1 FileCheck - Flexible pattern matching file verifier
2 ===================================================
7 **FileCheck** *match-filename* [*--check-prefix=XXX*] [*--strict-whitespace*]
12 **FileCheck** reads two files (one from standard input, and one specified on the
13 command line) and uses one to verify the other. This behavior is particularly
14 useful for the testsuite, which wants to verify that the output of some tool
15 (e.g. llc) contains the expected information (for example, a movsd from esp or
16 whatever is interesting). This is similar to using grep, but it is optimized
17 for matching multiple different inputs in one file in a specific order.
19 The *match-filename* file specifies the file that contains the patterns to
20 match. The file to verify is always read from standard input.
27 Print a summary of command line options.
29 **--check-prefix** *prefix*
31 FileCheck searches the contents of *match-filename* for patterns to match. By
32 default, these patterns are prefixed with "``CHECK:``". If you'd like to use a
33 different prefix (e.g. because the same input file is checking multiple
34 different tool or options), the **--check-prefix** argument allows you to specify
35 a specific prefix to match.
37 **--input-file** *filename*
39 File to check (defaults to stdin).
41 **--strict-whitespace**
43 By default, FileCheck canonicalizes input horizontal whitespace (spaces and
44 tabs) which causes it to ignore these differences (a space will match a tab).
45 The **--strict-whitespace** argument disables this behavior.
50 Show the version number of this program.
55 If **FileCheck** verifies that the file matches the expected contents, it exits
56 with 0. Otherwise, if not, or if an error occurs, it will exit with a non-zero
62 FileCheck is typically used from LLVM regression tests, being invoked on the RUN
63 line of the test. A simple example of using FileCheck from a RUN line looks
68 ; 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)
97 Here you can see some "``CHECK:``" lines specified in comments. Now you can
98 see how the file is piped into ``llvm-as``, then ``llc``, and the machine code
99 output is what we are verifying. FileCheck checks the machine code output to
100 verify that it matches what the "``CHECK:``" lines specify.
102 The syntax of the "``CHECK:``" lines is very simple: they are fixed strings that
103 must occur in order. FileCheck defaults to ignoring horizontal whitespace
104 differences (e.g. a space is allowed to match a tab) but otherwise, the contents
105 of the "``CHECK:``" line is required to match some thing in the test file exactly.
107 One nice thing about FileCheck (compared to grep) is that it allows merging
108 test cases together into logical groups. For example, because the test above
109 is checking for the "``sub1:``" and "``inc4:``" labels, it will not match
110 unless there is a "``subl``" in between those labels. If it existed somewhere
111 else in the file, that would not count: "``grep subl``" matches if "``subl``"
112 exists anywhere in the file.
114 The FileCheck -check-prefix option
115 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
117 The FileCheck ``-check-prefix`` option allows multiple test configurations to be
118 driven from one .ll file. This is useful in many circumstances, for example,
119 testing different architectural variants with 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 an 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
198 FileCheck Pattern Matching Syntax
199 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
201 The "``CHECK:``" and "``CHECK-NOT:``" directives both take a pattern to match.
202 For most uses of FileCheck, fixed string matching is perfectly sufficient. For
203 some things, a more flexible form of matching is desired. To support this,
204 FileCheck allows you to specify regular expressions in matching strings,
205 surrounded by double braces: ``{{yourregex}}``. Because we want to use fixed
206 string matching for a majority of what we do, FileCheck has been designed to
207 support mixing and matching fixed string matching with regular expressions.
208 This allows you to write things like this:
212 ; CHECK: movhpd {{[0-9]+}}(%esp), {{%xmm[0-7]}}
214 In this case, any offset from the ESP register will be allowed, and any xmm
215 register will be allowed.
217 Because regular expressions are enclosed with double braces, they are
218 visually distinct, and you don't need to use escape characters within the double
219 braces like you would in C. In the rare case that you want to match double
220 braces explicitly from the input, you can use something ugly like
221 ``{{[{][{]}}`` as your pattern.
226 It is often useful to match a pattern and then verify that it occurs again
227 later in the file. For codegen tests, this can be useful to allow any register,
228 but verify that that register is used consistently later. To do this, FileCheck
229 allows named variables to be defined and substituted into patterns. Here is a
235 ; CHECK: notw [[REGISTER:%[a-z]+]]
236 ; CHECK: andw {{.*}}[[REGISTER]]
238 The first check line matches a regex ``%[a-z]+`` and captures it into the
239 variable ``REGISTER``. The second line verifies that whatever is in
240 ``REGISTER`` occurs later in the file after an "``andw``". FileCheck variable
241 references are always contained in ``[[ ]]`` pairs, and their names can be
242 formed with the regex ``[a-zA-Z][a-zA-Z0-9]*``. If a colon follows the name,
243 then it is a definition of the variable; otherwise, it is a use.
245 FileCheck variables can be defined multiple times, and uses always get the
246 latest value. Note that variables are all read at the start of a "``CHECK``"
247 line and are all defined at the end. This means that if you have something
248 like "``CHECK: [[XYZ:.*]]x[[XYZ]]``", the check line will read the previous
249 value of the ``XYZ`` variable and define a new one after the match is
250 performed. If you need to do something like this you can probably take
251 advantage of the fact that FileCheck is not actually line-oriented when it
252 matches, this allows you to define two separate "``CHECK``" lines that match on
256 FileCheck Expressions
257 ~~~~~~~~~~~~~~~~~~~~~
260 Sometimes there's a need to verify output which refers line numbers of the match
261 file, e.g. when testing compiler diagnostics. This introduces a certain
262 fragility of the match file structure, as CHECK: lines contain absolute line
263 numbers in the same file, which have to be updated whenever line numbers change
264 due to text addition or deletion.
266 To support this case, FileCheck allows using ``[[@LINE]]``,
267 ``[[@LINE+<offset>]]``, ``[[@LINE-<offset>]]`` expressions in patterns. These
268 expressions expand to a number of the line where a pattern is located (with an
269 optional integer offset).
271 This way match patterns can be put near the relevant test lines and include
272 relative line number references, for example:
276 // CHECK: test.cpp:[[@LINE+4]]:6: error: expected ';' after top level declarator
277 // CHECK-NEXT: {{^int a}}
278 // CHECK-NEXT: {{^ \^}}
279 // CHECK-NEXT: {{^ ;}}