1 FileCheck - Flexible pattern matching file verifier
2 ===================================================
7 :program:`FileCheck` *match-filename* [*--check-prefix=XXX*] [*--strict-whitespace*]
12 :program:`FileCheck` reads two files (one from standard input, and one
13 specified on the command line) and uses one to verify the other. This
14 behavior is particularly useful for the testsuite, which wants to verify that
15 the output of some tool (e.g. :program:`llc`) contains the expected information
16 (for example, a movsd from esp or whatever is interesting). This is similar to
17 using :program:`grep`, but it is optimized for matching multiple different
18 inputs in one file in a specific order.
20 The ``match-filename`` file specifies the file that contains the patterns to
21 match. The file to verify is always read from standard input.
28 Print a summary of command line options.
30 .. option:: --check-prefix prefix
32 FileCheck searches the contents of ``match-filename`` for patterns to match.
33 By default, these patterns are prefixed with "``CHECK:``". If you'd like to
34 use a different prefix (e.g. because the same input file is checking multiple
35 different tool or options), the :option:`--check-prefix` argument allows you
36 to specify a specific prefix to match.
38 .. option:: --input-file filename
40 File to check (defaults to stdin).
42 .. option:: --strict-whitespace
44 By default, FileCheck canonicalizes input horizontal whitespace (spaces and
45 tabs) which causes it to ignore these differences (a space will match a tab).
46 The :option:`--strict-whitespace` argument disables this behavior. End-of-line
47 sequences are canonicalized to UNIX-style '\n' in all modes.
51 Show the version number of this program.
56 If :program:`FileCheck` verifies that the file matches the expected contents,
57 it exits with 0. Otherwise, if not, or if an error occurs, it will exit with a
63 FileCheck is typically used from LLVM regression tests, being invoked on the RUN
64 line of the test. A simple example of using FileCheck from a RUN line looks
69 ; RUN: llvm-as < %s | llc -march=x86-64 | FileCheck %s
71 This syntax says to pipe the current file ("``%s``") into ``llvm-as``, pipe
72 that into ``llc``, then pipe the output of ``llc`` into ``FileCheck``. This
73 means that FileCheck will be verifying its standard input (the llc output)
74 against the filename argument specified (the original ``.ll`` file specified by
75 "``%s``"). To see how this works, let's look at the rest of the ``.ll`` file
80 define void @sub1(i32* %p, i32 %v) {
84 %0 = tail call i32 @llvm.atomic.load.sub.i32.p0i32(i32* %p, i32 %v)
88 define void @inc4(i64* %p) {
92 %0 = tail call i64 @llvm.atomic.load.add.i64.p0i64(i64* %p, i64 1)
96 Here you can see some "``CHECK:``" lines specified in comments. Now you can
97 see how the file is piped into ``llvm-as``, then ``llc``, and the machine code
98 output is what we are verifying. FileCheck checks the machine code output to
99 verify that it matches what the "``CHECK:``" lines specify.
101 The syntax of the "``CHECK:``" lines is very simple: they are fixed strings that
102 must occur in order. FileCheck defaults to ignoring horizontal whitespace
103 differences (e.g. a space is allowed to match a tab) but otherwise, the contents
104 of the "``CHECK:``" line is required to match some thing in the test file exactly.
106 One nice thing about FileCheck (compared to grep) is that it allows merging
107 test cases together into logical groups. For example, because the test above
108 is checking for the "``sub1:``" and "``inc4:``" labels, it will not match
109 unless there is a "``subl``" in between those labels. If it existed somewhere
110 else in the file, that would not count: "``grep subl``" matches if "``subl``"
111 exists anywhere in the file.
113 The FileCheck -check-prefix option
114 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
116 The FileCheck :option:`-check-prefix` option allows multiple test
117 configurations to be driven from one `.ll` file. This is useful in many
118 circumstances, for example, testing different architectural variants with
119 :program:`llc`. Here's a simple example:
123 ; RUN: llvm-as < %s | llc -mtriple=i686-apple-darwin9 -mattr=sse41 \
124 ; RUN: | FileCheck %s -check-prefix=X32
125 ; RUN: llvm-as < %s | llc -mtriple=x86_64-apple-darwin9 -mattr=sse41 \
126 ; RUN: | FileCheck %s -check-prefix=X64
128 define <4 x i32> @pinsrd_1(i32 %s, <4 x i32> %tmp) nounwind {
129 %tmp1 = insertelement <4 x i32>; %tmp, i32 %s, i32 1
132 ; X32: pinsrd $1, 4(%esp), %xmm0
135 ; X64: pinsrd $1, %edi, %xmm0
138 In this case, we're testing that we get the expected code generation with
139 both 32-bit and 64-bit code generation.
141 The "CHECK-NEXT:" directive
142 ~~~~~~~~~~~~~~~~~~~~~~~~~~~
144 Sometimes you want to match lines and would like to verify that matches
145 happen on exactly consecutive lines with no other lines in between them. In
146 this case, you can use "``CHECK:``" and "``CHECK-NEXT:``" directives to specify
147 this. If you specified a custom check prefix, just use "``<PREFIX>-NEXT:``".
148 For example, something like this works as you'd expect:
152 define void @t2(<2 x double>* %r, <2 x double>* %A, double %B) {
153 %tmp3 = load <2 x double>* %A, align 16
154 %tmp7 = insertelement <2 x double> undef, double %B, i32 0
155 %tmp9 = shufflevector <2 x double> %tmp3,
157 <2 x i32> < i32 0, i32 2 >
158 store <2 x double> %tmp9, <2 x double>* %r, align 16
162 ; CHECK: movl 8(%esp), %eax
163 ; CHECK-NEXT: movapd (%eax), %xmm0
164 ; CHECK-NEXT: movhpd 12(%esp), %xmm0
165 ; CHECK-NEXT: movl 4(%esp), %eax
166 ; CHECK-NEXT: movapd %xmm0, (%eax)
170 "``CHECK-NEXT:``" directives reject the input unless there is exactly one
171 newline between it and the previous directive. A "``CHECK-NEXT:``" cannot be
172 the first directive in a file.
174 The "CHECK-NOT:" directive
175 ~~~~~~~~~~~~~~~~~~~~~~~~~~
177 The "``CHECK-NOT:``" directive is used to verify that a string doesn't occur
178 between two matches (or before the first match, or after the last match). For
179 example, to verify that a load is removed by a transformation, a test like this
184 define i8 @coerce_offset0(i32 %V, i32* %P) {
185 store i32 %V, i32* %P
187 %P2 = bitcast i32* %P to i8*
188 %P3 = getelementptr i8* %P2, i32 2
192 ; CHECK: @coerce_offset0
197 FileCheck Pattern Matching Syntax
198 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
200 The "``CHECK:``" and "``CHECK-NOT:``" directives both take a pattern to match.
201 For most uses of FileCheck, fixed string matching is perfectly sufficient. For
202 some things, a more flexible form of matching is desired. To support this,
203 FileCheck allows you to specify regular expressions in matching strings,
204 surrounded by double braces: ``{{yourregex}}``. Because we want to use fixed
205 string matching for a majority of what we do, FileCheck has been designed to
206 support mixing and matching fixed string matching with regular expressions.
207 This allows you to write things like this:
211 ; CHECK: movhpd {{[0-9]+}}(%esp), {{%xmm[0-7]}}
213 In this case, any offset from the ESP register will be allowed, and any xmm
214 register will be allowed.
216 Because regular expressions are enclosed with double braces, they are
217 visually distinct, and you don't need to use escape characters within the double
218 braces like you would in C. In the rare case that you want to match double
219 braces explicitly from the input, you can use something ugly like
220 ``{{[{][{]}}`` as your pattern.
225 It is often useful to match a pattern and then verify that it occurs again
226 later in the file. For codegen tests, this can be useful to allow any register,
227 but verify that that register is used consistently later. To do this,
228 :program:`FileCheck` allows named variables to be defined and substituted into
229 patterns. Here is a simple example:
234 ; CHECK: notw [[REGISTER:%[a-z]+]]
235 ; CHECK: andw {{.*}}[[REGISTER]]
237 The first check line matches a regex ``%[a-z]+`` and captures it into the
238 variable ``REGISTER``. The second line verifies that whatever is in
239 ``REGISTER`` occurs later in the file after an "``andw``". :program:`FileCheck`
240 variable references are always contained in ``[[ ]]`` pairs, and their names can
241 be formed with the regex ``[a-zA-Z][a-zA-Z0-9]*``. If a colon follows the name,
242 then it is a definition of the variable; otherwise, it is a use.
244 :program:`FileCheck` variables can be defined multiple times, and uses always
245 get the latest value. Variables can also be used later on the same line they
246 were defined on. For example:
250 ; CHECK: op [[REG:r[0-9]+]], [[REG]]
252 Can be useful if you want the operands of ``op`` to be the same register,
253 and don't care exactly which register it is.
255 FileCheck Expressions
256 ~~~~~~~~~~~~~~~~~~~~~
258 Sometimes there's a need to verify output which refers line numbers of the
259 match file, e.g. when testing compiler diagnostics. This introduces a certain
260 fragility of the match file structure, as "``CHECK:``" lines contain absolute
261 line numbers in the same file, which have to be updated whenever line numbers
262 change due to text addition or deletion.
264 To support this case, FileCheck allows using ``[[@LINE]]``,
265 ``[[@LINE+<offset>]]``, ``[[@LINE-<offset>]]`` expressions in patterns. These
266 expressions expand to a number of the line where a pattern is located (with an
267 optional integer offset).
269 This way match patterns can be put near the relevant test lines and include
270 relative line number references, for example:
274 // CHECK: test.cpp:[[@LINE+4]]:6: error: expected ';' after top level declarator
275 // CHECK-NEXT: {{^int a}}
276 // CHECK-NEXT: {{^ \^}}
277 // CHECK-NEXT: {{^ ;}}