1792 Commits

Author SHA1 Message Date
Saiyedul Islam
2bfce22a92 [OpenMP] Upgrade default version of OpenMP to 5.0
Summary:
When -fopenmp option is specified then version 5.0 will be set as
default.

Reviewers: gregrodgers, jdoerfert, ABataev

Reviewed By: ABataev

Subscribers: pdhaliwal, yaxunl, guansong, sstefan1, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D81098
2020-06-25 07:13:05 +00:00
Erich Keane
56b530d92c Fix a pair of wtype-limits and 3 wparentheses warnings from 29125ddf1 2020-06-24 12:50:25 -07:00
Daniel Grumberg
29125ddf13 Start adding support for generating CC1 command lines from CompilerInvocation
This change includes the following:
- Add additional information in the relevant table-gen files to encode
the necessary information to automatically parse the argument into a
CompilerInvocation instance and to generate the appropriate command
line argument from a CompilerInvocation instance.
- Extend OptParserEmitter to emit the necessary macro tables as well as
constant tables to support parsing and generating command line
arguments for options that provide the necessary information.
- Port some options to use this new system for parsing and generating
command line arguments.

Differential Revision: https://reviews.llvm.org/D79796
2020-06-24 18:05:05 +01:00
Richard Smith
e135cf8a03 Add -ast-dump-decl-types flag to include types of value and type
declarations in AST dumps.

Includes a testcase for deduction guide transformation that makes use of
this new dumping feature.
2020-06-22 16:47:51 -07:00
Luboš Luňák
a45f713c67 add option to instantiate templates already in the PCH
Add -fpch-instantiate-templates which makes template instantiations be
performed already in the PCH instead of it being done in every single
file that uses the PCH (but every single file will still do it as well
in order to handle its own instantiations). I can see 20-30% build
time saved with the few tests I've tried.

The change may reorder compiler output and also generated code, but
should be generally safe and produce functionally identical code.
There are some rare cases that do not compile with it,
such as test/PCH/pch-instantiate-templates-forward-decl.cpp. If
template instantiation bailed out instead of reporting the error,
these instantiations could even be postponed, which would make them
work.

Enable this by default for clang-cl. MSVC creates PCHs by compiling
them using an empty .cpp file, which means templates are instantiated
while building the PCH and so the .h needs to be self-contained,
making test/PCH/pch-instantiate-templates-forward-decl.cpp to fail
with MSVC anyway. So the option being enabled for clang-cl matches this.

Differential Revision: https://reviews.llvm.org/D69585
2020-06-21 17:05:52 +02:00
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
Haojian Wu
58ea1059df [AST][RecoveryExpr] Build recovery expressions by default for C++.
Reland https://reviews.llvm.org/D76696
All known crashes have been fixed, another attemption.

We have rolled out this to all internal users for a while, didn't see
big issues, we consider it is stable enough.

Reviewed By: sammccall

Subscribers: rsmith, hubert.reinterpretcast, ebevhan, jkorous, arphaman, kadircet, usaxena95, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D78350
2020-06-12 15:21:38 +02:00
Leonard Chan
71568a9e28 [clang] Frontend components for the relative vtables ABI (round 2)
This patch contains all of the clang changes from D72959.

- Generalize the relative vtables ABI such that it can be used by other targets.
- Add an enum VTableComponentLayout which controls whether components in the
  vtable should be pointers to other structs or relative offsets to those structs.
  Other ABIs can change this enum to restructure how components in the vtable
  are laid out/accessed.
- Add methods to ConstantInitBuilder for inserting relative offsets to a
  specified position in the aggregate being constructed.
- Fix failing tests under new PM and ASan and MSan issues.

See D72959 for background info.

Differential Revision: https://reviews.llvm.org/D77592
2020-06-11 11:17:08 -07:00
Leonard Chan
7201272d4c Revert "[clang] Frontend components for the relative vtables ABI"
This reverts commit 2e009dbcb3e373a59e6e84dce6d51ae8a29f60a5.

Reverting since there were some test failures on buildbots that used the
new pass manager. ASan and MSan are also finding some bugs in this that
I'll need to address.
2020-06-10 13:50:05 -07:00
Leonard Chan
2e009dbcb3 [clang] Frontend components for the relative vtables ABI
This patch contains all of the clang changes from D72959.

- Generalize the relative vtables ABI such that it can be used by other targets.
- Add an enum VTableComponentLayout which controls whether components in the
  vtable should be pointers to other structs or relative offsets to those structs.
  Other ABIs can change this enum to restructure how components in the vtable
  are laid out/accessed.
- Add methods to ConstantInitBuilder for inserting relative offsets to a
  specified position in the aggregate being constructed.

See D72959 for background info.

Differential Revision: https://reviews.llvm.org/D77592
2020-06-10 12:48:10 -07:00
Jian Cai
4db2b70248 Add a flag to debug automatic variable initialization
Summary:
Add -ftrivial-auto-var-init-stop-after= to limit the number of times
stack variables are initialized when -ftrivial-auto-var-init= is used to
initialize stack variables to zero or a pattern. This flag can be used
to bisect uninitialized uses of a stack variable exposed by automatic
variable initialization, such as http://crrev.com/c/2020401.

Reviewers: jfb, vitalybuka, kcc, glider, rsmith, rjmccall, pcc, eugenis, vlad.tsyrklevich

Reviewed By: jfb

Subscribers: phosek, hubert.reinterpretcast, srhines, MaskRay, george.burgess.iv, dexonsmith, inglorion, gbiv, llozano, manojgupta, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D77168
2020-06-08 12:30:56 -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
Saiyedul Islam
602d9b0afc [OpenMP][AMDGCN] Support OpenMP offloading for AMDGCN architecture - Part 1
Summary:
Allow AMDGCN as a GPU offloading target for OpenMP during compiler
invocation and allow setting CUDAMode for it.

Originally authored by Greg Rodgers (@gregrodgers).

Reviewers: ronlieb, yaxunl, b-sumner, scchan, JonChesterfield, jdoerfert, sameerds, msearles, hliao, arsenm

Reviewed By: sameerds

Subscribers: sstefan1, jvesely, wdng, arsenm, guansong, dexonsmith, cfe-commits, llvm-commits, gregrodgers

Tags: #clang, #llvm

Differential Revision: https://reviews.llvm.org/D79754
2020-05-27 07:51:27 +00:00
Fangrui Song
9d55e4ee13 Make explicit -fno-semantic-interposition (in -fpic mode) infer dso_local
-fno-semantic-interposition is currently the CC1 default. (The opposite
disables some interprocedural optimizations.) However, it does not infer
dso_local: on most targets accesses to ExternalLinkage functions/variables
defined in the current module still need PLT/GOT.

This patch makes explicit -fno-semantic-interposition infer dso_local,
so that PLT/GOT can be eliminated if targets implement local aliases
for AsmPrinter::getSymbolPreferLocal (currently only x86).

Currently we check whether the module flag "SemanticInterposition" is 0.
If yes, infer dso_local. In the future, we can infer dso_local unless
"SemanticInterposition" is 1: frontends other than clang will also
benefit from the optimization if they don't bother setting the flag.
(There will be risks if they do want ELF interposition: they need to set
"SemanticInterposition" to 1.)
2020-05-25 20:48:18 -07:00
Melanie Blower
827be690dc [clang] FastMathFlags.allowContract should be initialized only from FPFeatures.allowFPContractAcrossStatement
Summary: Fix bug introduced in D72841 adding support for pragma float_control

Reviewers: rjmccall, Anastasia

Differential Revision: https://reviews.llvm.org/D79903
2020-05-20 06:19:10 -07:00
Dávid Bolvanský
47650dcbee Revert "[clang-misexpect] Fixed typo which causes that --pgo-warn-misexpect option is not passed in the compiler invocation"
This reverts commit 6d2b75e0887ee87e247756c4d51733616bb2f356.
2020-05-19 23:20:54 +02:00
Dávid Bolvanský
6d2b75e088 [clang-misexpect] Fixed typo which causes that --pgo-warn-misexpect option is not passed in the compiler invocation 2020-05-19 23:12:08 +02:00
jasonliu
7f5d91d3ff [clang][AIX] Implement ABIInfo and TargetCodeGenInfo for AIX
Summary:
Created AIXABIInfo and AIXTargetCodeGenInfo for AIX ABI.

Reviewed By: Xiangling_L, ZarkoCA

Differential Revision: https://reviews.llvm.org/D79035
2020-05-19 15:00:48 +00:00
Fangrui Song
82904401e3 Map -O to -O1 instead of -O2
rL82131 changed -O from -O1 to -O2, because -O1 was not different from
-O2 at that time.

GCC treats -O as -O1 and there is now work to make -O1 meaningful.
We can change -O back to -O1 again.

Reviewed By: echristo, dexonsmith, arphaman

Differential Revision: https://reviews.llvm.org/D79916
2020-05-18 15:53:41 -07:00
Djordje Todorovic
170ac4be33 [CSInfo][ISEL] Call site info generation support for Mips
Debug entry values functionality provides debug information about
call sites and function parameters values at the call entry spot.
Condition for generating this type of information is
compiling with -g option and optimization level higher
than zero(-O0).

In ISEL phase, while lowering call instructions, collect info
about registers that forward arguments into following
function frame. We store such info into MachineFunction of
the caller function. This is used very late, when dumping DWARF
info about call site parameters.

The call site info is visible at MIR level, as callSites attribute
of MachineFunction. Also, when using unmodified parameter value
inside callee it could be described as DW_OP_entry_value expression.
To deal with callSites attribute, we should pass
-emit-call-site-info option to llc.

This patch enables functionality in clang frontend and adds
call site info generation support for MIPS targets
(mips, mipsel, mips64, mips64el).

Patch by Nikola Tesic

Differential Revision: https://reviews.llvm.org/D78105
2020-05-15 10:13:15 +02:00
Volodymyr Sapsai
6a3469f58d [ObjC] Add compatibility mode for type checking of qualified id block parameters.
Commit 73152a2ec20766ac45673a129bf1f5fc97ca9bbe fixed type checking for
blocks with qualified id parameters. But there are existing APIs in
Apple SDKs relying on the old type checking behavior. Specifically,
these are APIs using NSItemProviderCompletionHandler in
Foundation/NSItemProvider.h. To keep existing code working and to allow
developers to use affected APIs introduce a compatibility mode that
enables the previous and the fixed type checking. This mode is enabled
only on Darwin platforms.

Reviewed By: jyknight, ahatanak

Differential Revision: https://reviews.llvm.org/D79511
2020-05-14 12:08:19 -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
Zola Bridges
379e68a763 [clang][SLH] Add __has_feature(speculative_load_hardening)
SLH doesn't support asm goto and is unlikely to ever support it. Users of asm
goto need a way to choose whether to use asm goto or fallback to an SLH
compatible code path when SLH is enabled. This feature flag will give users
this ability.

Tested via unit test

Reviewed By: mattdr

Differential Revision: https://reviews.llvm.org/D79733
2020-05-11 13:37:12 -07:00
Melanie Blower
01dc694ccb FP LangOpts should not be dependent on CGOpt
This bug was observed by Apple since their compiler processes LangOpts and CGOpts in a different order.

Reviewed By: rjmccall

Differential Revision: https://reviews.llvm.org/D79735
2020-05-11 12:32:35 -07:00
Florian Hahn
1065869195 [Matrix] Add matrix type to Clang.
This patch adds a matrix type to Clang as described in the draft
specification in clang/docs/MatrixSupport.rst. It introduces a new option
-fenable-matrix, which can be used to enable the matrix support.

The patch adds new MatrixType and DependentSizedMatrixType types along
with the plumbing required. Loads of and stores to pointers to matrix
values are lowered to memory operations on 1-D IR arrays. After loading,
the loaded values are cast to a vector. This ensures matrix values use
the alignment of the element type, instead of LLVM's large vector
alignment.

The operators and builtins described in the draft spec will will be added in
follow-up patches.

Reviewers: martong, rsmith, Bigcheese, anemet, dexonsmith, rjmccall, aaron.ballman

Reviewed By: rjmccall

Differential Revision: https://reviews.llvm.org/D72281
2020-05-11 18:55:45 +01:00
Haojian Wu
8222107aa9 [AST] Preserve the type in RecoveryExprs for broken function calls.
RecoveryExprs are modeled as dependent type to prevent bogus diagnostics
and crashes in clang.

This patch allows to preseve the type for broken calls when the
RecoveryEprs have a known type, e.g. a broken non-overloaded call, a
overloaded call when the all candidates have the same return type, so
that more features (code completion still work on "take2args(x).^") still
work.

However, adding the type is risky, which may result in more clang code being
affected leading to new crashes and hurt diagnostic, and it requires large
effort to minimize the affect (update all sites in clang to handle errorDepend
case), so we add a new flag (off by default) to allow us to develop/test
them incrementally.

This patch also has some trivial fixes to suppress diagnostics (to prevent regressions).

Tested:

all existing tests are passed (when both "-frecovery-ast", "-frecovery-ast-type" flags are flipped on);

Reviewed By: sammccall

Subscribers: rsmith, arphaman, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D79160
2020-05-11 08:46:18 +02:00
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
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
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
Melanie Blower
f5360d4bb3 Reapply "Add support for #pragma float_control" with buildbot fixes
Add support for #pragma float_control

Reviewers: rjmccall, erichkeane, sepavloff

Differential Revision: https://reviews.llvm.org/D72841

This reverts commit fce82c0ed310174fe48e2402ac731b6340098389.
2020-05-04 05:51:25 -07:00
Melanie Blower
fce82c0ed3 Revert "Reapply "Add support for #pragma float_control" with improvements to"
This reverts commit 69aacaf699922ffe0450f567e21208c10c84731f.
2020-05-01 10:31:09 -07:00
Melanie Blower
69aacaf699 Reapply "Add support for #pragma float_control" with improvements to
test cases
Add support for #pragma float_control

Reviewers: rjmccall, erichkeane, sepavloff

Differential Revision: https://reviews.llvm.org/D72841

This reverts commit 85dc033caccaa6ab919d57f9759290be41240146, and makes
corrections to the test cases that failed on buildbots.
2020-05-01 10:03:30 -07:00
Melanie Blower
85dc033cac Revert "Add support for #pragma float_control"
This reverts commit 4f1e9a17e9d28bdfd035313c96b3a5d4c91a7733.
due to fail on buildbot, sorry for the noise
2020-05-01 06:36:58 -07:00
Melanie Blower
4f1e9a17e9 Add support for #pragma float_control
Reviewers: rjmccall, erichkeane, sepavloff

Differential Revision: https://reviews.llvm.org/D72841
2020-05-01 06:14:24 -07:00
Dmitri Gribenko
96717125e8 Revert "[analyzer] On-demand parsing capability for CTU"
This reverts commit 811c0c9eb462d1fef6ab6908aab7881e5c4f5fbf. It broke
multiple buildbots.
2020-04-27 14:27:04 +02:00
Endre Fülöp
811c0c9eb4 [analyzer] On-demand parsing capability for CTU
Summary:
Add an option to enable on-demand parsing of needed ASTs during CTU analysis.
Two options are introduced. CTUOnDemandParsing enables the feature, and
CTUOnDemandParsingDatabase specifies the path to a compilation database, which
has all the necessary information to generate the ASTs.

Reviewers: martong, balazske, Szelethus, xazax.hun

Subscribers: ormris, mgorny, whisperity, xazax.hun, baloghadamsoftware, szepet, rnkovacs, a.sidorin, mikhail.ramalho, Szelethus, donat.nagy, dkrupp, Charusso, steakhal, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D75665
2020-04-27 11:20:35 +02:00
Fangrui Song
8d45d6e39d [Frontend] Drop unneeded CC1 options 2020-04-21 19:59:28 -07:00
Justin Hibbits
4ca2cad947 [PowerPC] Add clang -msvr4-struct-return for 32-bit ELF
Summary:

Change the default ABI to be compatible with GCC.  For 32-bit ELF
targets other than Linux, Clang now returns small structs in registers
r3/r4.  This affects FreeBSD, NetBSD, OpenBSD.  There is no change for
32-bit Linux, where Clang continues to return all structs in memory.

Add clang options -maix-struct-return (to return structs in memory) and
-msvr4-struct-return (to return structs in registers) to be compatible
with gcc.  These options are only for PPC32; reject them on PPC64 and
other targets.  The options are like -fpcc-struct-return and
-freg-struct-return for X86_32, and use similar code.

To actually return a struct in registers, coerce it to an integer of the
same size.  LLVM may optimize the code to remove unnecessary accesses to
memory, and will return i32 in r3 or i64 in r3:r4.

Fixes PR#40736

Patch by George Koehler!

Reviewed By: jhibbits, nemanjai
Differential Revision: https://reviews.llvm.org/D73290
2020-04-21 20:17:25 -05:00
Aaron Ballman
6a30894391 C++2a -> C++20 in some identifiers; NFC. 2020-04-21 15:37:19 -04:00
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
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
Serge Pavlov
c7ff5b38f2 [FPEnv] Use single enum to represent rounding mode
Now compiler defines 5 sets of constants to represent rounding mode.
These are:

1. `llvm::APFloatBase::roundingMode`. It specifies all 5 rounding modes
defined by IEEE-754 and is used in `APFloat` implementation.

2. `clang::LangOptions::FPRoundingModeKind`. It specifies 4 of 5 IEEE-754
rounding modes and a special value for dynamic rounding mode. It is used
in clang frontend.

3. `llvm::fp::RoundingMode`. Defines the same values as
`clang::LangOptions::FPRoundingModeKind` but in different order. It is
used to specify rounding mode in in IR and functions that operate IR.

4. Rounding mode representation used by `FLT_ROUNDS` (C11, 5.2.4.2.2p7).
Besides constants for rounding mode it also uses a special value to
indicate error. It is convenient to use in intrinsic functions, as it
represents platform-independent representation for rounding mode. In this
role it is used in some pending patches.

5. Values like `FE_DOWNWARD` and other, which specify rounding mode in
library calls `fesetround` and `fegetround`. Often they represent bits
of some control register, so they are target-dependent. The same names
(not values) and a special name `FE_DYNAMIC` are used in
`#pragma STDC FENV_ROUND`.

The first 4 sets of constants are target independent and could have the
same numerical representation. It would simplify conversion between the
representations. Also now `clang::LangOptions::FPRoundingModeKind` and
`llvm::fp::RoundingMode` do not contain the value for IEEE-754 rounding
direction `roundTiesToAway`, although it is supported natively on
some targets.

This change defines all the rounding mode type via one `llvm::RoundingMode`,
which also contains rounding mode for IEEE rounding direction `roundTiesToAway`.

Differential Revision: https://reviews.llvm.org/D77379
2020-04-09 13:26:47 +07:00
Daniel Kiss
7314aea5a4 [clang] Move branch-protection from CodeGenOptions to LangOptions
Summary:
Reason: the option has an effect on preprocessing.

Also see thread: http://lists.llvm.org/pipermail/cfe-dev/2020-March/065014.html

Reviewers: chill, efriedma

Reviewed By: efriedma

Subscribers: efriedma, danielkiss, cfe-commits, kristof.beyls

Tags: #clang

Differential Revision: https://reviews.llvm.org/D77131
2020-04-02 10:31:52 +02:00
Puyan Lotfi
e3033c0ce5 [llvm][clang][IFS] Enhancing the llvm-ifs yaml format for symbol lists.
Prior to this change the clang interface stubs format resembled
something ending with a symbol list like this:

 Symbols:
   a: { Type: Func }

This was problematic because we didn't actually want a map format and
also because we didn't like that an empty symbol list required
"Symbols: {}". That is to say without the empty {} llvm-ifs would crash
on an empty list.

With this new format it is much more clear which field is the symbol
name, and instead the [] that is used to express an empty symbol vector
is optional, ie:

Symbols:
 - { Name: a, Type: Func }

or

Symbols: []

or

Symbols:

This further diverges the format from existing llvm-elftapi. This is a
good thing because although the format originally came from the same
place, they are not the same in any way.

Differential Revision: https://reviews.llvm.org/D76979
2020-04-01 10:49:06 -04:00
Fangrui Song
531b3aff30 [Frontend] Replace CC1 option -masm-verbose with -fno-verbose-asm
Most OS✕target enable -fverbose-asm, so it makes sense to flip the CC1
option to reduce common command lines.
2020-03-31 22:33:55 -07:00
Fangrui Song
d0d076fed9 [Driver] Flip the CC1 default of -fdiagnostics-show-option
The driver enables -fdiagnostics-show-option by default, so flip the CC1
default to reduce the lengths of common CC1 command lines.

This change also makes ParseDiagnosticArgs() consistently enable
-fdiagnostics-show-option by default.
2020-03-31 21:59:27 -07:00