is part of a patch series to add support for FileCheck
numeric expressions. This specific patch lift the restriction for a
numeric expression to either be a variable definition or a numeric
expression to try to match.

This commit allows a numeric variable to be set to the result of the
evaluation of a numeric expression after it has been matched
successfully. When it happens, the variable is allowed to be used on
the same line since its value is known at match time.

It also makes use of this possibility to reuse the parsing code to
parse a command-line definition by crafting a mirror string of the
-D option with the equal sign replaced by a colon sign, e.g. for option
'-D#NUMVAL=10' it creates the string
'-D#NUMVAL=10 (parsed as [[#NUMVAL:10]])' where the numeric expression
is parsed to define NUMVAL. This result in a few tests needing updating
for the location diagnostics on top of the tests for the new feature.

It also enables empty numeric expression which match any number without
defining a variable. This is done here rather than in commit #5 of the
patch series because it requires to dissociate automatic regex insertion
in RegExStr from variable definition which would make commit #5 even
bigger than it already is.

Copyright:
    - Linaro (changes up to diff 183612 of revision D55940)
    - GraphCore (changes in later versions of revision D55940 and
                 in new revision created off D55940)

Reviewers: jhenderson, chandlerc, jdenny, probinson, grimar, arichardson, rnk

Subscribers: hiraditya, llvm-commits, probinson, dblaikie, grimar, arichardson, tra, rnk, kristina, hfinkel, rogfer01, JonChesterfield

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D60388

> llvm-svn: 366860

llvm-svn: 366897
2019-07-24 12:38:22 +00:00
Thomas Preud'homme
443542ddca Revert "FileCheck [8/12]: Define numeric var from expr"
This reverts commit 1b05977538d9487aa845ee2f3bec8b89c63c4f29.

llvm-svn: 366872
2019-07-24 07:32:34 +00:00
Thomas Preud'homme
f562841f29 FileCheck [8/12]: Define numeric var from expr
Summary:
This patch is part of a patch series to add support for FileCheck
numeric expressions. This specific patch lift the restriction for a
numeric expression to either be a variable definition or a numeric
expression to try to match.

This commit allows a numeric variable to be set to the result of the
evaluation of a numeric expression after it has been matched
successfully. When it happens, the variable is allowed to be used on
the same line since its value is known at match time.

It also makes use of this possibility to reuse the parsing code to
parse a command-line definition by crafting a mirror string of the
-D option with the equal sign replaced by a colon sign, e.g. for option
'-D#NUMVAL=10' it creates the string
'-D#NUMVAL=10 (parsed as [[#NUMVAL:10]])' where the numeric expression
is parsed to define NUMVAL. This result in a few tests needing updating
for the location diagnostics on top of the tests for the new feature.

It also enables empty numeric expression which match any number without
defining a variable. This is done here rather than in commit #5 of the
patch series because it requires to dissociate automatic regex insertion
in RegExStr from variable definition which would make commit #5 even
bigger than it already is.

Copyright:
    - Linaro (changes up to diff 183612 of revision D55940)
    - GraphCore (changes in later versions of revision D55940 and
                 in new revision created off D55940)

Reviewers: jhenderson, chandlerc, jdenny, probinson, grimar, arichardson, rnk

Subscribers: hiraditya, llvm-commits, probinson, dblaikie, grimar, arichardson, tra, rnk, kristina, hfinkel, rogfer01, JonChesterfield

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D60388

llvm-svn: 366860
2019-07-23 22:41:38 +00:00
Eli Friedman
fd778f3433 [docs] Clarify where the indirect UB due to write-write races comes from
This is based on https://bugs.llvm.org/show_bug.cgi?id=42435#c3.

Patch by Ralf Jung.

llvm-svn: 366855
2019-07-23 21:51:26 +00:00
Francis Visoiu Mistrih
14b03d1c85 [Remarks] Introduce a new format: yaml-strtab
This exposes better support to use a string table with a format through
an actual new remark::Format, called yaml-strtab.

This can now be used with -fsave-optimization-record=yaml-strtab.

llvm-svn: 366849
2019-07-23 20:42:46 +00:00
Ryan Taylor
d817c75cad [IR][Verifier] Allow IntToPtrInst to be !dereferenceable
Summary:
Allow IntToPtrInst to carry !dereferenceable metadata tag.
This is valid since !dereferenceable can be only be applied to
pointer type values.

Change-Id: If8a6e3c616f073d51eaff52ab74535c29ed497b4

Subscribers: llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D64954

llvm-svn: 366826
2019-07-23 17:19:56 +00:00
Chris Lattner
80b9807d04 unbreak links
llvm-svn: 366530
2019-07-19 05:49:11 +00:00
Chris Lattner
d7454a1883 replace the old kaleidoscope tutorial files with orphaned pages that forward to the new copy.
llvm-svn: 366529
2019-07-19 05:23:17 +00:00
Chris Lattner
fd07a98324 Point to the dusted off version of the kaleidoscope tutorial.
llvm-svn: 366528
2019-07-19 05:15:57 +00:00
Jonas Devlieghere
261b5c3196 [CMake] Don't set Python_ADDITIONAL_VERSIONS
Until recently, Python_ADDITIONAL_VERSIONS was used to limit LLVM's
Python support to 2.7. Now that both LLVM and LLDB both support Python
3, there's no longer a need to put an arbitrary limit on this.

However, instead of removing the variable, r365692 expanded the list,
which has the (presumably unintentional) side-effect of expression
preference for Python 3.

Instead, as Michal proposed in the original code review, we should just
not set the list at all, and let CMake pick whatever Python interpreter
you have in your path.

This patch removes the Python_ADDITIONAL_VERSIONS variable in llvm,
clang and lld. I've also updated the docs with the default behavior and
how to force a different Python version to be used.

Differential revision: https://reviews.llvm.org/D64894

llvm-svn: 366447
2019-07-18 15:17:42 +00:00
Hans Wennborg
e94ea4cdc9 Bump the trunk version to 10.0.0svn
and clear the release notes.

llvm-svn: 366427
2019-07-18 11:51:05 +00:00
Nathan Lanza
12f3053d0b Fix typo in programmer's manual cantFile -> cantFail
llvm-svn: 366403
2019-07-18 05:24:22 +00:00
Lang Hames
fa4aa724b9 [ORC][docs] Fix an RST error: the code-block directive needs a newline after it.
llvm-svn: 366270
2019-07-16 21:41:43 +00:00
Lang Hames
50c8118277 [ORC][docs] Trim ORCv1 to ORCv2 transition section, add a how-to section.
llvm-svn: 366269
2019-07-16 21:34:59 +00:00
Alex Brachet
40547610ff Revert [tools] [llvm-nm] Default to reading from stdin not a.out
This reverts r365889 (git commit 60c81354b1d3fced1bd284d334f118d2d792ab4b)

llvm-svn: 366219
2019-07-16 15:33:43 +00:00
Francis Visoiu Mistrih
d9a26939d3 [Remarks] Simplify and refactor the RemarkParser interface
Before, everything was based on some kind of type erased parser
implementation which container a lot of boilerplate code when multiple
formats were to be supported.

This simplifies it by:

* the remark now owns its arguments
* *always* returning an error from the implementation side
* working around the way the YAML parser reports errors: catch them through
callbacks and re-insert them in a proper llvm::Error
* add a CParser wrapper that is used when implementing the C API to
avoid cluttering the C++ API with useless state
* LLVMRemarkParserGetNext now returns an object that needs to be
released to avoid leaking resources
* add a new API to dispose of a remark entry: LLVMRemarkEntryDispose

llvm-svn: 366217
2019-07-16 15:25:05 +00:00
Sylvestre Ledru
5622edf8ed remove a duplicate declaration
llvm-svn: 366205
2019-07-16 12:05:54 +00:00
Sylvestre Ledru
cdbbe489dd Document the LLVM_ENABLE_BINDINGS option
llvm-svn: 366204
2019-07-16 11:59:17 +00:00
Evgeniy Stepanov
e8363137ea ARM MTE stack sanitizer.
Add "memtag" sanitizer that detects and mitigates stack memory issues
using armv8.5 Memory Tagging Extension.

It is similar in principle to HWASan, which is a software implementation
of the same idea, but there are enough differencies to warrant a new
sanitizer type IMHO. It is also expected to have very different
performance properties.

The new sanitizer does not have a runtime library (it may grow one
later, along with a "debugging" mode). Similar to SafeStack and
StackProtector, the instrumentation pass (in a follow up change) will be
inserted in all cases, but will only affect functions marked with the
new sanitize_memtag attribute.

Reviewers: pcc, hctim, vitalybuka, ostannard

Subscribers: srhines, mehdi_amini, javed.absar, kristof.beyls, hiraditya, cryptoad, steven_wu, dexonsmith, cfe-commits, llvm-commits

Tags: #clang, #llvm

Differential Revision: https://reviews.llvm.org/D64169

llvm-svn: 366123
2019-07-15 20:02:23 +00:00
Matt Arsenault
d421a5eebb Add some release notes for 9.0 release
llvm-svn: 366093
2019-07-15 17:50:28 +00:00
James Henderson
9301c3e5a5 [docs][llvm-nm] Fix inconsistent grammar
llvm-svn: 366080
2019-07-15 16:40:34 +00:00
Lang Hames
753edd65d3 [ORC] Start adding ORCv1 to ORCv2 transition tips to the ORCv2 doc.
llvm-svn: 366075
2019-07-15 15:36:37 +00:00
Dmitry Preobrazhensky
25b56899fa [AMDGPU][MC][GFX9][GFX10] Added support of GET_DOORBELL message
Reviewers: artem.tamazov, arsenm

Differential Revision: https://reviews.llvm.org/D64729

llvm-svn: 366071
2019-07-15 15:12:16 +00:00
Richard Sandiford
4b201130c4 DeveloperPolicy: fix a typo
llvm-svn: 366046
2019-07-15 08:09:21 +00:00
Yonghong Song
7ce6119bf4 [BPF] add unit tests for preserve_{array,union,struct}_access_index intrinsics
This is a followup patch for https://reviews.llvm.org/D61810/new/,
which adds new intrinsics preserve_{array,union,struct}_access_index.

Currently, only BPF backend utilizes preserve_{array,union,struct}_access_index
intrinsics, so all tests are compiled with BPF target.

https://reviews.llvm.org/D61524 already added some tests for these
intrinsics, but some of them pretty complex.
This patch added a few unit test cases focusing on individual intrinsic
functions.

Also made a few clarification on language reference for these intrinsics.

Differential Revision: https://reviews.llvm.org/D64606

llvm-svn: 366038
2019-07-15 04:51:34 +00:00
Thomas Preud'homme
04e17bdb7c FileCheck [7/12]: Arbitrary long numeric expressions
Summary:
This patch is part of a patch series to add support for FileCheck
numeric expressions. This specific patch extend numeric expression to
support an arbitrary number of operands, either variable or literals.

Copyright:
    - Linaro (changes up to diff 183612 of revision D55940)
    - GraphCore (changes in later versions of revision D55940 and
                 in new revision created off D55940)

Reviewers: jhenderson, chandlerc, jdenny, probinson, grimar, arichardson, rnk

Subscribers: hiraditya, llvm-commits, probinson, dblaikie, grimar, arichardson, tra, rnk, kristina, hfinkel, rogfer01, JonChesterfield

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D60387

llvm-svn: 366001
2019-07-13 13:24:30 +00:00
Alex Brachet
c32a25d72b [tools] [llvm-nm] Default to reading from stdin not a.out
Summary: This moves away from defaulting to a.out and uses stdin only if stdin has a file redirected to it. This has been discussed on the llvm-dev mailing list [[ https://lists.llvm.org/pipermail/llvm-dev/2019-July/133642.html | here ]].

Reviewers: jhenderson, rupprecht, MaskRay, chrisjackson

Reviewed By: jhenderson, MaskRay

Subscribers: llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D64290

llvm-svn: 365889
2019-07-12 10:20:01 +00:00
Djordje Todorovic
4cf81cc46f Revert "[DwarfDebug] Dump call site debug info"
A build failure was found on the SystemZ platform.

This reverts commit 9e7e73578e54cd22b3c7af4b54274d743b6607cc.

llvm-svn: 365886
2019-07-12 09:45:12 +00:00
Tom Stellard
35fa871df5 docs/GithubMove.rst: Add link to GitHub migration status page
llvm-svn: 365865
2019-07-12 02:31:50 +00:00
Stefan Stipanovic
c892f2c16e [Attributor] Deduce "nosync" function attribute.
Introduce and deduce "nosync" function attribute to indicate that a function
does not synchronize with another thread in a way that other thread might free memory.

Reviewers: jdoerfert, jfb, nhaehnle, arsenm

Subscribers: wdng, hfinkel, nhaenhle, mehdi_amini, steven_wu,
dexonsmith, arsenm, uenoku, hiraditya, jfb, llvm-commits

Differential Revision: https://reviews.llvm.org/D62766

llvm-svn: 365830
2019-07-11 21:37:40 +00:00
Tom Stellard
823dcc0017 docs/GithubMove.rst: Remove obsolete information
Summary:
Remove references to the multirepo and update the document to
reflect the current state of the github repository.

Reviewers: mehdi_amini, jyknight

Subscribers: jdoerfert, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D58420

llvm-svn: 365645
2019-07-10 15:39:37 +00:00
James Henderson
3c12251a2a [docs][llvm-symbolizer] Fix grammar
llvm-svn: 365630
2019-07-10 13:40:45 +00:00
James Henderson
28db65394b [docs][llvm-dwarfdump] Normalise some wording
llvm-svn: 365603
2019-07-10 08:56:13 +00:00
Francis Visoiu Mistrih
e890ba3771 [docs][Remarks] Add documentation for remarks in LLVM
This adds documentation that describes remarks in LLVM.

It aims at explaining what remarks are, how to enable them, and what
users can do with the different modes.

It lists all the available flags in LLVM (excluding clang), and
describes the expected YAML structure as well as the tools that support
the YAML format today.

Differential Revision: https://reviews.llvm.org/D64355

llvm-svn: 365578
2019-07-09 23:16:59 +00:00
Pavel Labath
a47c768731 Add lldb type unit support to the release notes
Reviewers: JDevlieghere, teemperor

Subscribers: llvm-commits, lldb-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D64366

llvm-svn: 365568
2019-07-09 22:36:43 +00:00
Stanislav Mekhanoshin
a7f5d761c5 [AMDGPU] gfx908 target
Differential Revision: https://reviews.llvm.org/D64429

llvm-svn: 365525
2019-07-09 18:10:06 +00:00
James Henderson
2daba67b3d [docs][llvm-dwarfdump] Fix wording
llvm-svn: 365489
2019-07-09 14:20:58 +00:00
James Henderson
1ebc75ef99 [docs][llvm-objdump] Make some wording improvements/simplifications.
llvm-svn: 365474
2019-07-09 12:41:39 +00:00
Djordje Todorovic
0eecf47aa8 [DwarfDebug] Dump call site debug info
Dump the DWARF information about call sites and call site parameters into
debug info sections.

The patch also provides an interface for the interpretation of instructions
that could load values of a call site parameters in order to generate DWARF
about the call site parameters.

([13/13] Introduce the debug entry values.)

Co-authored-by: Ananth Sowda <asowda@cisco.com>
Co-authored-by: Nikola Prica <nikola.prica@rt-rk.com>
Co-authored-by: Ivan Baev <ibaev@cisco.com>

Differential Revision: https://reviews.llvm.org/D60716

llvm-svn: 365467
2019-07-09 11:33:56 +00:00
James Henderson
75c049787d [docs][llvm-nm] Improve some wording
In particular, the --debug-syms switch really doesn't have anything to
do with debuggers, so I've updated the document accordingly.

llvm-svn: 365461
2019-07-09 10:40:50 +00:00
Simon Pilgrim
18c641f2b8 Retire VS2015 Support
As proposed here: https://lists.llvm.org/pipermail/llvm-dev/2019-June/133147.html

This patch raises the minimum supported version to build LLVM/Clang to Visual Studio 2017.

Differential Revision: https://reviews.llvm.org/D64326

llvm-svn: 365452
2019-07-09 10:10:48 +00:00
James Henderson
4e9a0102ed [docs][llvm-dwarfdump] Make some option descriptions clearer and more precise
Some of the wording in the doc (taken largely from the help text), was a
little imprecise in some cases, so this patch makes it a little more
precise.

Reviewed by: JDevlieghere, probinson

Differential Revision: https://reviews.llvm.org/D64332

llvm-svn: 365451
2019-07-09 10:03:12 +00:00
Yonghong Song
61809186ed [BPF] add new intrinsics preserve_{array,union,struct}_access_index
For background of BPF CO-RE project, please refer to
  http://vger.kernel.org/bpfconf2019.html
In summary, BPF CO-RE intends to compile bpf programs
adjustable on struct/union layout change so the same
program can run on multiple kernels with adjustment
before loading based on native kernel structures.

In order to do this, we need keep track of GEP(getelementptr)
instruction base and result debuginfo types, so we
can adjust on the host based on kernel BTF info.
Capturing such information as an IR optimization is hard
as various optimization may have tweaked GEP and also
union is replaced by structure it is impossible to track
fieldindex for union member accesses.

Three intrinsic functions, preserve_{array,union,struct}_access_index,
are introducted.
  addr = preserve_array_access_index(base, index, dimension)
  addr = preserve_union_access_index(base, di_index)
  addr = preserve_struct_access_index(base, gep_index, di_index)
here,
  base: the base pointer for the array/union/struct access.
  index: the last access index for array, the same for IR/DebugInfo layout.
  dimension: the array dimension.
  gep_index: the access index based on IR layout.
  di_index: the access index based on user/debuginfo types.

For example, for the following example,
  $ cat test.c
  struct sk_buff {
     int i;
     int b1:1;
     int b2:2;
     union {
       struct {
         int o1;
         int o2;
       } o;
       struct {
         char flags;
         char dev_id;
       } dev;
       int netid;
     } u[10];
  };

  static int (*bpf_probe_read)(void *dst, int size, const void *unsafe_ptr)
      = (void *) 4;

  #define _(x) (__builtin_preserve_access_index(x))

  int bpf_prog(struct sk_buff *ctx) {
    char dev_id;
    bpf_probe_read(&dev_id, sizeof(char), _(&ctx->u[5].dev.dev_id));
    return dev_id;
  }
  $ clang -target bpf -O2 -g -emit-llvm -S -mllvm -print-before-all \
    test.c >& log

The generated IR looks like below:

  ...
  define dso_local i32 @bpf_prog(%struct.sk_buff*) #0 !dbg !15 {
    %2 = alloca %struct.sk_buff*, align 8
    %3 = alloca i8, align 1
    store %struct.sk_buff* %0, %struct.sk_buff** %2, align 8, !tbaa !45
    call void @llvm.dbg.declare(metadata %struct.sk_buff** %2, metadata !43, metadata !DIExpression()), !dbg !49
    call void @llvm.lifetime.start.p0i8(i64 1, i8* %3) #4, !dbg !50
    call void @llvm.dbg.declare(metadata i8* %3, metadata !44, metadata !DIExpression()), !dbg !51
    %4 = load i32 (i8*, i32, i8*)*, i32 (i8*, i32, i8*)** @bpf_probe_read, align 8, !dbg !52, !tbaa !45
    %5 = load %struct.sk_buff*, %struct.sk_buff** %2, align 8, !dbg !53, !tbaa !45
    %6 = call [10 x %union.anon]* @llvm.preserve.struct.access.index.p0a10s_union.anons.p0s_struct.sk_buffs(
         %struct.sk_buff* %5, i32 2, i32 3), !dbg !53, !llvm.preserve.access.index !19
    %7 = call %union.anon* @llvm.preserve.array.access.index.p0s_union.anons.p0a10s_union.anons(
         [10 x %union.anon]* %6, i32 1, i32 5), !dbg !53
    %8 = call %union.anon* @llvm.preserve.union.access.index.p0s_union.anons.p0s_union.anons(
         %union.anon* %7, i32 1), !dbg !53, !llvm.preserve.access.index !26
    %9 = bitcast %union.anon* %8 to %struct.anon.0*, !dbg !53
    %10 = call i8* @llvm.preserve.struct.access.index.p0i8.p0s_struct.anon.0s(
         %struct.anon.0* %9, i32 1, i32 1), !dbg !53, !llvm.preserve.access.index !34
    %11 = call i32 %4(i8* %3, i32 1, i8* %10), !dbg !52
    %12 = load i8, i8* %3, align 1, !dbg !54, !tbaa !55
    %13 = sext i8 %12 to i32, !dbg !54
    call void @llvm.lifetime.end.p0i8(i64 1, i8* %3) #4, !dbg !56
    ret i32 %13, !dbg !57
  }

  !19 = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "sk_buff", file: !3, line: 1, size: 704, elements: !20)
  !26 = distinct !DICompositeType(tag: DW_TAG_union_type, scope: !19, file: !3, line: 5, size: 64, elements: !27)
  !34 = distinct !DICompositeType(tag: DW_TAG_structure_type, scope: !26, file: !3, line: 10, size: 16, elements: !35)

Note that @llvm.preserve.{struct,union}.access.index calls have metadata llvm.preserve.access.index
attached to instructions to provide struct/union debuginfo type information.

For &ctx->u[5].dev.dev_id,
  . The "%6 = ..." represents struct member "u" with index 2 for IR layout and index 3 for DI layout.
  . The "%7 = ..." represents array subscript "5".
  . The "%8 = ..." represents union member "dev" with index 1 for DI layout.
  . The "%10 = ..." represents struct member "dev_id" with index 1 for both IR and DI layout.

Basically, traversing the use-def chain recursively for the 3rd argument of bpf_probe_read() and
examining all preserve_*_access_index calls, the debuginfo struct/union/array access index
can be achieved.

The intrinsics also contain enough information to regenerate codes for IR layout.
For array and structure intrinsics, the proper GEP can be constructed.
For union intrinsics, replacing all uses of "addr" with "base" should be enough.

The test case ThinLTO/X86/lazyload_metadata.ll is adjusted to reflect the
new addition of the metadata.

Signed-off-by: Yonghong Song <yhs@fb.com>

Differential Revision: https://reviews.llvm.org/D61810

llvm-svn: 365423
2019-07-09 01:51:36 +00:00
Yonghong Song
183feb6712 Revert "[BPF] add new intrinsics preserve_{array,union,struct}_access_index"
This reverts commit r365352.

Test ThinLTO/X86/lazyload_metadata.ll failed. Revert the commit
and at the same time to fix the issue.

llvm-svn: 365360
2019-07-08 17:47:43 +00:00
Dmitry Preobrazhensky
e9cc90bf60 [AMDGPU][MC][DOC] Updated AMD GPU assembler syntax description.
Corrected a typo.

llvm-svn: 365353
2019-07-08 17:09:09 +00:00
Yonghong Song
18796da7b0 [BPF] add new intrinsics preserve_{array,union,struct}_access_index
For background of BPF CO-RE project, please refer to
  http://vger.kernel.org/bpfconf2019.html
In summary, BPF CO-RE intends to compile bpf programs
adjustable on struct/union layout change so the same
program can run on multiple kernels with adjustment
before loading based on native kernel structures.

In order to do this, we need keep track of GEP(getelementptr)
instruction base and result debuginfo types, so we
can adjust on the host based on kernel BTF info.
Capturing such information as an IR optimization is hard
as various optimization may have tweaked GEP and also
union is replaced by structure it is impossible to track
fieldindex for union member accesses.

Three intrinsic functions, preserve_{array,union,struct}_access_index,
are introducted.
  addr = preserve_array_access_index(base, index, dimension)
  addr = preserve_union_access_index(base, di_index)
  addr = preserve_struct_access_index(base, gep_index, di_index)
here,
  base: the base pointer for the array/union/struct access.
  index: the last access index for array, the same for IR/DebugInfo layout.
  dimension: the array dimension.
  gep_index: the access index based on IR layout.
  di_index: the access index based on user/debuginfo types.

For example, for the following example,
  $ cat test.c
  struct sk_buff {
     int i;
     int b1:1;
     int b2:2;
     union {
       struct {
         int o1;
         int o2;
       } o;
       struct {
         char flags;
         char dev_id;
       } dev;
       int netid;
     } u[10];
  };

  static int (*bpf_probe_read)(void *dst, int size, const void *unsafe_ptr)
      = (void *) 4;

  #define _(x) (__builtin_preserve_access_index(x))

  int bpf_prog(struct sk_buff *ctx) {
    char dev_id;
    bpf_probe_read(&dev_id, sizeof(char), _(&ctx->u[5].dev.dev_id));
    return dev_id;
  }
  $ clang -target bpf -O2 -g -emit-llvm -S -mllvm -print-before-all \
    test.c >& log

The generated IR looks like below:

  ...
  define dso_local i32 @bpf_prog(%struct.sk_buff*) #0 !dbg !15 {
    %2 = alloca %struct.sk_buff*, align 8
    %3 = alloca i8, align 1
    store %struct.sk_buff* %0, %struct.sk_buff** %2, align 8, !tbaa !45
    call void @llvm.dbg.declare(metadata %struct.sk_buff** %2, metadata !43, metadata !DIExpression()), !dbg !49
    call void @llvm.lifetime.start.p0i8(i64 1, i8* %3) #4, !dbg !50
    call void @llvm.dbg.declare(metadata i8* %3, metadata !44, metadata !DIExpression()), !dbg !51
    %4 = load i32 (i8*, i32, i8*)*, i32 (i8*, i32, i8*)** @bpf_probe_read, align 8, !dbg !52, !tbaa !45
    %5 = load %struct.sk_buff*, %struct.sk_buff** %2, align 8, !dbg !53, !tbaa !45
    %6 = call [10 x %union.anon]* @llvm.preserve.struct.access.index.p0a10s_union.anons.p0s_struct.sk_buffs(
         %struct.sk_buff* %5, i32 2, i32 3), !dbg !53, !llvm.preserve.access.index !19
    %7 = call %union.anon* @llvm.preserve.array.access.index.p0s_union.anons.p0a10s_union.anons(
         [10 x %union.anon]* %6, i32 1, i32 5), !dbg !53
    %8 = call %union.anon* @llvm.preserve.union.access.index.p0s_union.anons.p0s_union.anons(
         %union.anon* %7, i32 1), !dbg !53, !llvm.preserve.access.index !26
    %9 = bitcast %union.anon* %8 to %struct.anon.0*, !dbg !53
    %10 = call i8* @llvm.preserve.struct.access.index.p0i8.p0s_struct.anon.0s(
         %struct.anon.0* %9, i32 1, i32 1), !dbg !53, !llvm.preserve.access.index !34
    %11 = call i32 %4(i8* %3, i32 1, i8* %10), !dbg !52
    %12 = load i8, i8* %3, align 1, !dbg !54, !tbaa !55
    %13 = sext i8 %12 to i32, !dbg !54
    call void @llvm.lifetime.end.p0i8(i64 1, i8* %3) #4, !dbg !56
    ret i32 %13, !dbg !57
  }

  !19 = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "sk_buff", file: !3, line: 1, size: 704, elements: !20)
  !26 = distinct !DICompositeType(tag: DW_TAG_union_type, scope: !19, file: !3, line: 5, size: 64, elements: !27)
  !34 = distinct !DICompositeType(tag: DW_TAG_structure_type, scope: !26, file: !3, line: 10, size: 16, elements: !35)

Note that @llvm.preserve.{struct,union}.access.index calls have metadata llvm.preserve.access.index
attached to instructions to provide struct/union debuginfo type information.

For &ctx->u[5].dev.dev_id,
  . The "%6 = ..." represents struct member "u" with index 2 for IR layout and index 3 for DI layout.
  . The "%7 = ..." represents array subscript "5".
  . The "%8 = ..." represents union member "dev" with index 1 for DI layout.
  . The "%10 = ..." represents struct member "dev_id" with index 1 for both IR and DI layout.

Basically, traversing the use-def chain recursively for the 3rd argument of bpf_probe_read() and
examining all preserve_*_access_index calls, the debuginfo struct/union/array access index
can be achieved.

The intrinsics also contain enough information to regenerate codes for IR layout.
For array and structure intrinsics, the proper GEP can be constructed.
For union intrinsics, replacing all uses of "addr" with "base" should be enough.

Signed-off-by: Yonghong Song <yhs@fb.com>

Differential Revision: https://reviews.llvm.org/D61810

llvm-svn: 365352
2019-07-08 17:08:28 +00:00
Dmitry Preobrazhensky
d2c3f2c3bb [AMDGPU][MC][DOC] Updated AMD GPU assembler syntax description.
Summary of changes:
- added description of GFX10;
- added description of operands sccz, vccz, lds_direct, etc;
- minor bugfixing and improvements.

llvm-svn: 365347
2019-07-08 16:50:11 +00:00
Brian Homerding
ed0ab9dc76 Add, and infer, a nofree function attribute
This patch adds a function attribute, nofree, to indicate that a function does
not, directly or indirectly, call a memory-deallocation function (e.g., free,
C++'s operator delete).

Reviewers: jdoerfert

Differential Revision: https://reviews.llvm.org/D49165

llvm-svn: 365336
2019-07-08 15:57:56 +00:00
James Henderson
98551a8d55 [docs][llvm-readobj][llvm-readelf] Improve wording
llvm-svn: 365335
2019-07-08 15:46:26 +00:00
Joel E. Denny
cfa953dcab [lit] Parse command-line options from LIT_OPTS
Similar to `FILECHECK_OPTS` for FileCheck, `LIT_OPTS` makes it easy to
adjust lit behavior when running the test suite via ninja.  For
example:

```
$ LIT_OPTS='--time-tests -vv --filter=threadprivate' \
  ninja check-clang-openmp
```

Reviewed By: probinson

Differential Revision: https://reviews.llvm.org/D64135

llvm-svn: 365313
2019-07-08 12:18:40 +00:00