teak-llvm/compiler-rt/lib/sanitizer_common/sanitizer_flags.cpp
Dan Liew 4c39f34199 [SanitizerCommon] Print the current value of options when printing out help.
Summary:
Previously it wasn't obvious what the default value of various sanitizer
options were. A very close approximation of the "default values" for the
options are the current value of the options at the time of printing the
help output.

In the case that no other options are provided then the current values
are the default values (apart from `help`).

```
ASAN_OPTIONS=help=1 ./program
```

This patch causes the current option values to be printed when the
`help` output is enabled. The original intention for this patch was to append
`(Default: <value>)` to an option's help text. However because this
is technically wrong (and misleading) I've opted to append
`(Current Value: <value>)` instead.

When trying to implement a way of displaying the default value of the
options I tried another solution where the default value used in `*.inc` files
were used to create compile time strings that where used when printing
the help output. This solution was not satisfactory for several reasons:

* Stringifying the default values with the preprocessor did not work very
well in several cases.  Some options contain boolean operators which no
amount of macro expansion can get rid of.
* It was much more invasive than this patch. Every sanitizer had to be changed.
* The settings of `__<sanitizer>_default_options()` are ignored.

For those reasons I opted for the solution in this patch.

rdar://problem/42567204

Reviewers: kubamracek, yln, kcc, dvyukov, vitalybuka, cryptoad, eugenis, samsonov

Subscribers: #sanitizers, llvm-commits

Tags: #sanitizers, #llvm

Differential Revision: https://reviews.llvm.org/D69546
2019-11-14 14:04:34 -08:00

130 lines
3.9 KiB
C++

//===-- sanitizer_flags.cpp -----------------------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file is a part of ThreadSanitizer/AddressSanitizer runtime.
//
//===----------------------------------------------------------------------===//
#include "sanitizer_flags.h"
#include "sanitizer_common.h"
#include "sanitizer_libc.h"
#include "sanitizer_list.h"
#include "sanitizer_flag_parser.h"
namespace __sanitizer {
CommonFlags common_flags_dont_use;
void CommonFlags::SetDefaults() {
#define COMMON_FLAG(Type, Name, DefaultValue, Description) Name = DefaultValue;
#include "sanitizer_flags.inc"
#undef COMMON_FLAG
}
void CommonFlags::CopyFrom(const CommonFlags &other) {
internal_memcpy(this, &other, sizeof(*this));
}
// Copy the string from "s" to "out", making the following substitutions:
// %b = binary basename
// %p = pid
void SubstituteForFlagValue(const char *s, char *out, uptr out_size) {
char *out_end = out + out_size;
while (*s && out < out_end - 1) {
if (s[0] != '%') {
*out++ = *s++;
continue;
}
switch (s[1]) {
case 'b': {
const char *base = GetProcessName();
CHECK(base);
while (*base && out < out_end - 1)
*out++ = *base++;
s += 2; // skip "%b"
break;
}
case 'p': {
int pid = internal_getpid();
char buf[32];
char *buf_pos = buf + 32;
do {
*--buf_pos = (pid % 10) + '0';
pid /= 10;
} while (pid);
while (buf_pos < buf + 32 && out < out_end - 1)
*out++ = *buf_pos++;
s += 2; // skip "%p"
break;
}
default:
*out++ = *s++;
break;
}
}
CHECK(out < out_end - 1);
*out = '\0';
}
class FlagHandlerInclude : public FlagHandlerBase {
FlagParser *parser_;
bool ignore_missing_;
const char *original_path_;
public:
explicit FlagHandlerInclude(FlagParser *parser, bool ignore_missing)
: parser_(parser), ignore_missing_(ignore_missing), original_path_("") {}
bool Parse(const char *value) final {
original_path_ = value;
if (internal_strchr(value, '%')) {
char *buf = (char *)MmapOrDie(kMaxPathLength, "FlagHandlerInclude");
SubstituteForFlagValue(value, buf, kMaxPathLength);
bool res = parser_->ParseFile(buf, ignore_missing_);
UnmapOrDie(buf, kMaxPathLength);
return res;
}
return parser_->ParseFile(value, ignore_missing_);
}
bool Format(char *buffer, uptr size) {
// Note `original_path_` isn't actually what's parsed due to `%`
// substitutions. Printing the substituted path would require holding onto
// mmap'ed memory.
return FormatString(buffer, size, original_path_);
}
};
void RegisterIncludeFlags(FlagParser *parser, CommonFlags *cf) {
FlagHandlerInclude *fh_include = new (FlagParser::Alloc)
FlagHandlerInclude(parser, /*ignore_missing*/ false);
parser->RegisterHandler("include", fh_include,
"read more options from the given file");
FlagHandlerInclude *fh_include_if_exists = new (FlagParser::Alloc)
FlagHandlerInclude(parser, /*ignore_missing*/ true);
parser->RegisterHandler(
"include_if_exists", fh_include_if_exists,
"read more options from the given file (if it exists)");
}
void RegisterCommonFlags(FlagParser *parser, CommonFlags *cf) {
#define COMMON_FLAG(Type, Name, DefaultValue, Description) \
RegisterFlag(parser, #Name, Description, &cf->Name);
#include "sanitizer_flags.inc"
#undef COMMON_FLAG
RegisterIncludeFlags(parser, cf);
}
void InitializeCommonFlags(CommonFlags *cf) {
// need to record coverage to generate coverage report.
cf->coverage |= cf->html_cov_report;
SetVerbosity(cf->verbosity);
}
} // namespace __sanitizer