Commit Graph

645 Commits

Author SHA1 Message Date
Marcos Pividori 6a7e4c2e20 [libFuzzer] Update tests to use more general functions instead of posix specific.
Replace sleep() posix function by a more portable sleep_for() function
from std. Also, ignore memmem() and strcasestr() on Windows.

Differential Revision: https://reviews.llvm.org/D27729

llvm-svn: 289964
2016-12-16 17:35:13 +00:00
Kostya Serebryany 628b43aab6 [libFuzzer] enable the failure-resistant merge by default (with trace-pc-guard only)
llvm-svn: 289772
2016-12-15 06:21:21 +00:00
Kostya Serebryany d9d9a54511 [libFuzzer] disable msan for one more hook that reads target's data that might be uninitialized
llvm-svn: 289680
2016-12-14 18:13:02 +00:00
Kostya Serebryany f6f82c2cc8 [libFuzzer] fix an UB (invalid shift) spotted by ubsan. The code worked fine by luck, because the way shifts actually work on clang+x86
llvm-svn: 289607
2016-12-13 22:49:14 +00:00
Marcos Pividori c21b3c949d [libFuzzer] Add missing header needed for Windows.
llvm-svn: 289564
2016-12-13 17:46:48 +00:00
Marcos Pividori 7c1defd738 [libFuzzer] Avoid name collision with Windows API.
Windows uses some macros to replace DeleteFile() by DeleteFileA() or
DeleteFileW(). This was causing an error at link time.
DeleteFile was renamed to RemoveFile().

Differential Revision: https://reviews.llvm.org/D27577

llvm-svn: 289563
2016-12-13 17:46:40 +00:00
Marcos Pividori 67dfacdd80 [libFuzzer] Implement DirName() for Windows.
Implement DirName from scratch to avoid dependencies on external libraries.
It's based on MSDN documentation for Naming Files, Paths, and Namespaces.

The algorithm can't simply start from the end and look backwards for the
first separator, because we need to preserve the prefix that represent
the root location. We shouldn't remove anything there. In Windows we
have many different options, like:
 \\Server\Share\ , \ , C: , C:\ , \\?\C:\ , \\?\UNC\Server\Share\
We remove the last separator in the rest of the path, if it exists.

It was implemented to have a similar behaviour to dirname() in linux,
removing trailing separators, returning "." when the path doesn't
contain separators, etc.

Differential Revision: https://reviews.llvm.org/D27579

llvm-svn: 289562
2016-12-13 17:46:32 +00:00
Marcos Pividori 64d4147396 [libFuzzer] Fix bug in detecting timeouts when input string is empty.
I added a new flag RunningCB to know if the Fuzzer's main thread is
running the CB function, instead of using (!CurrentUnitSize).
(!CurrentUnitSize) doesn't work properly. For example, in FuzzerLoop.cpp,
inside ShuffleAndMinimize() function, we execute the callback with an
empty string (size=0). Previous implementation failed to detect timeouts
in that execution.
Also, I add a regression test for that case.

Differential Revision: https://reviews.llvm.org/D27433

llvm-svn: 289561
2016-12-13 17:46:25 +00:00
Marcos Pividori 178fe58745 [libFuzzer] Clean up headers and file formatting of LibFuzzer files.
Reorganize #includes to follow LLVM Coding Standards.
Include some missing headers. Required to use `Printf()`.

Aside from that, this patch contains no functional change.
It is purely a re-organization.

Differential Revision: https://reviews.llvm.org/D27363

llvm-svn: 289560
2016-12-13 17:46:11 +00:00
Marcos Pividori 6e3d885c79 [libFuzzer] Properly use unsigned for workers, jobs and NumberOfCpuCores.
std:🧵:hardware_concurrency() returns an unsigned, so I modify
NumberOfCpuCores() to return unsigned too.
The number of cpus is used to define the number of workers, so I decided
to update the worker and jobs flags to be declared as unsigned too.

Differential Revision: https://reviews.llvm.org/D27685

llvm-svn: 289559
2016-12-13 17:45:53 +00:00
Marcos Pividori 463f8bdd0b [libFuzzer] Properly use unsigned for Process ID.
Use unsigned for PID instead of signed int. GetCurrentProcessId() returns
an unsigned (DWORD) so we must be sure we can deal with all possible values.
I use a long unsigned to be sure it can hold a 32 bit unsigned (DWORD).

Differential Revision: https://reviews.llvm.org/D27281

llvm-svn: 289558
2016-12-13 17:45:44 +00:00
Marcos Pividori c59b692c85 [libFuzzer] Improve Signal Handler interface.
Add new flags to FuzzingOptions to represent the different conditions
on the signal handling. These options are passed when calling
SetSignalHandler().
This changes simplify the implementation of Windows's exception
handling. Now we can define a unique handler for all the exceptions.

Differential Revision: https://reviews.llvm.org/D27238

llvm-svn: 289557
2016-12-13 17:45:20 +00:00
Kostya Serebryany a31300e789 [libFuzzer] don't require extra flags with -minimize_crash=1 (default to -max_total_time=600). Also respect exact_artifact_path when outputting the end result
llvm-svn: 289506
2016-12-13 00:40:47 +00:00
Marcos Pividori 681e904419 [libFuzzer] Implement Timers for Windows.
Implemented timeouts for Windows using TimerQueueTimers.
Timers are used to supervise the time of execution of the
callback function that is being fuzzed.

Differential Revision: https://reviews.llvm.org/D27237

llvm-svn: 289495
2016-12-12 23:25:11 +00:00
Kostya Serebryany 092d5764a1 [libFuzzer] split one slow test into several, for more parallel testing
llvm-svn: 289481
2016-12-12 22:55:25 +00:00
Kostya Serebryany a4b43bf8e8 [libFuzzer] make SimpleCmpTest a bit simpler to crack and more verbose
llvm-svn: 289477
2016-12-12 22:39:33 +00:00
Kostya Serebryany 035af9b346 [libFuzzer] build libFuzzer itself with asan
llvm-svn: 289469
2016-12-12 20:58:10 +00:00
Kostya Serebryany d4be88913e [libFuzzer] respect -max_len during merge
llvm-svn: 289467
2016-12-12 20:39:35 +00:00
Kostya Serebryany 441e6310ae [libFuzzer] don't depend on time in a test
llvm-svn: 289368
2016-12-11 06:28:09 +00:00
Kostya Serebryany c05cb60369 [libFuzzer] test cleanup (3)
llvm-svn: 289314
2016-12-10 02:48:42 +00:00
Kostya Serebryany 832d39e9cc [libFuzzer] test cleanup (2)
llvm-svn: 289313
2016-12-10 02:47:00 +00:00
Kostya Serebryany 2f962fe5f7 [libFuzzer] test cleanup
llvm-svn: 289312
2016-12-10 02:45:56 +00:00
Kostya Serebryany 61be0f947d [libFuzzer] switch all libFuzzer tests to use -fsanitize-coverage=trace-pc-guard. Support for the previosly used instrumentation will be removed in the following changes
llvm-svn: 289311
2016-12-10 02:26:23 +00:00
Kostya Serebryany 1394ce2aa2 [libFuzzer] use __sanitizer_get_module_and_offset_for_pc to get the module name while printing the coverage
llvm-svn: 289310
2016-12-10 01:19:35 +00:00
Kostya Serebryany 111e1d69e3 [libFuzzer] implement crash-resistant merge (https://github.com/google/sanitizers/issues/722). This is a first experimental variant that needs some more testing, thus not yet adding a lit test (but there are unit tests).
llvm-svn: 289166
2016-12-09 01:17:24 +00:00
Kostya Serebryany 64a055549a [libFuzzer] include FuzzerIO.h and hopefully fix the Mac build. reported by Dejan Mircevski
llvm-svn: 288979
2016-12-07 21:02:48 +00:00
Kostya Serebryany fe1094b811 [libFuzzer] refactor the code to allow collecting features in different ways. Also initialize a couple of Fuzzer:: members that might have been used uninitialized :(
llvm-svn: 288731
2016-12-05 23:35:22 +00:00
Zachary Turner 6fa57ad9bd Resubmit "[LibFuzzer] Split FuzzerUtil for Posix and Windows."
This resubmits r288529, which was resubmitted because it broke a
fuzzer bot.  According to kcc@ the test that broke was flakey
and it is unlikely to be a result of this patch.

llvm-svn: 288549
2016-12-02 23:02:01 +00:00
Zachary Turner 3cfeab7059 Revert "[LibFuzzer] Split FuzzerUtil for Posix and Windows."
This reverts commit r288529, as it seems to introduce some
problems on the Linux bots.

llvm-svn: 288533
2016-12-02 20:54:56 +00:00
Zachary Turner d755e4f587 [LibFuzzer] Introduce a portable WeakAlias implementation.
Windows doesn't really support weak aliases, but with some
linker magic we can get something that's pretty close on
Windows.  This introduces an interface to accessing weakly
aliased symbols that will work on any platform.  Linker
magic changes to come in a separate patch.

Patch by Marcos Pividori
Differential Revision: https://reviews.llvm.org/D27235

llvm-svn: 288530
2016-12-02 19:41:17 +00:00
Zachary Turner 34dcfb9294 [LibFuzzer] Split FuzzerUtil for Posix and Windows.
Pave the way for separating out platform specific
utility functions into separate files.

Patch by Marcos Pividori
Differential Revision: https://reviews.llvm.org/D27234

llvm-svn: 288529
2016-12-02 19:38:19 +00:00
Kostya Serebryany 09f4fa5200 [libFuzzer] add a test for r288389 (-rss_limit_mb=0 means no limit).
llvm-svn: 288392
2016-12-01 18:02:07 +00:00
Kostya Serebryany dc6b8ca879 [libFuzzer] treat -rss_limit_mb=0 as no limit
llvm-svn: 288389
2016-12-01 17:56:15 +00:00
Kostya Serebryany b66cb88c2e revert r288283 as it causes debug info (line numbers) to be lost in instrumented code. also revert r288299 which was a workaround for the problem.
llvm-svn: 288300
2016-12-01 02:06:56 +00:00
Kostya Serebryany 73f438ef9a [libFuzzer] temporary disable a part of the test broken by r288283
llvm-svn: 288299
2016-12-01 01:33:44 +00:00
Kostya Serebryany 05f7791fbf [libFuzzer] extend -rss_limit_mb to crash instantly on a single malloc that exceeds the limit
llvm-svn: 288281
2016-11-30 22:39:35 +00:00
Kostya Serebryany 1cba0a96e7 [libFuzzer] extend -print_coverage to print the comma-separated list of covered dirs. Note: the Windows stub for DirName is left unimplemented
llvm-svn: 288276
2016-11-30 21:53:32 +00:00
Zachary Turner 5abac1769f [LibFuzzer] Add Windows implementations of some IO functions.
This patch moves some posix specific file i/o code into a new
file, FuzzerIOPosix.cpp, and provides implementations for these
functions on Windows in FuzzerIOWindows.cpp.  This is another
incremental step towards getting libfuzzer working on Windows,
although it still should not be expected to be fully working.

Patch by Marcos Pividori
Differential Revision: https://reviews.llvm.org/D27233

llvm-svn: 288275
2016-11-30 21:44:26 +00:00
Zachary Turner 24a148b1d4 [LibFuzzer] Split up some functions among different headers.
In an effort to get libfuzzer working on Windows, we need to make
a distinction between what functions require platform specific
code (e.g. different code on Windows vs Linux) and what code
doesn't.  IO functions, for example, tend to be platform
specific.

This patch separates out some of the functions which will need
to have platform specific implementations into different headers,
so that we can then provide different implementations for each
platform.

Aside from that, this patch contains no functional change.  It
is purely a re-organization.

Patch by Marcos Pividori
Differential Revision: https://reviews.llvm.org/D27230

llvm-svn: 288264
2016-11-30 19:06:14 +00:00
Zachary Turner c6d8b4c044 [LibFuzzer] Add macro flags for Posix and Windows.
This is the beginning of an effort to get libfuzzer working on
Windows.  This is a NFC to just add some macros for platform
detection on Windows.

Patch by Marcos Pividori
Differential Revision: https://reviews.llvm.org/D27229

llvm-svn: 288249
2016-11-30 16:32:54 +00:00
Kostya Serebryany 6c77811a29 [libFuzzer] replace 'auto' with 'auto *' to better follow the LLVM style
llvm-svn: 286870
2016-11-14 19:21:38 +00:00
Kostya Serebryany 53c894d257 [libFuzzer] use a valid ASCII string for a dummy seed corpus
llvm-svn: 286702
2016-11-12 02:27:21 +00:00
Kostya Serebryany fc1c405f98 [libFuzzer] use less stack
llvm-svn: 286689
2016-11-12 00:24:35 +00:00
Kostya Serebryany 235679181b [libFuzzer] do not initialize parts of TracePC -- let them be initialized by the linker. Add no-msan attribute to the memcmp hook.
llvm-svn: 286665
2016-11-11 23:06:53 +00:00
Kostya Serebryany 8a56917492 [libFuzzer] fix -error_exitcode=N, now with a test
llvm-svn: 285958
2016-11-03 19:31:18 +00:00
Kostya Serebryany bcfb0802e2 [libFuzzer] enable use_cmp by default
llvm-svn: 285353
2016-10-27 21:44:37 +00:00
Kostya Serebryany 94c427c23e [libFuzzer] speculatively trying to fix the Mac build; second attempt
llvm-svn: 285262
2016-10-27 00:36:38 +00:00
Kostya Serebryany 3d945f6247 [libFuzzer] revert 285259 -- hit commit too soon
llvm-svn: 285260
2016-10-27 00:24:34 +00:00
Kostya Serebryany 15cd6b4b10 [libFuzzer] speculatively trying to fix the Mac build
llvm-svn: 285259
2016-10-27 00:22:39 +00:00
Kostya Serebryany 2fabecaee3 [libFuzzer] simplify TracePC::HandleTrace even further. Also, when dealing with -exit_on_src_pos, symbolize every PC only once
llvm-svn: 285223
2016-10-26 18:52:04 +00:00
Kostya Serebryany 06b8757b57 [libFuzzer] simplify the code in TracePC::HandleTrace a bit more
llvm-svn: 285147
2016-10-26 00:42:52 +00:00
Kostya Serebryany a5b2e54fcb [libFuzzer] simplify the code to print new PCs
llvm-svn: 285145
2016-10-26 00:20:51 +00:00
Kostya Serebryany 275e260258 [libFuzzer] simplify the code in TracePC::HandleTrace
llvm-svn: 285142
2016-10-25 23:52:25 +00:00
Kostya Serebryany 117976818e [libFuzzer] add StandaloneFuzzTargetMain.c and a test for it
llvm-svn: 285135
2016-10-25 22:30:34 +00:00
Kostya Serebryany c48c93184a [libFuzzer] when mutating based on CMP traces also try adding +/- 1 to the desired bytes. Add another test for use_cmp
llvm-svn: 285109
2016-10-25 20:15:15 +00:00
Kostya Serebryany 3364f90783 [libFuzzer] simplify the code for use_cmp, also use the position hint when available, add a test
llvm-svn: 285049
2016-10-25 02:04:43 +00:00
Kostya Serebryany 65f102d4d2 [libFuzzer] mutation: insert the size of the input in bytes as one of the ways to mutate a binary integer
llvm-svn: 284909
2016-10-22 03:48:53 +00:00
Kostya Serebryany 10ae9e23a3 [libFuzzer] typo in a test
llvm-svn: 284903
2016-10-22 01:07:38 +00:00
Kostya Serebryany 2bfff021ad [libFuzzer] add a test for asan's strict_string_checks=1
llvm-svn: 284902
2016-10-22 00:05:44 +00:00
Reid Kleckner ac2a2a86e4 Fix -Wunused-variable warning in libFuzzer
llvm-svn: 284838
2016-10-21 16:26:27 +00:00
Kostya Serebryany 95b1a434d2 [libFuzzer] extend -print_coverage to also print uncovered lines, functions, and files.
Example of output:
COVERAGE:
COVERED: in DSO2(int) /pathto/DSO2.cpp:6
COVERED: in DSO2(int) /pathto/DSO2.cpp:8
COVERED: in DSO1(int) /pathto/DSO1.cpp:6
COVERED: in DSO1(int) /pathto/DSO1.cpp:8
COVERED: in LLVMFuzzerTestOneInput /pathto/DSOTestMain.cpp:16
COVERED: in LLVMFuzzerTestOneInput /pathto/DSOTestMain.cpp:19
COVERED: in LLVMFuzzerTestOneInput /pathto/DSOTestMain.cpp:25
COVERED: in LLVMFuzzerTestOneInput /pathto/DSOTestMain.cpp:26
MODULE_WITH_COVERAGE: /pathto/libLLVMFuzzer-DSO1.so
UNCOVERED_LINE: in DSO1(int) /pathto/DSO1.cpp:9
UNCOVERED_FUNC: in Uncovered1()
MODULE_WITH_COVERAGE: /pathto/libLLVMFuzzer-DSO2.so
UNCOVERED_LINE: in DSO2(int) /pathto/DSO2.cpp:9
UNCOVERED_FUNC: in Uncovered2()
MODULE_WITH_COVERAGE: /pathto/LLVMFuzzer-DSOTest
UNCOVERED_LINE: in LLVMFuzzerTestOneInput /pathto/DSOTestMain.cpp:21
UNCOVERED_LINE: in LLVMFuzzerTestOneInput /pathto/DSOTestMain.cpp:27
UNCOVERED_FILE: /pathto/DSOTestExtra.cpp

Several things are not perfect here:
* we are using objdump+awk instead of sancov because sancov does not support DSOs yet.
* this breaks in the presence of ASAN_OPTIONS=strip_path_prefix=...
  (need to implement another API to get the module name by PC)

llvm-svn: 284554
2016-10-19 00:12:03 +00:00
Kostya Serebryany bb59ef77ca [libFuzzer] detect leaks after every run when executing fixed inputs (./fuzzer -runs=1000000 my-file)
llvm-svn: 284514
2016-10-18 18:38:08 +00:00
Kostya Serebryany 8dfed45cd4 [libFuzzer] reshuffle the code for -exit_on_src_pos and -exit_on_item
llvm-svn: 284508
2016-10-18 18:06:05 +00:00
Kostya Serebryany 9a4b10a56f [libFuzzer] swap bytes in integers when handling CMP traces
llvm-svn: 284301
2016-10-15 04:00:07 +00:00
Kostya Serebryany f9b8e8b117 [libFuzzer] better algorithm for -minimize_crash
llvm-svn: 284299
2016-10-15 01:00:24 +00:00
Kostya Serebryany e450e40741 [libFuzzer] remove subdir fuzzer-test-suite as it is now superseded with https://github.com/google/fuzzer-test-suite
llvm-svn: 284275
2016-10-14 20:26:40 +00:00
Kostya Serebryany a5f94fb6c9 [libFuzzer] add -trace_cmp=1 (guiding mutations based on the observed CMP instructions). This is a reincarnation of the previously deleted -use_traces, but using a different approach for collecting traces. Still a toy, but at least it scales well. Also fix -merge in trace-pc-guard mode
llvm-svn: 284273
2016-10-14 20:20:33 +00:00
Kostya Serebryany 0381374f96 [libFuzzer] more detailed message for disabled leak detection
llvm-svn: 284169
2016-10-13 22:24:10 +00:00
Kostya Serebryany a17d23eaa7 [libFuzzer] add -trace_malloc= flag
llvm-svn: 284149
2016-10-13 19:06:46 +00:00
Kostya Serebryany 17d176e16b [libFuzzer] reapply r283946: refactoring to speed things up, NFC. Now with a fix for gcc build
llvm-svn: 284132
2016-10-13 16:19:09 +00:00
Daniel Jasper 90d990e034 Revert "[libFuzzer] refactoring to speed things up, NFC"
This reverts commit r283946.

This breaks when build with GCC:
lib/Fuzzer/FuzzerTracePC.cpp:169:6: error: always_inline function might not be inlinable [-Werror=attributes]
lib/Fuzzer/FuzzerTracePC.cpp:169:6: error: inlining failed in call to always_inline 'void fuzzer::TracePC::HandleCmp(void*, T, T) [with T = long unsigned int]': target specific option mismatch
lib/Fuzzer/FuzzerTracePC.cpp:198:65: error: called from here

llvm-svn: 283979
2016-10-12 07:26:46 +00:00
Kostya Serebryany a09d11e108 [libFuzzer] refactoring to speed things up, NFC
llvm-svn: 283946
2016-10-11 21:27:37 +00:00
Kostya Serebryany d19919a80e [libFuzzer] implement value profile for switch, increase the size of the PCs array, make sure we don't overflow it
llvm-svn: 283841
2016-10-11 01:14:41 +00:00
Kostya Serebryany 3e0e901a18 [libFuzzer] add switch tests
llvm-svn: 283840
2016-10-11 01:13:32 +00:00
Kostya Serebryany 7abb95d3b3 [libFuzzer] make a test less flaky
llvm-svn: 283686
2016-10-09 03:45:38 +00:00
Kostya Serebryany c5325ed29d [libFuzzer] when shrinking the corpus, delete evicted files previously created by the current process
llvm-svn: 283682
2016-10-08 23:24:45 +00:00
Kostya Serebryany 9adc7c8b4a [libFuzzer] control the reload interval by a flag, make it 10 seconds by default
llvm-svn: 283676
2016-10-08 22:12:14 +00:00
Kostya Serebryany cd04ec25dd [libFuzzer] fix use-after-free in libFuzzer found by ... fuzzing.
llvm-svn: 283675
2016-10-08 21:57:48 +00:00
Kostya Serebryany 936b1e774f [libFuzzer] be more careful with memory usage, print peak rss in status lines
llvm-svn: 283418
2016-10-06 05:14:00 +00:00
Kostya Serebryany 3b564e9765 [libFuzzer] when re-running for lsan, don't look at the coverage
llvm-svn: 283411
2016-10-05 23:31:01 +00:00
Kostya Serebryany 1c73f1bf27 [libFuzzer] refactoring to make -shrink=1 work for value profile, added a test.
llvm-svn: 283409
2016-10-05 22:56:21 +00:00
Kostya Serebryany 379359c53a [libFuzzer] add ShrinkValueProfileTest, move code around, NFC
llvm-svn: 283286
2016-10-05 01:09:40 +00:00
Kostya Serebryany 2455f0d013 [libFuzzer] clear the corpus elements if they are evicted (i.e. smaller elements with proper coverage are found). Make sure we never try to mutate empty element. Print the corpus size in bytes in the status lines
llvm-svn: 283279
2016-10-05 00:25:17 +00:00
Kostya Serebryany 4820cc988f [libFuzzer] remove dfsan support and some related stale code. This is not being used and as is is pretty weak anyway
llvm-svn: 283187
2016-10-04 06:08:46 +00:00
Kostya Serebryany 5a52a11ce4 [libFuzzer] change the probabilities so that we choose only the inputs that are known to be minimal inputs for at least one coverage feature (works only with -shrink=1 for now)
llvm-svn: 283178
2016-10-04 01:51:44 +00:00
Kostya Serebryany a5f1adab56 [libFuzzer] add fuzzer test for libxml2, finds https://bugzilla.gnome.org/show_bug.cgi?id=751631
llvm-svn: 283024
2016-10-01 07:37:40 +00:00
Kostya Serebryany d1f31d0a49 [libFuzzer] fix a recent bugs (buffer overflow)
llvm-svn: 283021
2016-10-01 07:13:25 +00:00
Kostya Serebryany d216922a80 [libFuzzer] implement the -shrink=1 option that tires to make elements of the corpus smaller, off by default
llvm-svn: 282995
2016-10-01 01:04:29 +00:00
Kostya Serebryany 90f8f36bca [libFuzzer] remove some experimental code
llvm-svn: 282983
2016-09-30 23:29:27 +00:00
Kostya Serebryany 7022b94687 [libFuzzer] fix openssl fuzzer tests when running on a machine w/o openssl installed
llvm-svn: 282972
2016-09-30 22:35:08 +00:00
Kostya Serebryany e7e790bad6 [libFuzzer] remove unused option
llvm-svn: 282971
2016-09-30 22:29:57 +00:00
Kostya Serebryany b7e7a5473d [libFuzzer] move common parts of shell scripts into a separate file
llvm-svn: 282954
2016-09-30 21:12:30 +00:00
Kostya Serebryany cfa31b6307 [libFuzzer] add a fuzzer test that finds CVE-2015-3193
llvm-svn: 282892
2016-09-30 18:16:16 +00:00
Kostya Serebryany cad612a472 [libfuzzer] test for c-ares CVE-2016-5180
llvm-svn: 282839
2016-09-30 05:15:45 +00:00
Kostya Serebryany b3949ef885 [libFuzzer] remove the code for -print_pcs=1 with the old coverage. It still works with the new one (trace-pc-guard)
llvm-svn: 282831
2016-09-30 01:24:57 +00:00
Kostya Serebryany 2c55613a08 [libFuzzer] more the feature set to InputCorpus; on feature update, change the feature counter of the old best input
llvm-svn: 282829
2016-09-30 01:19:56 +00:00
Kostya Serebryany a9b0dd0e51 [sanitizer-coverage/libFuzzer] make the guards for trace-pc 32-bit; create one array of guards per function, instead of one guard per BB. reorganize the code so that trace-pc-guard does not create unneeded globals
llvm-svn: 282735
2016-09-29 17:43:24 +00:00
Kostya Serebryany a9a135b4f5 [libFuzzer] initialize ValueBitMap::NumBits
llvm-svn: 282721
2016-09-29 15:51:28 +00:00
Kostya Serebryany 3ee6c213d6 [libFuzzer] speedup TracePC::FinalizeTrace
llvm-svn: 282562
2016-09-28 01:16:24 +00:00
Kostya Serebryany 7d6935c184 [libFuzzer] run re2 test in 8 threads by default
llvm-svn: 282469
2016-09-27 03:33:57 +00:00
Kostya Serebryany 45c144754b [sanitizer-coverage] fix a bug in trace-gep
llvm-svn: 282467
2016-09-27 01:55:08 +00:00
Kostya Serebryany 53543af036 [libFuzzer] add a test based on openssl-1.0.1f (finds heartbleed)
llvm-svn: 282460
2016-09-27 00:27:40 +00:00
Kostya Serebryany 5ff481fd9e [libFuzzer] add -exit_on_src_pos to test libFuzzer itself, add a test script for RE2 that uses this flag
llvm-svn: 282458
2016-09-27 00:10:20 +00:00
Kostya Serebryany 273d767215 [libFuzzer] add a standalone build script
llvm-svn: 282321
2016-09-24 04:00:00 +00:00
Kostya Serebryany 0800b81a21 [libFuzzer] simplify HandleTrace again, start re-running interesting units and collecting their features.
llvm-svn: 282316
2016-09-23 23:51:58 +00:00
Kostya Serebryany 2d1d944f7e [libFuzzer] first steps in adding a proper automated test suite based on real-life code: add a script to build RE2 at a revision that has known bugs
llvm-svn: 282292
2016-09-23 20:43:22 +00:00
Kostya Serebryany 0d26de3922 [libFuzzer] reset Counters (trace-pc-guard) before every run
llvm-svn: 282284
2016-09-23 20:04:13 +00:00
Kostya Serebryany ce1cab169f [libFuzzer] be more precise about what we reset in TracePC
llvm-svn: 282225
2016-09-23 02:18:59 +00:00
Kostya Serebryany 16a145fd0f [libFuzzer] fix merging with trace-pc-guard
llvm-svn: 282224
2016-09-23 01:58:51 +00:00
Kostya Serebryany 87a598e19f [libFuzzer] simplify the TracePC logic
llvm-svn: 282222
2016-09-23 01:20:07 +00:00
Kostya Serebryany ab73c6924f [libFuzzer] move value profiling logic into TracePC
llvm-svn: 282219
2016-09-23 00:46:18 +00:00
Kostya Serebryany d28099de5d [libFuzzer] change ValueBitMap to remember the number of bits in it
llvm-svn: 282216
2016-09-23 00:22:46 +00:00
Kostya Serebryany be0ed59cdc [libFuzzer] simplify the crash minimizer; split MaxLen into two: MaxInputLen and MaxMutationLen, allow MaxMutationLen to be less than MaxInputLen
llvm-svn: 282211
2016-09-22 23:16:36 +00:00
Kostya Serebryany 624f59f4d8 [libFuzzer] add 'features' to the corpus elements, allow mutations with Size > MaxSize, fix sha1 in corpus stats; various refactorings
llvm-svn: 282129
2016-09-22 01:34:58 +00:00
Kostya Serebryany c9e3de35ed [libFuzzer] one more test
llvm-svn: 282127
2016-09-22 00:57:29 +00:00
Kostya Serebryany 29bb664075 [libFuzzer] add stats to the corpus; more refactoring
llvm-svn: 282121
2016-09-21 22:42:17 +00:00
Kostya Serebryany 20801e1b8a [libFuzzer] more refactoring; don't compute sha1sum every time we mutate a unit from the corpus, use the stored one.
llvm-svn: 282115
2016-09-21 21:41:48 +00:00
Kostya Serebryany 8658618ea0 [libFuzzer] more refactoring
llvm-svn: 282113
2016-09-21 21:17:23 +00:00
Kostya Serebryany 225d8e45d4 [libFuzzer] fix libc++ build
llvm-svn: 282050
2016-09-21 03:50:37 +00:00
Kostya Serebryany 556894fb10 [libFuzzer] more refactoring; NFC
llvm-svn: 282047
2016-09-21 02:05:39 +00:00
Kostya Serebryany 6f5a804cdb [libFuzzer] refactoring: split the large header into many; NFC
llvm-svn: 282044
2016-09-21 01:50:50 +00:00
Kostya Serebryany 09aa01a6f8 [libFuzzer] refactoring: move the Corpus into a separate class; delete two unused experimental features
llvm-svn: 282042
2016-09-21 01:04:43 +00:00
Kostya Serebryany 3750c04f7e [libFuzzer] use sleep() instead of std::this_thread::sleep_for to avoid coverage from instrumented libc++
llvm-svn: 281933
2016-09-19 20:32:34 +00:00
Kostya Serebryany b706b481ba [libFuzzer] add -print_coverage=1 flag to print coverage directly from libFuzzer
llvm-svn: 281866
2016-09-18 21:47:08 +00:00
Kostya Serebryany 8e781a888a [libFuzzer] use 'if guard' instead of 'if guard >= 0' with trace-pc; change the guard type to intptr_t; use separate array for 8-bit counters
llvm-svn: 281845
2016-09-18 04:52:23 +00:00
Kostya Serebryany bc3789a919 [libFuzzer] properly reset the guards when reseting the coverage. Also try to fix check-fuzzer on the bot
llvm-svn: 281814
2016-09-17 06:01:55 +00:00
Kostya Serebryany 3e36ec1d18 [libFuzzer] change trace-pc to use 8-byte guards
llvm-svn: 281810
2016-09-17 05:04:47 +00:00
Kostya Serebryany 0984517021 [libFuzzer] make caller-callee feedback work with trace-pc-guard
llvm-svn: 281667
2016-09-15 22:16:15 +00:00
Kostya Serebryany 21c3573733 [libFuzzer] fix the build for AFLDriverTest
llvm-svn: 281633
2016-09-15 18:10:38 +00:00
Kostya Serebryany 09e416615e [libFuzzer] disable test that requires debug info -- it fails on the bot
llvm-svn: 281584
2016-09-15 05:46:58 +00:00
Kostya Serebryany 0b47fbcb30 [libFuzzer] move the AFL driver build rule test into the uninstrumented dir
llvm-svn: 281583
2016-09-15 05:17:39 +00:00
Kostya Serebryany 33a497abf4 [libFuzzer] fix print_pcs test
llvm-svn: 281580
2016-09-15 04:43:06 +00:00
Kostya Serebryany 5350178487 [libFuzzer] implement print_pcs with trace-pc-guard. Change the trace-pc-guard heuristic for 8-bit counters to look more like in AFL (not that it's provable better, but the existin test preferes this heuristic)
llvm-svn: 281577
2016-09-15 04:36:45 +00:00
Kostya Serebryany a5277d59d0 [libFuzzer] add 8-bit counters to trace-pc-guard handler
llvm-svn: 281568
2016-09-15 01:30:18 +00:00
Kostya Serebryany a00b243c75 [libFuzzer] start using trace-pc-guard as an alternative source of coverage
llvm-svn: 281435
2016-09-14 02:13:06 +00:00
Kostya Serebryany 8c537c556a [libFuzzer] print a failed-merge warning only in the merge mode
llvm-svn: 281130
2016-09-10 02:17:22 +00:00
Kostya Serebryany 4529960a3b [libFuzzer] don't print help for internal flags
llvm-svn: 281124
2016-09-10 00:35:30 +00:00
Kostya Serebryany b991cc1f0e [libFuzzer] print a visible message if merge fails due to a crash
llvm-svn: 281122
2016-09-10 00:15:41 +00:00
Kostya Serebryany 1837152a34 [libFuzzer] use sizeof() in tests instead of 4 and 8
llvm-svn: 281111
2016-09-09 22:21:16 +00:00
Kostya Serebryany 4b17a331ae [libFuzzer] one more puzzle for value profile
llvm-svn: 281106
2016-09-09 21:58:42 +00:00
Kostya Serebryany 00ef27112e [libFuzzer] one more puzzle, value_profile cracks it in a second
llvm-svn: 281066
2016-09-09 18:00:04 +00:00
Kostya Serebryany b76a2a5503 [libFuzzer] improve -print_pcs to not print new PCs coming from libFuzzer itself
llvm-svn: 281016
2016-09-09 02:38:28 +00:00
Kostya Serebryany 8ea4f9873b [libFuzzer] remove unneeded call
llvm-svn: 281014
2016-09-09 01:57:38 +00:00
Kostya Serebryany 5c04bd250e [libFuzzer] remove use_traces=1 since use_value_profile seems to be strictly better
llvm-svn: 281007
2016-09-09 01:17:03 +00:00
Kostya Serebryany e2d0f63654 [libFuzzer] add -minimize_crash flag (to minimize crashers). also add two tests that I failed to commit last time
llvm-svn: 280332
2016-09-01 01:22:27 +00:00
Mike Aizatsky b077d3fef2 [libfuzzer] simplified unit truncation; do not write trunc items to disc
Differential Revision: https://reviews.llvm.org/D24049

llvm-svn: 280153
2016-08-30 20:49:07 +00:00
Kostya Serebryany a016a45d60 [libFuzzer] fix a bug when running a single unit of N bytes with -max_len=M, M<N, caused a buffer overflow
llvm-svn: 280098
2016-08-30 14:52:05 +00:00
Kostya Serebryany 248d11519a [libFuzzer] stop using bits for memcmp's value profile -- seems to blow up the corpus too much
llvm-svn: 280096
2016-08-30 14:39:33 +00:00
Kostya Serebryany d4492f8101 [libFuzzer] use bits instead of bytes for memcmp/strcmp value profile -- the fuzzer reaches the goal much faster, at least on the simple puzzles
llvm-svn: 280054
2016-08-30 03:05:50 +00:00
Kostya Serebryany 4d22e4fcb9 [libFuzzer] use trace-div and trace-gep for guided fuzzing, add tests
llvm-svn: 280046
2016-08-30 01:30:14 +00:00
Kostya Serebryany 3e5991e540 [libFuzzer] simplify a test to make it pass on the bot
llvm-svn: 279796
2016-08-26 00:18:16 +00:00
Kostya Serebryany 1426f59a76 [libFuzzer] make sure we have symbols on fuzzer tests
llvm-svn: 279792
2016-08-25 23:30:02 +00:00
Kostya Serebryany 0f0fa4faf2 [libFizzer] rename -print_new_cov_pcs=1 into -print_pcs=1 and make it more useful: print PCs only after the initial corpus has been read and symbolize them
llvm-svn: 279787
2016-08-25 22:35:08 +00:00
Kostya Serebryany f67357c671 [libFuzzer] simplify the code, NFC
llvm-svn: 279697
2016-08-25 01:25:03 +00:00
Kostya Serebryany 41bcb830af [libFuzzer] make a test more deterministic
llvm-svn: 279686
2016-08-24 23:10:17 +00:00
Kostya Serebryany bceadcf1cd [libFuzzer] use __attribute__((target("popcnt"))) only on x86_64
llvm-svn: 279601
2016-08-24 01:38:42 +00:00
Kostya Serebryany ac524cfcce [libFuzzer] collect 64 states for value profile, not 65
llvm-svn: 279588
2016-08-23 23:37:37 +00:00
Kostya Serebryany a533e514b8 [libFuzzer] fix the non-debug build warnings
llvm-svn: 279321
2016-08-19 20:57:09 +00:00
Kostya Serebryany 32661f9d66 [libFuzzer] add more __attribute__((visibility("default")))
llvm-svn: 279143
2016-08-18 20:52:52 +00:00
Kostya Serebryany 524c3f32e7 [sanitizer-coverage/libFuzzer] instrument comparisons with __sanitizer_cov_trace_cmp[1248] instead of __sanitizer_cov_trace_cmp, don't pass the comparison type to save a bit performance. Use these new callbacks in libFuzzer
llvm-svn: 279027
2016-08-18 01:25:28 +00:00
Kostya Serebryany 5a5d5548f0 [libFuzzer] force proper popcnt instruction
llvm-svn: 279002
2016-08-17 23:09:57 +00:00
Kostya Serebryany e72774dd69 [libFuzzer] given 0 and 255 more preference when inserting repeated bytes
llvm-svn: 278986
2016-08-17 21:50:54 +00:00
Kostya Serebryany 0c537b124c [libFuzzer] one more mutation: ChangeBinaryInteger; also fix the breakage from r278970
llvm-svn: 278982
2016-08-17 21:30:30 +00:00
Kostya Serebryany a9a548049a [libFuzzer] when printing the reproducer input, also print the base input and the mutation sequence
llvm-svn: 278975
2016-08-17 20:45:23 +00:00
Justin Bogner cd1d5aaf2e Replace a few more "fall through" comments with LLVM_FALLTHROUGH
Follow up to r278902. I had missed "fall through", with a space.

llvm-svn: 278970
2016-08-17 20:30:52 +00:00
Kostya Serebryany a7398ba024 [libFuzzer] more mutations
llvm-svn: 278950
2016-08-17 18:10:42 +00:00
Kostya Serebryany 3044390af1 [libFuzzer] minor speed improvement
llvm-svn: 278856
2016-08-16 21:28:05 +00:00
Kostya Serebryany d46a59fac4 [libFuzzer] new experimental feature: value profiling. Profiles values that affect control flow and treats new values as new coverage.
llvm-svn: 278839
2016-08-16 19:33:51 +00:00
Kostya Serebryany c98ef718ea [libFuzzer] refactoring around PCMap, NFC
llvm-svn: 278825
2016-08-16 17:37:13 +00:00
Kostya Serebryany bdb220c7a0 [libFuzzer] print a verbose message after executing inputs in non-fuzzing mode
llvm-svn: 278724
2016-08-15 19:44:04 +00:00
Kostya Serebryany a0d40a21e7 [libFuzzer] fix the bot
llvm-svn: 278721
2016-08-15 19:36:13 +00:00
Kostya Serebryany dfbe59b03d [libFuzzer] add InsertRepeatedBytes and EraseBytes.
New mutation: InsertRepeatedBytes.
Updated mutation: EraseByte => EraseBytes.

This helps https://github.com/google/sanitizers/issues/710
where libFuzzer was not able to find a known bug.
Now it finds it in minutes.

Hopefully, the change is general enough to help other targets.

llvm-svn: 278687
2016-08-15 17:48:28 +00:00
Dan Liew ed3c9cae49 [LibFuzzer] Fix `-jobs=<N>` where <N> > 1 and the number of workers is > 1 on macOS.
The original `ExecuteCommand()` called `system()` from the C library.
The C library implementation of this on macOS contains a mutex which
serializes calls to `system()`. This prevented the `-jobs=` flag
from running copies of the fuzzing binary in parallel which is
the opposite of what is intended.

To fix this on macOS an alternative implementation of `ExecuteCommand()`
is provided that can be used concurrently. This is provided in
`FuzzerUtilDarwin.cpp` which is guarded to only compile code on Apple
platforms. The existing implementation has been moved to a new file
`FuzzerUtilLinux.cpp` which is guarded to only compile code on Linux.

This commit includes a simple test to check that LibFuzzer is being
executed in parallel when requested.

Differential Revision: https://reviews.llvm.org/D22742

llvm-svn: 278544
2016-08-12 18:29:36 +00:00
Kostya Serebryany 728447bd3b [libFuzzer] make libFuzzer work with a bit older clang versions
llvm-svn: 277941
2016-08-06 21:28:56 +00:00
Kostya Serebryany ff1f2107ec [libFuzzer] don't print bogus error message
llvm-svn: 277940
2016-08-06 21:23:29 +00:00
Mike Aizatsky a8e84b9b37 [libfuzzer] do not warn about missing pcbuffer functions: they are new.
llvm-svn: 277927
2016-08-06 17:03:22 +00:00
Mike Aizatsky b4bbc3bb7a [sanitizers] trace buffer API to use user-allocated buffer.
Differential Revision: https://reviews.llvm.org/D23185

llvm-svn: 277859
2016-08-05 20:09:53 +00:00
Kostya Serebryany 0ccf06f467 [libFuzzer] extend the messages printed by afl_driver
llvm-svn: 276052
2016-07-19 23:18:28 +00:00
Kostya Serebryany 6b08be9279 [libFuzzer] properly intercept memmem
llvm-svn: 276006
2016-07-19 18:29:06 +00:00
Kostya Serebryany c135b55ae0 [libFuzzer] add hooks for strstr, strcasestr, strcasecmp, strncasecmp
llvm-svn: 275648
2016-07-15 23:27:19 +00:00
Kostya Serebryany 5d9a17742e [libFuzzer] add ThreadedLeakTest
llvm-svn: 275582
2016-07-15 17:19:43 +00:00
Dan Liew 30ca81f1f7 [LibFuzzer] Unbreak the build on macOS which was broken by r272858.
``afl_driver.cpp`` currently relies on weak symbols which doesn't
work properly under macOS. For now fix the build by providing a
dummy implementation of ``LLVMFuzzerInitialize(...)``. This is just
a temporary measure until we fix ``afl_driver.cpp`` for macOS.

llvm-svn: 274778
2016-07-07 18:14:11 +00:00
Mike Aizatsky 8ba86a5a48 [libFuzzer] Let user specify extra stats file.
Summary: If AFL_DRIVER_EXTRA_STATS_FILENAME is set and valid, write to it peak_rss_mb and slowest_unit_time_sec. These are both stats that libFuzzer can print but afl cannot.

Reviewers: kcc, aizatsky, metzman

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D21742

llvm-svn: 274273
2016-06-30 20:43:06 +00:00
Mike Aizatsky f0b3e85f4e [libfuzzer] moving is_ascii handler inside mutation dispatcher.
Summary: It also fixes a bug, when first random might not be ascii.

Differential Revision: http://reviews.llvm.org/D21573

llvm-svn: 273611
2016-06-23 20:44:48 +00:00
Vitaly Buka 0618cbacb6 [libFuzzer] Add standard license info and comment header to AFLDriverTest.cpp
Summary: Add license info and brief description of file to AFLDriverTest.cpp.

Reviewers: kcc, aizatsky

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D21487

llvm-svn: 273527
2016-06-23 02:19:36 +00:00
Kostya Serebryany 042d1a7b04 [libFuzzer] make the single-run output more reliable
llvm-svn: 272998
2016-06-17 13:07:06 +00:00
Kostya Serebryany fd6ad5bba9 [libFuzzer] use the new chainable malloc hooks instead of the old un-chainable ones, use atomic for malloc/free counters instead of a thread local counter in the main thread. This should make on-the-spot leak detection in libFuzzer more reliable
llvm-svn: 272948
2016-06-16 20:17:41 +00:00
Vitaly Buka 7bd4720e6b Fix test from D21194
Bot sets ASAN_OPTIONS=handle_abort=1 which prevents expected crash.

llvm-svn: 272866
2016-06-16 01:52:48 +00:00
Vitaly Buka d6da8f6612 Debugging D21194 issues on bot
llvm-svn: 272863
2016-06-16 01:26:46 +00:00
Vitaly Buka d01720d46d Enable libFuzzer's afl_driver to append stderr to a file.
Summary:
[libFuzzer] Enable afl_driver to append stderr to a user specified file.

Append stderr of afl_driver to the file specified by the environmental variable
AFL_DRIVER_STDERR_DUPLICATE_FILENAME if it is set. This lets users see outputs
on crashes without rerunning crashing test cases (which won't work for crashes
that are difficult to reproduce). Before this patch, stderr would only be sent to afl-fuzz
and users would have no way of seeing it.

Reviewers: llvm-commits, aizatsky, kcc, vitalybuka

Subscribers: vitalybuka

Differential Revision: http://reviews.llvm.org/D21194

llvm-svn: 272858
2016-06-16 00:14:42 +00:00
Dan Liew c4989d27b5 [LibFuzzer] Fix ``FuzzerMutate.ShuffleBytes2`` unit test on OSX.
The ``FuzzerMutate.ShuffleBytes2`` unit test was failing on
OSX due to the implementation of ``std::random_shuffle()``
being different between libcxx and libstdc++.

@kcc has decided (see http://reviews.llvm.org/D21218) it is acceptable
for there to be different mutation behavior on different platforms so
this commit just adjusts the test to perform the minimum number of
iterations (that is a power of 2) to see all the mutations the unit test
is looking for.

Differential Revision: http://reviews.llvm.org/D21359

llvm-svn: 272743
2016-06-15 01:40:02 +00:00
Vitaly Buka dca553d021 Revert "Enable libFuzzer's afl_driver to append stderr to a file."
Crashes with AddressSanitizer: SEGV on unknown address
http://lab.llvm.org:8011/builders/sanitizer-x86_64-linux-fuzzer/builds/9924/steps/annotate/logs/stdio

This reverts commit r272706.

llvm-svn: 272726
2016-06-14 22:09:00 +00:00
Vitaly Buka 4b73cc88bf Enable libFuzzer's afl_driver to append stderr to a file.
Summary:
[libFuzzer] Enable afl_driver to append stderr to a user specified file.

Append stderr of afl_driver to the file specified by the environmental variable
AFL_DRIVER_STDERR_DUPLICATE_FILENAME if it is set. This lets users see outputs
on crashes without rerunning crashing test cases (which won't work for crashes
that are difficult to reproduce). Before this patch, stderr would only be sent to afl-fuzz
and users would have no way of seeing it.

Reviewers: llvm-commits, aizatsky, kcc, vitalybuka

Subscribers: vitalybuka

Differential Revision: http://reviews.llvm.org/D21194

llvm-svn: 272706
2016-06-14 20:42:05 +00:00
Dan Liew 916bc2b024 [LibFuzzer] Disable the ``fuzzer-trace-pc.test`` test on non-linux platforms.
On OSX this test sometimes fails due to the
``LLVMFuzzer-FullCoverageSetTest-TracePC`` program going over the
default 2GiB memory limit. This shouldn't be happening and needs
investigating. For now just disable the test so we can set up an
OSX buildbot.

Differential Revision: http://reviews.llvm.org/D21319

llvm-svn: 272696
2016-06-14 19:15:13 +00:00
Dan Liew 02432480c7 [LibFuzzer] Move tests in ``fuzzer-traces.test`` that require hooks to their own test.
The tests in ``fuzzer-traces-hooks.test`` only work on Linux because calls to hooks
(e.g. ``__sanitizer_weak_hook_memcmp()``) from inside the sanitizer
runtime are only implemented on Linux. Therefore these tests are set to
only run on Linux.

Differential Revision: http://reviews.llvm.org/D21253

llvm-svn: 272600
2016-06-14 00:11:34 +00:00
Dan Liew 0617f15897 [LibFuzzer] Fix some unit test crashes on OSX.
This fixes the following unit tests:

FuzzerDictionary.ParseOneDictionaryEntry
FuzzerDictionary.ParseDictionaryFile

The issue appears to be mixing non-ASan-ified code (LibFuzzer) and
ASan-ified code (the unittest) as the tests would pass fine if
everything was built with ASan enabled.

I believe the issue is that different implementations of std::vector<>
are being used in LibFuzzer and outside LibFuzzer (in the unittests).
For Libcxx (I've not seen the issue manifest for libstdc++) we can disable
the ASanified std::vector<> by definining the ``_LIBCPP_HAS_NO_ASAN`` macro.
Doing this fixes the tests on OSX.

Differential Revision: http://reviews.llvm.org/D21049

llvm-svn: 272374
2016-06-10 05:33:07 +00:00
Kostya Serebryany f7798526b9 [libFuzzer] add one more OOM test, which we currently don't handle very well
llvm-svn: 272240
2016-06-09 01:20:35 +00:00
Kostya Serebryany 53b7b3ca5f [libFuzzer] add 'weak' back to __sanitizer_malloc_hook and __sanitizer_free_hook
llvm-svn: 272116
2016-06-08 04:49:29 +00:00
Kostya Serebryany 76f425211e [libFuzzer] add a test that is built w/o coverage instrumentation but has the coverage rt (it should now fail with a descriptive message)
llvm-svn: 272090
2016-06-08 01:46:13 +00:00
Dan Liew 1873a496e2 [LibFuzzer] Declare and use sanitizer functions in ``fuzzer::ExternalFunctions``
This fixes linking problems on OSX.

Unfortunately it turns out we need to use an instance of the
``fuzzer::ExternalFunctions`` object in several places so this
commit also replaces all instances with a single global instance.

It also turns out initializing a global ``fuzzer::ExternalFunctions``
before main is entered (i.e. letting the object be initialised by the
global initializers) is not safe (on OSX the call to ``Printf()`` in the
CTOR crashes if it is called from a global initializer) so we instead
have a global ``fuzzer::ExternalFunctions*`` and initialize it inside
``FuzzerDriver()``.

Multiple unit tests depend also depend on the
``fuzzer::ExternalFunctions*`` global so a ``main()`` function has been
added that initializes it before running any tests.

Differential Revision: http://reviews.llvm.org/D20943

llvm-svn: 272072
2016-06-07 23:32:50 +00:00