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   // Override from environment variables.
71   XRayParser.ParseStringFromEnv("XRAY_OPTIONS");
72 
73   // Override from command line.
74   InitializeCommonFlags();
75 
76   if (Verbosity())
77     ReportUnrecognizedFlags();
78 
79   if (common_flags()->help) {
80     XRayParser.PrintFlagDescriptions();
81   }
82 }
83 
84 } // namespace __xray
85