1========================================
2Compiler-rt Testing Infrastructure Guide
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4
5.. contents::
6   :local:
7
8Overview
9========
10
11This document is the reference manual for the compiler-rt modifications to the
12testing infrastructure. Documentation for the infrastructure itself can be found at
13:ref:`llvm_testing_guide`.
14
15LLVM testing infrastructure organization
16========================================
17
18The compiler-rt testing infrastructure contains regression tests which are run
19as part of the usual ``make check-all`` and are expected to always pass -- they
20should be run before every commit.
21
22Quick start
23===========
24
25The regressions tests are in the "compiler-rt" module and are normally checked
26out in the directory ``llvm/projects/compiler-rt/test``. Use ``make check-all``
27to run the regression tests after building compiler-rt.
28
29REQUIRES, XFAIL, etc.
30---------------------
31
32Sometimes it is necessary to restrict a test to a specific target or mark it as
33an "expected fail" or XFAIL. This is normally achieved using ``REQUIRES:`` or
34``XFAIL:`` with a substring of LLVM's default target triple. Unfortunately, the
35behaviour of this is somewhat quirky in compiler-rt. There are two main
36pitfalls to avoid.
37
38The first pitfall is that these directives perform a substring match on the
39triple and as such ``XFAIL: mips`` affects more triples than expected. For
40example, ``mips-linux-gnu``, ``mipsel-linux-gnu``, ``mips64-linux-gnu``, and
41``mips64el-linux-gnu`` will all match a ``XFAIL: mips`` directive. Including a
42trailing ``-`` such as in ``XFAIL: mips-`` can help to mitigate this quirk but
43even that has issues as described below.
44
45The second pitfall is that the default target triple is often inappropriate for
46compiler-rt tests since compiler-rt tests may be compiled for multiple targets.
47For example, a typical build on an ``x86_64-linux-gnu`` host will often run the
48tests for both x86_64 and i386. In this situation ``XFAIL: x86_64`` will mark
49both the x86_64 and i386 tests as an expected failure while ``XFAIL: i386``
50will have no effect at all.
51
52To remedy both pitfalls, compiler-rt tests provide a feature string which can
53be used to specify a single target. This string is of the form
54``target-is-${arch}`` where ``${arch}}`` is one of the values from the
55following lines of the CMake output::
56
57  -- Compiler-RT supported architectures: x86_64;i386
58  -- Builtin supported architectures: i386;x86_64
59
60So for example ``XFAIL: target-is-x86_64`` will mark a test as expected to fail
61on x86_64 without also affecting the i386 test and ``XFAIL: target-is-i386``
62will mark a test as expected to fail on i386 even if the default target triple
63is ``x86_64-linux-gnu``. Directives that use these ``target-is-${arch}`` string
64require exact matches so ``XFAIL: target-is-mips``,
65``XFAIL: target-is-mipsel``, ``XFAIL: target-is-mips64``, and
66``XFAIL: target-is-mips64el`` all refer to different MIPS targets.
67