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 The "CHECK-DAG:" directive
198 ~~~~~~~~~~~~~~~~~~~~~~~~~~
200 If it's necessary to match strings that don't occur in a strictly sequential
201 order, "``CHECK-DAG:``" could be used to verify them between two matches (or
202 before the first match, or after the last match). For example, clang emits
203 vtable globals in reverse order. Using ``CHECK-DAG:``, we can keep the checks
204 in the natural order:
208 // RUN: %clang_cc1 %s -emit-llvm -o - | FileCheck %s
210 struct Foo { virtual void method(); };
211 Foo f; // emit vtable
212 // CHECK-DAG: @_ZTV3Foo =
214 struct Bar { virtual void method(); };
216 // CHECK-DAG: @_ZTV3Bar =
219 With captured variables, ``CHECK-DAG:`` is able to match valid topological
220 orderings of a DAG with edges from the definition of a variable to its use.
221 It's useful, e.g., when your test cases need to match different output
222 sequences from the instruction scheduler. For example,
226 ; CHECK-DAG: add [[REG1:r[0-9]+]], r1, r2
227 ; CHECK-DAG: add [[REG2:r[0-9]+]], r3, r4
228 ; CHECK: mul r5, [[REG1]], [[REG2]]
230 In this case, any order of that two ``add`` instructions will be allowed.
232 ``CHECK-NOT:`` directives could be mixed with ``CHECK-DAG:`` directives to
233 exclude strings between the surrounding ``CHECK-DAG:`` directives. As a result,
234 the surrounding ``CHECK-DAG:`` directives cannot be reordered, i.e. all
235 occurrences matching ``CHECK-DAG:`` before ``CHECK-NOT:`` must not fall behind
236 occurrences matching ``CHECK-DAG:`` after ``CHECK-NOT:``. For example,
244 This case will reject input strings where ``BEFORE`` occurs after ``AFTER``.
246 The "CHECK-LABEL:" directive
247 ~~~~~~~~~~~~~~~~~~~~~~~~~~~
249 Sometimes in a file containing multiple tests divided into logical blocks, one
250 or more ``CHECK:`` directives may inadvertently succeed by matching lines in a
251 later block. While an error will usually eventually be generated, the check
252 flagged as causing the error may not actually bear any relationship to the
253 actual source of the problem.
255 In order to produce better error messages in these cases, the "``CHECK-LABEL:``"
256 directive can be used. It is treated identically to a normal ``CHECK``
257 directive except that the FileCheck utility makes an additional assumption that
258 a line matched by the directive cannot also be matched by any other check
259 present in ``match-filename``; this is intended to be used for lines containing
260 labels or other unique identifiers. Conceptually, the presence of
261 ``CHECK-LABEL`` divides the input stream into separate blocks, each of which is
262 processed independently, preventing a ``CHECK:`` directive in one block
263 matching a line in another block. For example,
267 define %struct.C* @C_ctor_base(%struct.C* %this, i32 %x) {
269 ; CHECK-LABEL: C_ctor_base:
270 ; CHECK: mov [[SAVETHIS:r[0-9]+]], r0
271 ; CHECK: bl A_ctor_base
272 ; CHECK: mov r0, [[SAVETHIS]]
273 %0 = bitcast %struct.C* %this to %struct.A*
274 %call = tail call %struct.A* @A_ctor_base(%struct.A* %0)
275 %1 = bitcast %struct.C* %this to %struct.B*
276 %call2 = tail call %struct.B* @B_ctor_base(%struct.B* %1, i32 %x)
280 define %struct.D* @D_ctor_base(%struct.D* %this, i32 %x) {
282 ; CHECK-LABEL: D_ctor_base:
284 The use of ``CHECK-LABEL:`` directives in this case ensures that the three
285 ``CHECK:`` directives only accept lines corresponding to the body of the
286 ``@C_ctor_base`` function, even if the patterns match lines found later in
289 There is no requirement that ``CHECK-LABEL:`` directives contain strings that
290 correspond to actual syntactic labels in a source or output language: they must
291 simply uniquely match a single line in the file being verified.
293 ``CHECK-LABEL:`` directives cannot contain variable definitions or uses.
295 FileCheck Pattern Matching Syntax
296 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
298 The "``CHECK:``" and "``CHECK-NOT:``" directives both take a pattern to match.
299 For most uses of FileCheck, fixed string matching is perfectly sufficient. For
300 some things, a more flexible form of matching is desired. To support this,
301 FileCheck allows you to specify regular expressions in matching strings,
302 surrounded by double braces: ``{{yourregex}}``. Because we want to use fixed
303 string matching for a majority of what we do, FileCheck has been designed to
304 support mixing and matching fixed string matching with regular expressions.
305 This allows you to write things like this:
309 ; CHECK: movhpd {{[0-9]+}}(%esp), {{%xmm[0-7]}}
311 In this case, any offset from the ESP register will be allowed, and any xmm
312 register will be allowed.
314 Because regular expressions are enclosed with double braces, they are
315 visually distinct, and you don't need to use escape characters within the double
316 braces like you would in C. In the rare case that you want to match double
317 braces explicitly from the input, you can use something ugly like
318 ``{{[{][{]}}`` as your pattern.
323 It is often useful to match a pattern and then verify that it occurs again
324 later in the file. For codegen tests, this can be useful to allow any register,
325 but verify that that register is used consistently later. To do this,
326 :program:`FileCheck` allows named variables to be defined and substituted into
327 patterns. Here is a simple example:
332 ; CHECK: notw [[REGISTER:%[a-z]+]]
333 ; CHECK: andw {{.*}}[[REGISTER]]
335 The first check line matches a regex ``%[a-z]+`` and captures it into the
336 variable ``REGISTER``. The second line verifies that whatever is in
337 ``REGISTER`` occurs later in the file after an "``andw``". :program:`FileCheck`
338 variable references are always contained in ``[[ ]]`` pairs, and their names can
339 be formed with the regex ``[a-zA-Z][a-zA-Z0-9]*``. If a colon follows the name,
340 then it is a definition of the variable; otherwise, it is a use.
342 :program:`FileCheck` variables can be defined multiple times, and uses always
343 get the latest value. Variables can also be used later on the same line they
344 were defined on. For example:
348 ; CHECK: op [[REG:r[0-9]+]], [[REG]]
350 Can be useful if you want the operands of ``op`` to be the same register,
351 and don't care exactly which register it is.
353 FileCheck Expressions
354 ~~~~~~~~~~~~~~~~~~~~~
356 Sometimes there's a need to verify output which refers line numbers of the
357 match file, e.g. when testing compiler diagnostics. This introduces a certain
358 fragility of the match file structure, as "``CHECK:``" lines contain absolute
359 line numbers in the same file, which have to be updated whenever line numbers
360 change due to text addition or deletion.
362 To support this case, FileCheck allows using ``[[@LINE]]``,
363 ``[[@LINE+<offset>]]``, ``[[@LINE-<offset>]]`` expressions in patterns. These
364 expressions expand to a number of the line where a pattern is located (with an
365 optional integer offset).
367 This way match patterns can be put near the relevant test lines and include
368 relative line number references, for example:
372 // CHECK: test.cpp:[[@LINE+4]]:6: error: expected ';' after top level declarator
373 // CHECK-NEXT: {{^int a}}
374 // CHECK-NEXT: {{^ \^}}
375 // CHECK-NEXT: {{^ ;}}