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.
54 Show the version number of this program.
59 If :program:`FileCheck` verifies that the file matches the expected contents,
60 it exits with 0. Otherwise, if not, or if an error occurs, it will exit with a
66 FileCheck is typically used from LLVM regression tests, being invoked on the RUN
67 line of the test. A simple example of using FileCheck from a RUN line looks
72 ; RUN: llvm-as < %s | llc -march=x86-64 | FileCheck %s
74 This syntax says to pipe the current file ("``%s``") into ``llvm-as``, pipe
75 that into ``llc``, then pipe the output of ``llc`` into ``FileCheck``. This
76 means that FileCheck will be verifying its standard input (the llc output)
77 against the filename argument specified (the original ``.ll`` file specified by
78 "``%s``"). To see how this works, let's look at the rest of the ``.ll`` file
83 define void @sub1(i32* %p, i32 %v) {
87 %0 = tail call i32 @llvm.atomic.load.sub.i32.p0i32(i32* %p, i32 %v)
91 define void @inc4(i64* %p) {
95 %0 = tail call i64 @llvm.atomic.load.add.i64.p0i64(i64* %p, i64 1)
99 Here you can see some "``CHECK:``" lines specified in comments. Now you can
100 see how the file is piped into ``llvm-as``, then ``llc``, and the machine code
101 output is what we are verifying. FileCheck checks the machine code output to
102 verify that it matches what the "``CHECK:``" lines specify.
104 The syntax of the "``CHECK:``" lines is very simple: they are fixed strings that
105 must occur in order. FileCheck defaults to ignoring horizontal whitespace
106 differences (e.g. a space is allowed to match a tab) but otherwise, the contents
107 of the "``CHECK:``" line is required to match some thing in the test file exactly.
109 One nice thing about FileCheck (compared to grep) is that it allows merging
110 test cases together into logical groups. For example, because the test above
111 is checking for the "``sub1:``" and "``inc4:``" labels, it will not match
112 unless there is a "``subl``" in between those labels. If it existed somewhere
113 else in the file, that would not count: "``grep subl``" matches if "``subl``"
114 exists anywhere in the file.
116 The FileCheck -check-prefix option
117 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
119 The FileCheck :option:`-check-prefix` option allows multiple test
120 configurations to be driven from one `.ll` file. This is useful in many
121 circumstances, for example, testing different architectural variants with
122 :program:`llc`. Here's a simple example:
126 ; RUN: llvm-as < %s | llc -mtriple=i686-apple-darwin9 -mattr=sse41 \
127 ; RUN: | FileCheck %s -check-prefix=X32
128 ; RUN: llvm-as < %s | llc -mtriple=x86_64-apple-darwin9 -mattr=sse41 \
129 ; RUN: | FileCheck %s -check-prefix=X64
131 define <4 x i32> @pinsrd_1(i32 %s, <4 x i32> %tmp) nounwind {
132 %tmp1 = insertelement <4 x i32>; %tmp, i32 %s, i32 1
135 ; X32: pinsrd $1, 4(%esp), %xmm0
138 ; X64: pinsrd $1, %edi, %xmm0
141 In this case, we're testing that we get the expected code generation with
142 both 32-bit and 64-bit code generation.
144 The "CHECK-NEXT:" directive
145 ~~~~~~~~~~~~~~~~~~~~~~~~~~~
147 Sometimes you want to match lines and would like to verify that matches
148 happen on exactly consecutive lines with no other lines in between them. In
149 this case, you can use "``CHECK:``" and "``CHECK-NEXT:``" directives to specify
150 this. If you specified a custom check prefix, just use "``<PREFIX>-NEXT:``".
151 For example, something like this works as you'd expect:
155 define void @t2(<2 x double>* %r, <2 x double>* %A, double %B) {
156 %tmp3 = load <2 x double>* %A, align 16
157 %tmp7 = insertelement <2 x double> undef, double %B, i32 0
158 %tmp9 = shufflevector <2 x double> %tmp3,
160 <2 x i32> < i32 0, i32 2 >
161 store <2 x double> %tmp9, <2 x double>* %r, align 16
165 ; CHECK: movl 8(%esp), %eax
166 ; CHECK-NEXT: movapd (%eax), %xmm0
167 ; CHECK-NEXT: movhpd 12(%esp), %xmm0
168 ; CHECK-NEXT: movl 4(%esp), %eax
169 ; CHECK-NEXT: movapd %xmm0, (%eax)
173 "``CHECK-NEXT:``" directives reject the input unless there is exactly one
174 newline between it and the previous directive. A "``CHECK-NEXT:``" cannot be
175 the first directive in a file.
177 The "CHECK-NOT:" directive
178 ~~~~~~~~~~~~~~~~~~~~~~~~~~
180 The "``CHECK-NOT:``" directive is used to verify that a string doesn't occur
181 between two matches (or before the first match, or after the last match). For
182 example, to verify that a load is removed by a transformation, a test like this
187 define i8 @coerce_offset0(i32 %V, i32* %P) {
188 store i32 %V, i32* %P
190 %P2 = bitcast i32* %P to i8*
191 %P3 = getelementptr i8* %P2, i32 2
195 ; CHECK: @coerce_offset0
200 The "CHECK-DAG:" directive
201 ~~~~~~~~~~~~~~~~~~~~~~~~~~
203 If it's necessary to match strings that don't occur in a strictly sequential
204 order, "``CHECK-DAG:``" could be used to verify them between two matches (or
205 before the first match, or after the last match). For example, clang emits
206 vtable globals in reverse order. Using ``CHECK-DAG:``, we can keep the checks
207 in the natural order:
211 // RUN: %clang_cc1 %s -emit-llvm -o - | FileCheck %s
213 struct Foo { virtual void method(); };
214 Foo f; // emit vtable
215 // CHECK-DAG: @_ZTV3Foo =
217 struct Bar { virtual void method(); };
219 // CHECK-DAG: @_ZTV3Bar =
221 ``CHECK-NOT:`` directives could be mixed with ``CHECK-DAG:`` directives to
222 exclude strings between the surrounding ``CHECK-DAG:`` directives. As a result,
223 the surrounding ``CHECK-DAG:`` directives cannot be reordered, i.e. all
224 occurrences matching ``CHECK-DAG:`` before ``CHECK-NOT:`` must not fall behind
225 occurrences matching ``CHECK-DAG:`` after ``CHECK-NOT:``. For example,
233 This case will reject input strings where ``BEFORE`` occurs after ``AFTER``.
235 With captured variables, ``CHECK-DAG:`` is able to match valid topological
236 orderings of a DAG with edges from the definition of a variable to its use.
237 It's useful, e.g., when your test cases need to match different output
238 sequences from the instruction scheduler. For example,
242 ; CHECK-DAG: add [[REG1:r[0-9]+]], r1, r2
243 ; CHECK-DAG: add [[REG2:r[0-9]+]], r3, r4
244 ; CHECK: mul r5, [[REG1]], [[REG2]]
246 In this case, any order of that two ``add`` instructions will be allowed.
248 If you are defining `and` using variables in the same ``CHECK-DAG:`` block,
249 be aware that the definition rule can match `after` its use.
251 So, for instance, the code below will pass:
255 ; CHECK-DAG: vmov.32 [[REG2:d[0-9]+]][0]
256 ; CHECK-DAG: vmov.32 [[REG2]][1]
260 While this other code, will not:
264 ; CHECK-DAG: vmov.32 [[REG2:d[0-9]+]][0]
265 ; CHECK-DAG: vmov.32 [[REG2]][1]
269 While this can be very useful, it's also dangerous, because in the case of
270 register sequence, you must have a strong order (read before write, copy before
271 use, etc). If the definition your test is looking for doesn't match (because
272 of a bug in the compiler), it may match further away from the use, and mask
275 In those cases, to enforce the order, use a non-DAG directive between DAG-blocks.
277 The "CHECK-LABEL:" directive
278 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
280 Sometimes in a file containing multiple tests divided into logical blocks, one
281 or more ``CHECK:`` directives may inadvertently succeed by matching lines in a
282 later block. While an error will usually eventually be generated, the check
283 flagged as causing the error may not actually bear any relationship to the
284 actual source of the problem.
286 In order to produce better error messages in these cases, the "``CHECK-LABEL:``"
287 directive can be used. It is treated identically to a normal ``CHECK``
288 directive except that FileCheck makes an additional assumption that a line
289 matched by the directive cannot also be matched by any other check present in
290 ``match-filename``; this is intended to be used for lines containing labels or
291 other unique identifiers. Conceptually, the presence of ``CHECK-LABEL`` divides
292 the input stream into separate blocks, each of which is processed independently,
293 preventing a ``CHECK:`` directive in one block matching a line in another block.
298 define %struct.C* @C_ctor_base(%struct.C* %this, i32 %x) {
300 ; CHECK-LABEL: C_ctor_base:
301 ; CHECK: mov [[SAVETHIS:r[0-9]+]], r0
302 ; CHECK: bl A_ctor_base
303 ; CHECK: mov r0, [[SAVETHIS]]
304 %0 = bitcast %struct.C* %this to %struct.A*
305 %call = tail call %struct.A* @A_ctor_base(%struct.A* %0)
306 %1 = bitcast %struct.C* %this to %struct.B*
307 %call2 = tail call %struct.B* @B_ctor_base(%struct.B* %1, i32 %x)
311 define %struct.D* @D_ctor_base(%struct.D* %this, i32 %x) {
313 ; CHECK-LABEL: D_ctor_base:
315 The use of ``CHECK-LABEL:`` directives in this case ensures that the three
316 ``CHECK:`` directives only accept lines corresponding to the body of the
317 ``@C_ctor_base`` function, even if the patterns match lines found later in
318 the file. Furthermore, if one of these three ``CHECK:`` directives fail,
319 FileCheck will recover by continuing to the next block, allowing multiple test
320 failures to be detected in a single invocation.
322 There is no requirement that ``CHECK-LABEL:`` directives contain strings that
323 correspond to actual syntactic labels in a source or output language: they must
324 simply uniquely match a single line in the file being verified.
326 ``CHECK-LABEL:`` directives cannot contain variable definitions or uses.
328 FileCheck Pattern Matching Syntax
329 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
331 The "``CHECK:``" and "``CHECK-NOT:``" directives both take a pattern to match.
332 For most uses of FileCheck, fixed string matching is perfectly sufficient. For
333 some things, a more flexible form of matching is desired. To support this,
334 FileCheck allows you to specify regular expressions in matching strings,
335 surrounded by double braces: ``{{yourregex}}``. Because we want to use fixed
336 string matching for a majority of what we do, FileCheck has been designed to
337 support mixing and matching fixed string matching with regular expressions.
338 This allows you to write things like this:
342 ; CHECK: movhpd {{[0-9]+}}(%esp), {{%xmm[0-7]}}
344 In this case, any offset from the ESP register will be allowed, and any xmm
345 register will be allowed.
347 Because regular expressions are enclosed with double braces, they are
348 visually distinct, and you don't need to use escape characters within the double
349 braces like you would in C. In the rare case that you want to match double
350 braces explicitly from the input, you can use something ugly like
351 ``{{[{][{]}}`` as your pattern.
356 It is often useful to match a pattern and then verify that it occurs again
357 later in the file. For codegen tests, this can be useful to allow any register,
358 but verify that that register is used consistently later. To do this,
359 :program:`FileCheck` allows named variables to be defined and substituted into
360 patterns. Here is a simple example:
365 ; CHECK: notw [[REGISTER:%[a-z]+]]
366 ; CHECK: andw {{.*}}[[REGISTER]]
368 The first check line matches a regex ``%[a-z]+`` and captures it into the
369 variable ``REGISTER``. The second line verifies that whatever is in
370 ``REGISTER`` occurs later in the file after an "``andw``". :program:`FileCheck`
371 variable references are always contained in ``[[ ]]`` pairs, and their names can
372 be formed with the regex ``[a-zA-Z][a-zA-Z0-9]*``. If a colon follows the name,
373 then it is a definition of the variable; otherwise, it is a use.
375 :program:`FileCheck` variables can be defined multiple times, and uses always
376 get the latest value. Variables can also be used later on the same line they
377 were defined on. For example:
381 ; CHECK: op [[REG:r[0-9]+]], [[REG]]
383 Can be useful if you want the operands of ``op`` to be the same register,
384 and don't care exactly which register it is.
386 FileCheck Expressions
387 ~~~~~~~~~~~~~~~~~~~~~
389 Sometimes there's a need to verify output which refers line numbers of the
390 match file, e.g. when testing compiler diagnostics. This introduces a certain
391 fragility of the match file structure, as "``CHECK:``" lines contain absolute
392 line numbers in the same file, which have to be updated whenever line numbers
393 change due to text addition or deletion.
395 To support this case, FileCheck allows using ``[[@LINE]]``,
396 ``[[@LINE+<offset>]]``, ``[[@LINE-<offset>]]`` expressions in patterns. These
397 expressions expand to a number of the line where a pattern is located (with an
398 optional integer offset).
400 This way match patterns can be put near the relevant test lines and include
401 relative line number references, for example:
405 // CHECK: test.cpp:[[@LINE+4]]:6: error: expected ';' after top level declarator
406 // CHECK-NEXT: {{^int a}}
407 // CHECK-NEXT: {{^ \^}}
408 // CHECK-NEXT: {{^ ;}}