README.md
1scan-build
2==========
3
4A package designed to wrap a build so that all calls to gcc/clang are
5intercepted and logged into a [compilation database][1] and/or piped to
6the clang static analyzer. Includes intercept-build tool, which logs
7the build, as well as scan-build tool, which logs the build and runs
8the clang static analyzer on it.
9
10Portability
11-----------
12
13Should be working on UNIX operating systems.
14
15- It has been tested on FreeBSD, GNU/Linux and OS X.
16- Prepared to work on windows, but need help to make it.
17
18
19Prerequisites
20-------------
21
221. **python** interpreter (version 3.6 or later).
23
24
25How to use
26----------
27
28To run the Clang static analyzer against a project goes like this:
29
30 $ scan-build <your build command>
31
32To generate a compilation database file goes like this:
33
34 $ intercept-build <your build command>
35
36To run the Clang static analyzer against a project with compilation database
37goes like this:
38
39 $ analyze-build
40
41Use `--help` to know more about the commands.
42
43
44How to use the experimental Cross Translation Unit analysis
45-----------------------------------------------------------
46
47To run the CTU analysis, a compilation database file has to be created:
48
49 $ intercept-build <your build command>
50
51To run the Clang Static Analyzer against a compilation database
52with CTU analysis enabled, execute:
53
54 $ analyze-build --ctu
55
56For CTU analysis an additional (external definition) collection-phase is required.
57For debugging purposes, it is possible to separately execute the collection
58and the analysis phase. By doing this, the intermediate files used for
59the analysis are kept on the disk in `./ctu-dir`.
60
61 # Collect and store the data required by the CTU analysis
62 $ analyze-build --ctu-collect-only
63
64 # Analyze using the previously collected data
65 $ analyze-build --ctu-analyze-only
66
67Use `--help` to get more information about the commands.
68
69
70Limitations
71-----------
72
73Generally speaking, the `intercept-build` and `analyze-build` tools together
74does the same job as `scan-build` does. So, you can expect the same output
75from this line as simple `scan-build` would do:
76
77 $ intercept-build <your build command> && analyze-build
78
79The major difference is how and when the analyzer is run. The `scan-build`
80tool has three distinct model to run the analyzer:
81
821. Use compiler wrappers to make actions.
83 The compiler wrappers does run the real compiler and the analyzer.
84 This is the default behaviour, can be enforced with `--override-compiler`
85 flag.
86
872. Use special library to intercept compiler calls during the build process.
88 The analyzer run against each modules after the build finished.
89 Use `--intercept-first` flag to get this model.
90
913. Use compiler wrappers to intercept compiler calls during the build process.
92 The analyzer run against each modules after the build finished.
93 Use `--intercept-first` and `--override-compiler` flags together to get
94 this model.
95
96The 1. and 3. are using compiler wrappers, which works only if the build
97process respects the `CC` and `CXX` environment variables. (Some build
98process can override these variable as command line parameter only. This case
99you need to pass the compiler wrappers manually. eg.: `intercept-build
100--override-compiler make CC=intercept-cc CXX=intercept-c++ all` where the
101original build command would have been `make all` only.)
102
103The 1. runs the analyzer right after the real compilation. So, if the build
104process removes removes intermediate modules (generated sources) the analyzer
105output still kept.
106
107The 2. and 3. generate the compilation database first, and filters out those
108modules which are not exists. So, it's suitable for incremental analysis during
109the development.
110
111The 2. mode is available only on FreeBSD and Linux. Where library preload
112is available from the dynamic loader. Not supported on OS X (unless System
113Integrity Protection feature is turned off).
114
115`intercept-build` command uses only the 2. and 3. mode to generate the
116compilation database. `analyze-build` does only run the analyzer against the
117captured compiler calls.
118
119
120Known problems
121--------------
122
123Because it uses `LD_PRELOAD` or `DYLD_INSERT_LIBRARIES` environment variables,
124it does not append to it, but overrides it. So builds which are using these
125variables might not work. (I don't know any build tool which does that, but
126please let me know if you do.)
127
128
129Problem reports
130---------------
131
132If you find a bug in this documentation or elsewhere in the program or would
133like to propose an improvement, please use the project's [issue tracker][3].
134Please describing the bug and where you found it. If you have a suggestion
135how to fix it, include that as well. Patches are also welcome.
136
137
138License
139-------
140
141The project is licensed under Apache-2.0 with LLVM exceptions.
142See LICENSE.TXT for details.
143
144 [1]: http://clang.llvm.org/docs/JSONCompilationDatabase.html
145 [2]: https://pypi.python.org/pypi/scan-build
146 [3]: https://llvm.org/bugs/enter_bug.cgi?product=clang
147