Commit Graph

553 Commits

Author SHA1 Message Date
Arthur Eubanks afff74e5c2 [HWAsan][NewPM] Handle hwasan like other sanitizers
Move it as an EP callback (-O[123]) or in addSanitizersAtO0.

This makes it not run in ThinLTO pre-link (like the other sanitizers),
so don't check LTO runs in hwasan-new-pm.c. Changing its position also
seems to change the generated IR. I think we just need to make sure the
pass runs.

Reviewed By: leonardchan

Differential Revision: https://reviews.llvm.org/D88936
2020-10-08 14:43:21 -07:00
diggerlin 92bca12843 [AIX] add new option -mignore-xcoff-visibility
SUMMARY:

In IBM compiler xlclang , there is an option -fnovisibility which suppresses visibility. For more details see: https://www.ibm.com/support/knowledgecenter/SSGH3R_16.1.0/com.ibm.xlcpp161.aix.doc/compiler_ref/opt_visibility.html.

We need to add the option -mignore-xcoff-visibility for compatibility with the IBM AIX OS (as the option is enabled by default in AIX). With this option llvm does not emit any visibility attribute to ASM or XCOFF object file.

The option only work on the AIX OS, for other non-AIX OS using the option will report an unsupported options error.

In AIX OS:

1.1  the option -mignore-xcoff-visibility is enabled by default , if there is not -fvisibility=* and -mignore-xcoff-visibility explicitly in the clang command .

1.2 if there is -fvisibility=* explicitly but not -mignore-xcoff-visibility  explicitly in the clang command.  it will generate visibility attributes.

1.3 if there are  both  -fvisibility=* and  -mignore-xcoff-visibility  explicitly in the clang command. The option  "-mignore-xcoff-visibility" wins , it do not emit the visibility attribute.

The option -mignore-xcoff-visibility has no effect on visibility attribute when compile with -emit-llvm option to generated LLVM IR.

Reviewer: daltenty,Jason Liu

Differential Revision: https://reviews.llvm.org/D87451
2020-10-08 09:34:58 -04:00
Arthur Eubanks ce5379f0f0 [NPM] Add target specific hook to add passes for New Pass Manager
The patch adds a new TargetMachine member "registerPassBuilderCallbacks" for targets to add passes to the pass pipeline using the New Pass Manager (similar to adjustPassManager for the Legacy Pass Manager).

Reviewed By: aeubanks

Differential Revision: https://reviews.llvm.org/D88138
2020-09-30 13:29:43 -07:00
Fangrui Song 3681be876f Add -fprofile-update={atomic,prefer-atomic,single}
GCC 7 introduced -fprofile-update={atomic,prefer-atomic} (prefer-atomic is for
best efforts (some targets do not support atomics)) to increment counters
atomically, which is exactly what we have done with -fprofile-instr-generate
(D50867) and -fprofile-arcs (b5ef137c11).
This patch adds the option to clang to surface the internal options at driver level.

GCC 7 also turned on -fprofile-update=prefer-atomic when -pthread is specified,
but it has performance regression
(https://gcc.gnu.org/bugzilla/show_bug.cgi?id=89307). So we don't follow suit.

Differential Revision: https://reviews.llvm.org/D87737
2020-09-29 10:43:23 -07:00
Sriraman Tallam 7d0bbe4090 Re-apply https://reviews.llvm.org/D87921, was reverted to triage a PPC bot failure.
D87921 was reverted in commit b89059a313
as it was causing an unknown llvm PPC bot failure.  Reapplying the patch
after confirming that this is not responsible. Build bot failure:
https://reviews.llvm.org/D87921#2286644  which caused the revert.

The wrong placement of add pass with optimizations led to
-funique-internal-linkage-names being disabled.

Fixed the placement of the MPM.addpass for UniqueInternalLinkageNames to make it
work correctly with -O2 and new pass manager. Updated the tests to explicitly
check O0 and O1.

Differential Revision: https://reviews.llvm.org/D87921
2020-09-23 10:28:40 -07:00
Mircea Trofin cf112382dd [ThinLTO] Option to bypass function importing.
This completes the circle, complementing -lto-embed-bitcode
(specifically, post-merge-pre-opt). Using -thinlto-assume-merged skips
function importing. The index file is still needed for the other data it
contains.

Differential Revision: https://reviews.llvm.org/D87949
2020-09-22 13:12:11 -07:00
Sriraman Tallam b89059a313 Revert "The wrong placement of add pass with optimizations led to -funique-internal-linkage-names being disabled."
This reverts commit 6950db36d3.
2020-09-22 12:32:43 -07:00
Sriraman Tallam 6950db36d3 The wrong placement of add pass with optimizations led to -funique-internal-linkage-names being disabled.
Fixed the placement of the MPM.addpass for UniqueInternalLinkageNames to make
it work correctly with -O2 and new pass manager. Updated the tests to
explicitly check O0 and O2.

Previously, the addPass was placed before BackendUtil.cpp#L1373 which is wrong
as MPM gets assigned at this point and any additions to the pass vector before
this is wrong. This change just moves it after MPM is assigned and places it at
a point where O0 and O0+ can share it.

Differential Revision: https://reviews.llvm.org/D87921
2020-09-21 10:00:12 -07:00
Mircea Trofin 61fc10d6a5 [ThinLTO] add post-thinlto-merge option to -lto-embed-bitcode
This will embed bitcode after (Thin)LTO merge, but before optimizations.
In the case the thinlto backend is called from clang, the .llvmcmd
section is also produced. Doing so in the case where the caller is the
linker doesn't yet have a motivation, and would require plumbing through
command line args.

Differential Revision: https://reviews.llvm.org/D87636
2020-09-15 15:56:11 -07:00
Snehasish Kumar f1a3ab9044 [clang] Add a command line flag for the Machine Function Splitter.
This patch adds a command line flag for the machine function splitter
(added in rG94faadaca4e1).

-fsplit-machine-functions
Split machine functions using profile information (x86 ELF). On
other targets an error is emitted. If profile information is not
provided a warning is emitted notifying the user that profile
information is required.

Differential Revision: https://reviews.llvm.org/D87047
2020-09-15 12:41:58 -07:00
Teresa Johnson 226d80ebe2 [MemProf] Rename HeapProfiler to MemProfiler for consistency
This is consistent with the clang option added in
7ed8124d46, and the comments on the
runtime patch in D87120.

Differential Revision: https://reviews.llvm.org/D87622
2020-09-14 13:14:57 -07:00
Fangrui Song b5ef137c11 [gcov] Increment counters with atomicrmw if -fsanitize=thread
Without this patch, `clang --coverage -fsanitize=thread` may fail spuriously
because non-atomic counter increments can be detected as data races.
2020-08-28 16:32:35 -07:00
Teresa Johnson 7ed8124d46 [HeapProf] Clang and LLVM support for heap profiling instrumentation
See RFC for background:
http://lists.llvm.org/pipermail/llvm-dev/2020-June/142744.html

Note that the runtime changes will be sent separately (hopefully this
week, need to add some tests).

This patch includes the LLVM pass to instrument memory accesses with
either inline sequences to increment the access count in the shadow
location, or alternatively to call into the runtime. It also changes
calls to memset/memcpy/memmove to the equivalent runtime version.
The pass is modeled on the address sanitizer pass.

The clang changes add the driver option to invoke the new pass, and to
link with the upcoming heap profiling runtime libraries.

Currently there is no attempt to optimize the instrumentation, e.g. to
aggregate updates to the same memory allocation. That will be
implemented as follow on work.

Differential Revision: https://reviews.llvm.org/D85948
2020-08-27 08:50:35 -07:00
Jeremy Morse 121a49d839 [LiveDebugValues] Add switches for using instr-ref variable locations
This patch adds the -Xclang option
"-fexperimental-debug-variable-locations" and same LLVM CodeGen option,
to pick which variable location tracking solution to use.

Right now all the switch does is pick which LiveDebugValues
implementation to use, the normal VarLoc one or the instruction
referencing one in rGae6f78824031. Over time, the aim is to add fragments
of support in aid of the value-tracking RFC:

  http://lists.llvm.org/pipermail/llvm-dev/2020-February/139440.html

also controlled by this command line switch. That will slowly move
variable locations to be defined by an instruction calculating a value,
and a DBG_INSTR_REF instruction referring to that value. Thus, this is
going to grow into a "use the new kind of variable locations" switch,
rather than just "use the new LiveDebugValues implementation".

Differential Revision: https://reviews.llvm.org/D83048
2020-08-25 14:58:48 +01:00
Kai Nacke b3aece0531 [SystemZ/ZOS] Add binary format goff and operating system zos to the triple
Adds the binary format goff and the operating system zos to the triple
class. goff is selected as default binary format if zos is choosen as
operating system. No further functionality is added.

Reviewers: efriedma, tahonermann, hubert.reinterpertcast, MaskRay

Reviewed By: efriedma, tahonermann, hubert.reinterpertcast

Differential Revision: https://reviews.llvm.org/D82081
2020-08-11 05:26:26 -04:00
Arthur Eubanks 71d0a2b8a3 [DFSan][NewPM] Port DataFlowSanitizer to NewPM
Reviewed By: ychen, morehouse

Differential Revision: https://reviews.llvm.org/D84707
2020-07-29 10:19:15 -07:00
Sjoerd Meijer 5567c62afa [Matrix] Add LowerMatrixIntrinsics to the NPM
Pass LowerMatrixIntrinsics wasn't running yet running under the new pass
manager, and this adds LowerMatrixIntrinsics to the pipeline (to the
same place as where it is running in the old PM).

Differential Revision: https://reviews.llvm.org/D84180
2020-07-22 09:47:53 +01:00
Arthur Eubanks b13b858182 [NewPM] Support optnone under new pass manager
OptNoneInstrumentation is part of StandardInstrumentations. It skips
functions (or loops) that are marked optnone.

The feature of skipping optional passes for optnone functions under NPM
is gated on a -enable-npm-optnone flag. Currently it is by default
false. That is because we still need to mark all required passes to be
required. Otherwise optnone functions will start having incorrect
semantics.  After that is done in following changes, we can remove the
flag and always enable this.

Reviewed By: ychen

Differential Revision: https://reviews.llvm.org/D83519
2020-07-21 09:53:43 -07:00
Zequan Wu 1fbb719470 [LPM] Port CGProfilePass from NPM to LPM
Reviewers: hans, chandlerc!, asbirlea, nikic

Reviewed By: hans, nikic

Subscribers: steven_wu, dexonsmith, nikic, echristo, void, zhizhouy, cfe-commits, aeubanks, MaskRay, jvesely, nhaehnle, hiraditya, kerbowa, llvm-commits

Tags: #llvm, #clang

Differential Revision: https://reviews.llvm.org/D83013
2020-07-10 09:04:51 -07:00
Fangrui Song c025bdf25a Revert D83013 "[LPM] Port CGProfilePass from NPM to LPM"
This reverts commit c92a8c0a0f.

It breaks builds and has unaddressed review comments.
2020-07-09 13:34:04 -07:00
Zequan Wu c92a8c0a0f [LPM] Port CGProfilePass from NPM to LPM
Reviewers: hans, chandlerc!, asbirlea, nikic

Reviewed By: hans, nikic

Subscribers: steven_wu, dexonsmith, nikic, echristo, void, zhizhouy, cfe-commits, aeubanks, MaskRay, jvesely, nhaehnle, hiraditya, kerbowa, llvm-commits

Tags: #llvm, #clang

Differential Revision: https://reviews.llvm.org/D83013
2020-07-09 13:03:42 -07:00
Fangrui Song 2a4317bfb3 [SanitizeCoverage] Rename -fsanitize-coverage-{white,black}list to -fsanitize-coverage-{allow,block}list
Keep deprecated -fsanitize-coverage-{white,black}list as aliases for compatibility for now.

Reviewed By: echristo

Differential Revision: https://reviews.llvm.org/D82244
2020-06-19 22:22:47 -07:00
Alexandre Ganea 89ea0b0520 [MC] Pass down argv0 & cc1 cmd-line to the back-end and store in MCTargetOptions
When targetting CodeView, the goal is to store argv0 & cc1 cmd-line in the emitted .OBJ, in order to allow a reproducer from the .OBJ alone.

This patch is to simplify https://reviews.llvm.org/D80833
2020-06-18 09:17:14 -04:00
Ian Levesque 7c7c8e0da4 [xray] Option to omit the function index
Summary:
Add a flag to omit the xray_fn_idx to cut size overhead and relocations
roughly in half at the cost of reduced performance for single function
patching.  Minor additions to compiler-rt support per-function patching
without the index.

Reviewers: dberris, MaskRay, johnislarry

Subscribers: hiraditya, arphaman, cfe-commits, #sanitizers, llvm-commits

Tags: #clang, #sanitizers, #llvm

Differential Revision: https://reviews.llvm.org/D81995
2020-06-17 13:49:01 -04:00
Arthur Eubanks c07339c675 Move *San module passes later in the NPM pipeline
Summary:
This fixes pr33372.cpp under the new pass manager.

ASan adds padding to globals. For example, it will change a {i32, i32, i32} to a {{i32, i32, i32}, [52 x i8]}. However, when loading from the {i32, i32, i32}, InstCombine may (after various optimizations) end up loading 16 bytes instead of 12, likely because it thinks the [52 x i8] padding is ok to load from. But ASan checks that padding should not be loaded from.

Ultimately this is an issue of *San passes wanting to be run after all optimizations. This change moves the module passes right next to the corresponding function passes.

Also remove comment that's no longer relevant, this is the last ASan/MSan/TSan failure under the NPM (hopefully...).

As mentioned in https://reviews.llvm.org/rG1285e8bcac2c54ddd924ffb813b2b187467ac2a6, NPM doesn't support LTO + sanitizers, so modified some tests that test for that.

Reviewers: leonardchan, vitalybuka

Subscribers: cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D81323
2020-06-08 12:08:49 -07:00
Vitaly Buka 232d348c6e [MTE] Convert StackSafety into analysis
This lets us to remove !stack-safe metadata and
better controll when to perform StackSafety
analysis.

Reviewers: eugenis

Subscribers: hiraditya, steven_wu, dexonsmith, cfe-commits, llvm-commits

Tags: #clang, #llvm

Differential Revision: https://reviews.llvm.org/D80771
2020-06-02 16:08:14 -07:00
Sriraman Tallam e0bca46b08 Options for Basic Block Sections, enabled in D68063 and D73674.
This patch adds clang options:
-fbasic-block-sections={all,<filename>,labels,none} and
-funique-basic-block-section-names.
LLVM Support for basic block sections is already enabled.

+ -fbasic-block-sections={all, <file>, labels, none} : Enables/Disables basic
block sections for all or a subset of basic blocks. "labels" only enables
basic block symbols.
+ -funique-basic-block-section-names: Enables unique section names for
basic block sections, disabled by default.

Differential Revision: https://reviews.llvm.org/D68049
2020-06-02 00:23:32 -07:00
John McCall 8a8d703be0 Fix how cc1 command line options are mapped into FP options.
Canonicalize on storing FP options in LangOptions instead of
redundantly in CodeGenOptions.  Incorporate -ffast-math directly
into the values of those LangOptions rather than considering it
separately when building FPOptions.  Build IR attributes from
those options rather than a mix of sources.

We should really simplify the driver/cc1 interaction here and have
the driver pass down options that cc1 directly honors.  That can
happen in a follow-up, though.

Patch by Michele Scandale!
https://reviews.llvm.org/D80315
2020-06-01 22:00:30 -04:00
Arthur Eubanks 1285e8bcac Run Coverage pass before other *San passes under new pass manager, round 2
Summary:
This was attempted once before in https://reviews.llvm.org/D79698, but
was reverted due to the coverage pass running in the wrong part of the
pipeline. This commit puts it in the same place as the other sanitizers.

This changes PassBuilder.OptimizerLastEPCallbacks to work on a
ModulePassManager instead of a FunctionPassManager. That is because
SanitizerCoverage cannot (easily) be split into a module pass and a
function pass like some of the other sanitizers since in its current
implementation it conditionally inserts module constructors based on
whether or not it successfully modified functions.

This fixes compiler-rt/test/msan/coverage-levels.cpp under the new pass
manager (last check-msan test).

Currently sanitizers + LTO don't work together under the new pass
manager, so I removed tests that checked that this combination works for
sancov.

Subscribers: hiraditya, cfe-commits, llvm-commits

Tags: #clang, #llvm

Differential Revision: https://reviews.llvm.org/D80692
2020-05-28 17:04:47 -07:00
Arthur Eubanks e3fb8446f2 Revert "Run Coverage pass before other *San passes under new pass manager, round 2"
This reverts commit 922fa2fce3.
2020-05-28 14:38:05 -07:00
Arthur Eubanks 922fa2fce3 Run Coverage pass before other *San passes under new pass manager, round 2
Summary:
This was attempted once before in https://reviews.llvm.org/D79698, but
was reverted due to the coverage pass running in the wrong part of the
pipeline. This commit puts it in the same place as the other sanitizers.

This changes PassBuilder.OptimizerLastEPCallbacks to work on a
ModulePassManager instead of a FunctionPassManager. That is because
SanitizerCoverage cannot (easily) be split into a module pass and a
function pass like some of the other sanitizers since in its current
implementation it conditionally inserts module constructors based on
whether or not it successfully modified functions.

This fixes compiler-rt/test/msan/coverage-levels.cpp under the new pass
manager (last check-msan test).

Subscribers: hiraditya, cfe-commits, llvm-commits

Tags: #clang, #llvm

Differential Revision: https://reviews.llvm.org/D80692
2020-05-28 14:25:23 -07:00
Vitaly Buka 2f430f7a51 [StackSafety] Remove SetMetadata parameter 2020-05-28 13:32:57 -07:00
Leonard Chan e9802aa422 Revert "Run Coverage pass before other *San passes under new pass manager"
This reverts commit 7d5bb94d78.

Reverting since this leads to a linker error we're seeing on Fuchsia.
The underlying issue seems to be that inlining is run after sanitizers
and causes different comdat groups instrumented by Sancov to reference
non-key symbols defined in other comdat groups.

Will re-land this patch after a fix for that is landed.
2020-05-14 15:19:27 -07:00
Fangrui Song b56b1e67e3 [gcov] Default coverage version to '408*' and delete CC1 option -coverage-exit-block-before-body
gcov 4.8 (r189778) moved the exit block from the last to the second.
The .gcda format is compatible with 4.7 but

* decoding libgcov 4.7 produced .gcda with gcov [4.7,8) can mistake the
  exit block, emit bogus `%s:'%s' has arcs from exit block\n` warnings,
  and print wrong `" returned %s` for branch statistics (-b).
* decoding libgcov 4.8 produced .gcda with gcov 4.7 has similar issues.

Also, rename "return block" to "exit block" because the latter is the
appropriate term.
2020-05-12 09:14:03 -07:00
Arthur Eubanks 7d5bb94d78 Run Coverage pass before other *San passes under new pass manager
Summary:
This fixes compiler-rt/test/msan/coverage-levels.cpp under the new pass manager (final check-msan test!).
Under the old pass manager, the coverage pass would run before the MSan pass. The opposite happened under the new pass manager. The MSan pass adds extra basic blocks, changing the number of coverage callbacks.

Reviewers: vitalybuka, leonardchan

Subscribers: cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D79698
2020-05-11 12:59:09 -07:00
Fangrui Song 25544ce2df [gcov] Default coverage version to '407*' and delete CC1 option -coverage-cfg-checksum
Defaulting to -Xclang -coverage-version='407*' makes .gcno/.gcda
compatible with gcov [4.7,8)

In addition, delete clang::CodeGenOptionsBase::CoverageExtraChecksum and GCOVOptions::UseCfgChecksum.
We can infer the information from the version.

With this change, .gcda files produced by `clang --coverage a.o` linked executable can be read by gcov 4.7~7.
We don't need other -Xclang -coverage* options.
There may be a mismatching version warning, though.

(Note, GCC r173147 "split checksum into cfg checksum and line checksum"
 made gcov 4.7 incompatible with previous versions.)
2020-05-10 16:14:07 -07:00
Fangrui Song 13a633b438 [gcov] Delete CC1 option -coverage-no-function-names-in-data
rL144865 incorrectly wrote function names for GCOV_TAG_FUNCTION
(this might be part of the reasons the header says
"We emit files in a corrupt version of GCOV's "gcda" file format").

rL176173 and rL177475 realized the problem and introduced -coverage-no-function-names-in-data
to work around the issue. (However, the description is wrong.
libgcov never writes function names, even before GCC 4.2).

In reality, the linker command line has to look like:

clang --coverage -Xclang -coverage-version='407*' -Xclang -coverage-cfg-checksum -Xclang -coverage-no-function-names-in-data

Failing to pass -coverage-no-function-names-in-data can make gcov 4.7~7
either produce wrong results (for one gcov-4.9 program, I see "No executable lines")
or segfault (gcov-7).
(gcov-8 uses an incompatible format.)

This patch deletes -coverage-no-function-names-in-data and the related
function names support from libclang_rt.profile
2020-05-10 12:37:44 -07:00
Jinsong Ji a72b9dfd45 [sanitizer] Enable whitelist/blacklist in new PM
https://reviews.llvm.org/D63616 added `-fsanitize-coverage-whitelist`
and `-fsanitize-coverage-blacklist` for clang.

However, it was done only for legacy pass manager.
This patch enable it for new pass manager as well.

Reviewed By: vitalybuka

Differential Revision: https://reviews.llvm.org/D79653
2020-05-10 02:34:29 +00:00
Simon Pilgrim 0b9783350b LTO.h - reduce includes to forward declarations. NFC.
Add missing ToolOutputFile.h dependency to BackendUtil.cpp
2020-05-09 15:10:51 +01:00
Sriraman Tallam e8147ad822 Uniuqe Names for Internal Linkage Symbols.
This is a standalone patch and this would help Propeller do a better job of code
layout as it can accurately attribute the profiles to the right internal linkage
function.

This also helps SampledFDO/AutoFDO correctly associate sampled profiles to the
right internal function. Currently, if there is more than one internal symbol
foo, their profiles are aggregated by SampledFDO.

This patch adds a new clang option, -funique-internal-funcnames, to generate
unique names for functions with internal linkage. This patch appends the md5
hash of the module name to the function symbol as a best effort to generate a
unique name for symbols with internal linkage.

Differential Revision: https://reviews.llvm.org/D73307
2020-05-07 18:18:37 -07:00
Arthur Eubanks 48451ee6a7 [MSan] Pass MSan command line options under new pass manager
Summary:
Properly forward TrackOrigins and Recover user options to the MSan pass under the new pass manager.
This makes the number of check-msan failures when ENABLE_EXPERIMENTAL_NEW_PASS_MANAGER is TRUE go from 52 to 2.

Based on https://reviews.llvm.org/D77249.

Reviewers: nemanjai, vitalybuka, leonardchan

Subscribers: cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D79445
2020-05-07 08:21:35 -07:00
Melanie Blower c355bec749 Add support for #pragma clang fp reassociate(on|off)
Reviewers: rjmccall, erichkeane, sepavloff

Differential Revision: https://reviews.llvm.org/D78827
2020-05-06 08:05:44 -07:00
Mehdi Amini ed03d9485e Revert "[TLI] Per-function fveclib for math library used for vectorization"
This reverts commit 60c642e74b.

This patch is making the TLI "closed" for a predefined set of VecLib
while at the moment it is extensible for anyone to customize when using
LLVM as a library.
Reverting while we figure out a way to re-land it without losing the
generality of the current API.

Differential Revision: https://reviews.llvm.org/D77925
2020-04-11 01:05:01 +00:00
Matt Morehouse bef187c750 Implement `-fsanitize-coverage-whitelist` and `-fsanitize-coverage-blacklist` for clang
Summary:
This commit adds two command-line options to clang.
These options let the user decide which functions will receive SanitizerCoverage instrumentation.
This is most useful in the libFuzzer use case, where it enables targeted coverage-guided fuzzing.

Patch by Yannis Juglaret of DGA-MI, Rennes, France

libFuzzer tests its target against an evolving corpus, and relies on SanitizerCoverage instrumentation to collect the code coverage information that drives corpus evolution. Currently, libFuzzer collects such information for all functions of the target under test, and adds to the corpus every mutated sample that finds a new code coverage path in any function of the target. We propose instead to let the user specify which functions' code coverage information is relevant for building the upcoming fuzzing campaign's corpus. To this end, we add two new command line options for clang, enabling targeted coverage-guided fuzzing with libFuzzer. We see targeted coverage guided fuzzing as a simple way to leverage libFuzzer for big targets with thousands of functions or multiple dependencies. We publish this patch as work from DGA-MI of Rennes, France, with proper authorization from the hierarchy.

Targeted coverage-guided fuzzing can accelerate bug finding for two reasons. First, the compiler will avoid costly instrumentation for non-relevant functions, accelerating fuzzer execution for each call to any of these functions. Second, the built fuzzer will produce and use a more accurate corpus, because it will not keep the samples that find new coverage paths in non-relevant functions.

The two new command line options are `-fsanitize-coverage-whitelist` and `-fsanitize-coverage-blacklist`. They accept files in the same format as the existing `-fsanitize-blacklist` option <https://clang.llvm.org/docs/SanitizerSpecialCaseList.html#format>. The new options influence SanitizerCoverage so that it will only instrument a subset of the functions in the target. We explain these options in detail in `clang/docs/SanitizerCoverage.rst`.

Consider now the woff2 fuzzing example from the libFuzzer tutorial <https://github.com/google/fuzzer-test-suite/blob/master/tutorial/libFuzzerTutorial.md>. We are aware that we cannot conclude much from this example because mutating compressed data is generally a bad idea, but let us use it anyway as an illustration for its simplicity. Let us use an empty blacklist together with one of the three following whitelists:

```
  # (a)
  src:*
  fun:*

  # (b)
  src:SRC/*
  fun:*

  # (c)
  src:SRC/src/woff2_dec.cc
  fun:*
```

Running the built fuzzers shows how many instrumentation points the compiler adds, the fuzzer will output //XXX PCs//. Whitelist (a) is the instrument-everything whitelist, it produces 11912 instrumentation points. Whitelist (b) focuses coverage to instrument woff2 source code only, ignoring the dependency code for brotli (de)compression; it produces 3984 instrumented instrumentation points. Whitelist (c) focuses coverage to only instrument functions in the main file that deals with WOFF2 to TTF conversion, resulting in 1056 instrumentation points.

For experimentation purposes, we ran each fuzzer approximately 100 times, single process, with the initial corpus provided in the tutorial. We let the fuzzer run until it either found the heap buffer overflow or went out of memory. On this simple example, whitelists (b) and (c) found the heap buffer overflow more reliably and 5x faster than whitelist (a). The average execution times when finding the heap buffer overflow were as follows: (a) 904 s, (b) 156 s, and (c) 176 s.

We explain these results by the fact that WOFF2 to TTF conversion calls the brotli decompression algorithm's functions, which are mostly irrelevant for finding bugs in WOFF2 font reconstruction but nevertheless instrumented and used by whitelist (a) to guide fuzzing. This results in longer execution time for these functions and a partially irrelevant corpus. Contrary to whitelist (a), whitelists (b) and (c) will execute brotli-related functions without instrumentation overhead, and ignore new code paths found in them. This results in faster bug finding for WOFF2 font reconstruction.

The results for whitelist (b) are similar to the ones for whitelist (c). Indeed, WOFF2 to TTF conversion calls functions that are mostly located in SRC/src/woff2_dec.cc. The 2892 extra instrumentation points allowed by whitelist (b) do not tamper with bug finding, even though they are mostly irrelevant, simply because most of these functions do not get called. We get a slightly faster average time for bug finding with whitelist (b), which might indicate that some of the extra instrumentation points are actually relevant, or might just be random noise.

Reviewers: kcc, morehouse, vitalybuka

Reviewed By: morehouse, vitalybuka

Subscribers: pratyai, vitalybuka, eternalsakura, xwlin222, dende, srhines, kubamracek, #sanitizers, lebedev.ri, hiraditya, cfe-commits, llvm-commits

Tags: #clang, #sanitizers, #llvm

Differential Revision: https://reviews.llvm.org/D63616
2020-04-10 10:44:03 -07:00
Wenlei He 60c642e74b [TLI] Per-function fveclib for math library used for vectorization
Summary:
Encode `-fveclib` setting as per-function attribute so it can threaded through to LTO backends. Accordingly per-function TLI now reads
the attributes and select available vector function list based on that. Now we also populate function list for all supported vector
libraries for the shared per-module `TargetLibraryInfoImpl`, so each function can select its available vector list independently but without
duplicating the vector function lists. Inlining between incompatbile vectlib attributed is also prohibited now.

Subscribers: hiraditya, dexonsmith, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D77632
2020-04-09 18:26:38 -07:00
Pratyai Mazumder ced398fdc8 [SanitizerCoverage] Add -fsanitize-coverage=inline-bool-flag
Reviewers: kcc, vitalybuka

Reviewed By: vitalybuka

Subscribers: cfe-commits, llvm-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D77637
2020-04-09 02:40:55 -07:00
zhizhouy 94d912296d [NFC] Do not run CGProfilePass when not using integrated assembler
Summary:
CGProfilePass is run by default in certain new pass manager optimization pipeline. Assemblers other than llvm as (such as gnu as) cannot recognize the .cgprofile entries generated and emitted from this pass, causing build time error.

This patch adds new options in clang CodeGenOpts and PassBuilder options so that we can turn cgprofile off when not using integrated assembler.

Reviewers: Bigcheese, xur, george.burgess.iv, chandlerc, manojgupta

Reviewed By: manojgupta

Subscribers: manojgupta, void, hiraditya, dexonsmith, llvm-commits, tcwang, llozano

Tags: #llvm, #clang

Differential Revision: https://reviews.llvm.org/D62627
2020-03-31 10:31:31 -07:00
Jun Ma d0f4af8f30 [Coroutines] Insert lifetime intrinsics even O0 is used
Differential Revision: https://reviews.llvm.org/D76119
2020-03-24 13:41:55 +08:00
Djordje Todorovic d9b9621009 Reland D73534: [DebugInfo] Enable the debug entry values feature by default
The issue that was causing the build failures was fixed with the D76164.
2020-03-19 13:57:30 +01:00
Evgenii Stepanov 2a3723ef11 [memtag] Plug in stack safety analysis.
Summary:
Run StackSafetyAnalysis at the end of the IR pipeline and annotate
proven safe allocas with !stack-safe metadata. Do not instrument such
allocas in the AArch64StackTagging pass.

Reviewers: pcc, vitalybuka, ostannard

Reviewed By: vitalybuka

Subscribers: merge_guards_bot, kristof.beyls, hiraditya, cfe-commits, gilang, llvm-commits

Tags: #clang, #llvm

Differential Revision: https://reviews.llvm.org/D73513
2020-03-16 16:35:25 -07:00