compiler-rt/lib/xray/xray_flags.cpp

   1 //===-- xray_flags.cpp ------------------------------------------*- C++ -*-===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8 //
   9 // This file is a part of XRay, a dynamic runtime instrumentation system.
  10 //
  11 // XRay flag parsing logic.
  12 //===----------------------------------------------------------------------===//
  13
  14 #include "xray_flags.h"
  15 #include "sanitizer_common/sanitizer_common.h"
  16 #include "sanitizer_common/sanitizer_flag_parser.h"
  17 #include "sanitizer_common/sanitizer_libc.h"
  18 #include "xray_defs.h"
  19
  20 using namespace __sanitizer;
  21
  22 namespace __xray {
  23
  24 Flags xray_flags_dont_use_directly; // use via flags().
  25
  26 void Flags::setDefaults() XRAY_NEVER_INSTRUMENT {
  27 #define XRAY_FLAG(Type, Name, DefaultValue, Description) Name = DefaultValue;
  28 #include "xray_flags.inc"
  29 #undef XRAY_FLAG
  30 }
  31
  32 void registerXRayFlags(FlagParser *P, Flags *F) XRAY_NEVER_INSTRUMENT {
  33 #define XRAY_FLAG(Type, Name, DefaultValue, Description)                       \
  34   RegisterFlag(P, #Name, Description, &F->Name);
  35 #include "xray_flags.inc"
  36 #undef XRAY_FLAG
  37 }
  38
  39 // This function, as defined with the help of a macro meant to be introduced at
  40 // build time of the XRay runtime, passes in a statically defined list of
  41 // options that control XRay. This means users/deployments can tweak the
  42 // defaults that override the hard-coded defaults in the xray_flags.inc at
  43 // compile-time using the XRAY_DEFAULT_OPTIONS macro.
  44 const char *useCompilerDefinedFlags() XRAY_NEVER_INSTRUMENT {
  45 #ifdef XRAY_DEFAULT_OPTIONS
  46   // Do the double-layered string conversion to prevent badly crafted strings
  47   // provided through the XRAY_DEFAULT_OPTIONS from causing compilation issues
  48   // (or changing the semantics of the implementation through the macro). This
  49   // ensures that we convert whatever XRAY_DEFAULT_OPTIONS is defined as a
  50   // string literal.
  51   return SANITIZER_STRINGIFY(XRAY_DEFAULT_OPTIONS);
  52 #else
  53   return "";
  54 #endif
  55 }
  56
  57 void initializeFlags() XRAY_NEVER_INSTRUMENT {
  58   SetCommonFlagsDefaults();
  59   auto *F = flags();
  60   F->setDefaults();
  61
  62   FlagParser XRayParser;
  63   registerXRayFlags(&XRayParser, F);
  64   RegisterCommonFlags(&XRayParser);
  65
  66   // Use options defaulted at compile-time for the runtime.
  67   const char *XRayCompileFlags = useCompilerDefinedFlags();
  68   XRayParser.ParseString(XRayCompileFlags);
  69
  70   // Use options provided at build time of the instrumented program.
  71   const char *XRayDefaultOptions = __xray_default_options();
  72   XRayParser.ParseString(XRayDefaultOptions);
  73
  74   // Override from environment variables.
  75   XRayParser.ParseStringFromEnv("XRAY_OPTIONS");
  76
  77   // Override from command line.
  78   InitializeCommonFlags();
  79
  80   if (Verbosity())
  81     ReportUnrecognizedFlags();
  82
  83   if (common_flags()->help) {
  84     XRayParser.PrintFlagDescriptions();
  85   }
  86 }
  87
  88 } // namespace __xray
  89
  90 SANITIZER_INTERFACE_WEAK_DEF(const char *, __xray_default_options, void) {
  91   return "";
  92 }