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 read from standard input unless the
22 :option:`--input-file` option is used.
29 Print a summary of command line options.
31 .. option:: --check-prefix prefix
33 FileCheck searches the contents of ``match-filename`` for patterns to
34 match. By default, these patterns are prefixed with "``CHECK:``".
35 If you'd like to use a different prefix (e.g. because the same input
36 file is checking multiple different tool or options), the
37 :option:`--check-prefix` argument allows you to specify one or more
38 prefixes to match. Multiple prefixes are useful for tests which might
39 change for different run options, but most lines remain the same.
41 .. option:: --input-file filename
43 File to check (defaults to stdin).
45 .. option:: --strict-whitespace
47 By default, FileCheck canonicalizes input horizontal whitespace (spaces and
48 tabs) which causes it to ignore these differences (a space will match a tab).
49 The :option:`--strict-whitespace` argument disables this behavior. End-of-line
50 sequences are canonicalized to UNIX-style ``\n`` in all modes.
52 .. option:: --implicit-check-not check-pattern
54 Adds implicit negative checks for the specified patterns between positive
55 checks. The option allows writing stricter tests without stuffing them with
58 For example, "``--implicit-check-not warning:``" can be useful when testing
59 diagnostic messages from tools that don't have an option similar to ``clang
60 -verify``. With this option FileCheck will verify that input does not contain
61 warnings not covered by any ``CHECK:`` patterns.
65 Show the version number of this program.
70 If :program:`FileCheck` verifies that the file matches the expected contents,
71 it exits with 0. Otherwise, if not, or if an error occurs, it will exit with a
77 FileCheck is typically used from LLVM regression tests, being invoked on the RUN
78 line of the test. A simple example of using FileCheck from a RUN line looks
83 ; RUN: llvm-as < %s | llc -march=x86-64 | FileCheck %s
85 This syntax says to pipe the current file ("``%s``") into ``llvm-as``, pipe
86 that into ``llc``, then pipe the output of ``llc`` into ``FileCheck``. This
87 means that FileCheck will be verifying its standard input (the llc output)
88 against the filename argument specified (the original ``.ll`` file specified by
89 "``%s``"). To see how this works, let's look at the rest of the ``.ll`` file
94 define void @sub1(i32* %p, i32 %v) {
98 %0 = tail call i32 @llvm.atomic.load.sub.i32.p0i32(i32* %p, i32 %v)
102 define void @inc4(i64* %p) {
106 %0 = tail call i64 @llvm.atomic.load.add.i64.p0i64(i64* %p, i64 1)
110 Here you can see some "``CHECK:``" lines specified in comments. Now you can
111 see how the file is piped into ``llvm-as``, then ``llc``, and the machine code
112 output is what we are verifying. FileCheck checks the machine code output to
113 verify that it matches what the "``CHECK:``" lines specify.
115 The syntax of the "``CHECK:``" lines is very simple: they are fixed strings that
116 must occur in order. FileCheck defaults to ignoring horizontal whitespace
117 differences (e.g. a space is allowed to match a tab) but otherwise, the contents
118 of the "``CHECK:``" line is required to match some thing in the test file exactly.
120 One nice thing about FileCheck (compared to grep) is that it allows merging
121 test cases together into logical groups. For example, because the test above
122 is checking for the "``sub1:``" and "``inc4:``" labels, it will not match
123 unless there is a "``subl``" in between those labels. If it existed somewhere
124 else in the file, that would not count: "``grep subl``" matches if "``subl``"
125 exists anywhere in the file.
127 The FileCheck -check-prefix option
128 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
130 The FileCheck :option:`-check-prefix` option allows multiple test
131 configurations to be driven from one `.ll` file. This is useful in many
132 circumstances, for example, testing different architectural variants with
133 :program:`llc`. Here's a simple example:
137 ; RUN: llvm-as < %s | llc -mtriple=i686-apple-darwin9 -mattr=sse41 \
138 ; RUN: | FileCheck %s -check-prefix=X32
139 ; RUN: llvm-as < %s | llc -mtriple=x86_64-apple-darwin9 -mattr=sse41 \
140 ; RUN: | FileCheck %s -check-prefix=X64
142 define <4 x i32> @pinsrd_1(i32 %s, <4 x i32> %tmp) nounwind {
143 %tmp1 = insertelement <4 x i32>; %tmp, i32 %s, i32 1
146 ; X32: pinsrd $1, 4(%esp), %xmm0
149 ; X64: pinsrd $1, %edi, %xmm0
152 In this case, we're testing that we get the expected code generation with
153 both 32-bit and 64-bit code generation.
155 The "CHECK-NEXT:" directive
156 ~~~~~~~~~~~~~~~~~~~~~~~~~~~
158 Sometimes you want to match lines and would like to verify that matches
159 happen on exactly consecutive lines with no other lines in between them. In
160 this case, you can use "``CHECK:``" and "``CHECK-NEXT:``" directives to specify
161 this. If you specified a custom check prefix, just use "``<PREFIX>-NEXT:``".
162 For example, something like this works as you'd expect:
166 define void @t2(<2 x double>* %r, <2 x double>* %A, double %B) {
167 %tmp3 = load <2 x double>* %A, align 16
168 %tmp7 = insertelement <2 x double> undef, double %B, i32 0
169 %tmp9 = shufflevector <2 x double> %tmp3,
171 <2 x i32> < i32 0, i32 2 >
172 store <2 x double> %tmp9, <2 x double>* %r, align 16
176 ; CHECK: movl 8(%esp), %eax
177 ; CHECK-NEXT: movapd (%eax), %xmm0
178 ; CHECK-NEXT: movhpd 12(%esp), %xmm0
179 ; CHECK-NEXT: movl 4(%esp), %eax
180 ; CHECK-NEXT: movapd %xmm0, (%eax)
184 "``CHECK-NEXT:``" directives reject the input unless there is exactly one
185 newline between it and the previous directive. A "``CHECK-NEXT:``" cannot be
186 the first directive in a file.
188 The "CHECK-SAME:" directive
189 ~~~~~~~~~~~~~~~~~~~~~~~~~~~
191 Sometimes you want to match lines and would like to verify that matches happen
192 on the same line as the previous match. In this case, you can use "``CHECK:``"
193 and "``CHECK-SAME:``" directives to specify this. If you specified a custom
194 check prefix, just use "``<PREFIX>-SAME:``".
196 "``CHECK-SAME:``" is particularly powerful in conjunction with "``CHECK-NOT:``"
199 For example, the following works like you'd expect:
203 !0 = !DILocation(line: 5, scope: !1, inlinedAt: !2)
205 ; CHECK: !DILocation(line: 5,
207 ; CHECK-SAME: scope: ![[SCOPE:[0-9]+]]
209 "``CHECK-SAME:``" directives reject the input if there are any newlines between
210 it and the previous directive. A "``CHECK-SAME:``" cannot be the first
213 The "CHECK-NOT:" directive
214 ~~~~~~~~~~~~~~~~~~~~~~~~~~
216 The "``CHECK-NOT:``" directive is used to verify that a string doesn't occur
217 between two matches (or before the first match, or after the last match). For
218 example, to verify that a load is removed by a transformation, a test like this
223 define i8 @coerce_offset0(i32 %V, i32* %P) {
224 store i32 %V, i32* %P
226 %P2 = bitcast i32* %P to i8*
227 %P3 = getelementptr i8* %P2, i32 2
231 ; CHECK: @coerce_offset0
236 The "CHECK-DAG:" directive
237 ~~~~~~~~~~~~~~~~~~~~~~~~~~
239 If it's necessary to match strings that don't occur in a strictly sequential
240 order, "``CHECK-DAG:``" could be used to verify them between two matches (or
241 before the first match, or after the last match). For example, clang emits
242 vtable globals in reverse order. Using ``CHECK-DAG:``, we can keep the checks
243 in the natural order:
247 // RUN: %clang_cc1 %s -emit-llvm -o - | FileCheck %s
249 struct Foo { virtual void method(); };
250 Foo f; // emit vtable
251 // CHECK-DAG: @_ZTV3Foo =
253 struct Bar { virtual void method(); };
255 // CHECK-DAG: @_ZTV3Bar =
257 ``CHECK-NOT:`` directives could be mixed with ``CHECK-DAG:`` directives to
258 exclude strings between the surrounding ``CHECK-DAG:`` directives. As a result,
259 the surrounding ``CHECK-DAG:`` directives cannot be reordered, i.e. all
260 occurrences matching ``CHECK-DAG:`` before ``CHECK-NOT:`` must not fall behind
261 occurrences matching ``CHECK-DAG:`` after ``CHECK-NOT:``. For example,
269 This case will reject input strings where ``BEFORE`` occurs after ``AFTER``.
271 With captured variables, ``CHECK-DAG:`` is able to match valid topological
272 orderings of a DAG with edges from the definition of a variable to its use.
273 It's useful, e.g., when your test cases need to match different output
274 sequences from the instruction scheduler. For example,
278 ; CHECK-DAG: add [[REG1:r[0-9]+]], r1, r2
279 ; CHECK-DAG: add [[REG2:r[0-9]+]], r3, r4
280 ; CHECK: mul r5, [[REG1]], [[REG2]]
282 In this case, any order of that two ``add`` instructions will be allowed.
284 If you are defining `and` using variables in the same ``CHECK-DAG:`` block,
285 be aware that the definition rule can match `after` its use.
287 So, for instance, the code below will pass:
291 ; CHECK-DAG: vmov.32 [[REG2:d[0-9]+]][0]
292 ; CHECK-DAG: vmov.32 [[REG2]][1]
296 While this other code, will not:
300 ; CHECK-DAG: vmov.32 [[REG2:d[0-9]+]][0]
301 ; CHECK-DAG: vmov.32 [[REG2]][1]
305 While this can be very useful, it's also dangerous, because in the case of
306 register sequence, you must have a strong order (read before write, copy before
307 use, etc). If the definition your test is looking for doesn't match (because
308 of a bug in the compiler), it may match further away from the use, and mask
311 In those cases, to enforce the order, use a non-DAG directive between DAG-blocks.
313 The "CHECK-LABEL:" directive
314 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
316 Sometimes in a file containing multiple tests divided into logical blocks, one
317 or more ``CHECK:`` directives may inadvertently succeed by matching lines in a
318 later block. While an error will usually eventually be generated, the check
319 flagged as causing the error may not actually bear any relationship to the
320 actual source of the problem.
322 In order to produce better error messages in these cases, the "``CHECK-LABEL:``"
323 directive can be used. It is treated identically to a normal ``CHECK``
324 directive except that FileCheck makes an additional assumption that a line
325 matched by the directive cannot also be matched by any other check present in
326 ``match-filename``; this is intended to be used for lines containing labels or
327 other unique identifiers. Conceptually, the presence of ``CHECK-LABEL`` divides
328 the input stream into separate blocks, each of which is processed independently,
329 preventing a ``CHECK:`` directive in one block matching a line in another block.
334 define %struct.C* @C_ctor_base(%struct.C* %this, i32 %x) {
336 ; CHECK-LABEL: C_ctor_base:
337 ; CHECK: mov [[SAVETHIS:r[0-9]+]], r0
338 ; CHECK: bl A_ctor_base
339 ; CHECK: mov r0, [[SAVETHIS]]
340 %0 = bitcast %struct.C* %this to %struct.A*
341 %call = tail call %struct.A* @A_ctor_base(%struct.A* %0)
342 %1 = bitcast %struct.C* %this to %struct.B*
343 %call2 = tail call %struct.B* @B_ctor_base(%struct.B* %1, i32 %x)
347 define %struct.D* @D_ctor_base(%struct.D* %this, i32 %x) {
349 ; CHECK-LABEL: D_ctor_base:
351 The use of ``CHECK-LABEL:`` directives in this case ensures that the three
352 ``CHECK:`` directives only accept lines corresponding to the body of the
353 ``@C_ctor_base`` function, even if the patterns match lines found later in
354 the file. Furthermore, if one of these three ``CHECK:`` directives fail,
355 FileCheck will recover by continuing to the next block, allowing multiple test
356 failures to be detected in a single invocation.
358 There is no requirement that ``CHECK-LABEL:`` directives contain strings that
359 correspond to actual syntactic labels in a source or output language: they must
360 simply uniquely match a single line in the file being verified.
362 ``CHECK-LABEL:`` directives cannot contain variable definitions or uses.
364 FileCheck Pattern Matching Syntax
365 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
367 All FileCheck directives take a pattern to match.
368 For most uses of FileCheck, fixed string matching is perfectly sufficient. For
369 some things, a more flexible form of matching is desired. To support this,
370 FileCheck allows you to specify regular expressions in matching strings,
371 surrounded by double braces: ``{{yourregex}}``. Because we want to use fixed
372 string matching for a majority of what we do, FileCheck has been designed to
373 support mixing and matching fixed string matching with regular expressions.
374 This allows you to write things like this:
378 ; CHECK: movhpd {{[0-9]+}}(%esp), {{%xmm[0-7]}}
380 In this case, any offset from the ESP register will be allowed, and any xmm
381 register will be allowed.
383 Because regular expressions are enclosed with double braces, they are
384 visually distinct, and you don't need to use escape characters within the double
385 braces like you would in C. In the rare case that you want to match double
386 braces explicitly from the input, you can use something ugly like
387 ``{{[{][{]}}`` as your pattern.
392 It is often useful to match a pattern and then verify that it occurs again
393 later in the file. For codegen tests, this can be useful to allow any register,
394 but verify that that register is used consistently later. To do this,
395 :program:`FileCheck` allows named variables to be defined and substituted into
396 patterns. Here is a simple example:
401 ; CHECK: notw [[REGISTER:%[a-z]+]]
402 ; CHECK: andw {{.*}}[[REGISTER]]
404 The first check line matches a regex ``%[a-z]+`` and captures it into the
405 variable ``REGISTER``. The second line verifies that whatever is in
406 ``REGISTER`` occurs later in the file after an "``andw``". :program:`FileCheck`
407 variable references are always contained in ``[[ ]]`` pairs, and their names can
408 be formed with the regex ``[a-zA-Z][a-zA-Z0-9]*``. If a colon follows the name,
409 then it is a definition of the variable; otherwise, it is a use.
411 :program:`FileCheck` variables can be defined multiple times, and uses always
412 get the latest value. Variables can also be used later on the same line they
413 were defined on. For example:
417 ; CHECK: op [[REG:r[0-9]+]], [[REG]]
419 Can be useful if you want the operands of ``op`` to be the same register,
420 and don't care exactly which register it is.
422 FileCheck Expressions
423 ~~~~~~~~~~~~~~~~~~~~~
425 Sometimes there's a need to verify output which refers line numbers of the
426 match file, e.g. when testing compiler diagnostics. This introduces a certain
427 fragility of the match file structure, as "``CHECK:``" lines contain absolute
428 line numbers in the same file, which have to be updated whenever line numbers
429 change due to text addition or deletion.
431 To support this case, FileCheck allows using ``[[@LINE]]``,
432 ``[[@LINE+<offset>]]``, ``[[@LINE-<offset>]]`` expressions in patterns. These
433 expressions expand to a number of the line where a pattern is located (with an
434 optional integer offset).
436 This way match patterns can be put near the relevant test lines and include
437 relative line number references, for example:
441 // CHECK: test.cpp:[[@LINE+4]]:6: error: expected ';' after top level declarator
442 // CHECK-NEXT: {{^int a}}
443 // CHECK-NEXT: {{^ \^}}
444 // CHECK-NEXT: {{^ ;}}