1 FileCheck - Flexible pattern matching file verifier
2 ===================================================
9 **FileCheck** *match-filename* [*--check-prefix=XXX*] [*--strict-whitespace*]
16 **FileCheck** reads two files (one from standard input, and one specified on the
17 command line) and uses one to verify the other. This behavior is particularly
18 useful for the testsuite, which wants to verify that the output of some tool
19 (e.g. llc) contains the expected information (for example, a movsd from esp or
20 whatever is interesting). This is similar to using grep, but it is optimized
21 for matching multiple different inputs in one file in a specific order.
23 The *match-filename* file specifies the file that contains the patterns to
24 match. The file to verify is always read from standard input.
34 Print a summary of command line options.
38 **--check-prefix** *prefix*
40 FileCheck searches the contents of *match-filename* for patterns to match. By
41 default, these patterns are prefixed with "CHECK:". If you'd like to use a
42 different prefix (e.g. because the same input file is checking multiple
43 different tool or options), the **--check-prefix** argument allows you to specify
44 a specific prefix to match.
48 **--input-file** *filename*
50 File to check (defaults to stdin).
53 **--strict-whitespace**
55 By default, FileCheck canonicalizes input horizontal whitespace (spaces and
56 tabs) which causes it to ignore these differences (a space will match a tab).
57 The --strict-whitespace argument disables this behavior.
63 Show the version number of this program.
72 If **FileCheck** verifies that the file matches the expected contents, it exits
73 with 0. Otherwise, if not, or if an error occurs, it will exit with a non-zero
81 FileCheck is typically used from LLVM regression tests, being invoked on the RUN
82 line of the test. A simple example of using FileCheck from a RUN line looks
88 ; RUN: llvm-as < %s | llc -march=x86-64 | FileCheck %s
91 This syntax says to pipe the current file ("%s") into llvm-as, pipe that into
92 llc, then pipe the output of llc into FileCheck. This means that FileCheck will
93 be verifying its standard input (the llc output) against the filename argument
94 specified (the original .ll file specified by "%s"). To see how this works,
95 let's look at the rest of the .ll file (after the RUN line):
100 define void @sub1(i32* %p, i32 %v) {
104 %0 = tail call i32 @llvm.atomic.load.sub.i32.p0i32(i32* %p, i32 %v)
108 define void @inc4(i64* %p) {
112 %0 = tail call i64 @llvm.atomic.load.add.i64.p0i64(i64* %p, i64 1)
117 Here you can see some "CHECK:" lines specified in comments. Now you can see
118 how the file is piped into llvm-as, then llc, and the machine code output is
119 what we are verifying. FileCheck checks the machine code output to verify that
120 it matches what the "CHECK:" lines specify.
122 The syntax of the CHECK: lines is very simple: they are fixed strings that
123 must occur in order. FileCheck defaults to ignoring horizontal whitespace
124 differences (e.g. a space is allowed to match a tab) but otherwise, the contents
125 of the CHECK: line is required to match some thing in the test file exactly.
127 One nice thing about FileCheck (compared to grep) is that it allows merging
128 test cases together into logical groups. For example, because the test above
129 is checking for the "sub1:" and "inc4:" labels, it will not match unless there
130 is a "subl" in between those labels. If it existed somewhere else in the file,
131 that would not count: "grep subl" matches if subl exists anywhere in the
134 The FileCheck -check-prefix option
135 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
138 The FileCheck -check-prefix option allows multiple test configurations to be
139 driven from one .ll file. This is useful in many circumstances, for example,
140 testing different architectural variants with llc. Here's a simple example:
145 ; RUN: llvm-as < %s | llc -mtriple=i686-apple-darwin9 -mattr=sse41 \
146 ; RUN: | FileCheck %s -check-prefix=X32
147 ; RUN: llvm-as < %s | llc -mtriple=x86_64-apple-darwin9 -mattr=sse41 \
148 ; RUN: | FileCheck %s -check-prefix=X64
150 define <4 x i32> @pinsrd_1(i32 %s, <4 x i32> %tmp) nounwind {
151 %tmp1 = insertelement <4 x i32>; %tmp, i32 %s, i32 1
154 ; X32: pinsrd $1, 4(%esp), %xmm0
157 ; X64: pinsrd $1, %edi, %xmm0
161 In this case, we're testing that we get the expected code generation with
162 both 32-bit and 64-bit code generation.
165 The "CHECK-NEXT:" directive
166 ~~~~~~~~~~~~~~~~~~~~~~~~~~~
169 Sometimes you want to match lines and would like to verify that matches
170 happen on exactly consecutive lines with no other lines in between them. In
171 this case, you can use CHECK: and CHECK-NEXT: directives to specify this. If
172 you specified a custom check prefix, just use "<PREFIX>-NEXT:". For
173 example, something like this works as you'd expect:
178 define void @t2(<2 x double>* %r, <2 x double>* %A, double %B) {
179 %tmp3 = load <2 x double>* %A, align 16
180 %tmp7 = insertelement <2 x double> undef, double %B, i32 0
181 %tmp9 = shufflevector <2 x double> %tmp3,
183 <2 x i32> < i32 0, i32 2 >
184 store <2 x double> %tmp9, <2 x double>* %r, align 16
188 ; CHECK: movl 8(%esp), %eax
189 ; CHECK-NEXT: movapd (%eax), %xmm0
190 ; CHECK-NEXT: movhpd 12(%esp), %xmm0
191 ; CHECK-NEXT: movl 4(%esp), %eax
192 ; CHECK-NEXT: movapd %xmm0, (%eax)
197 CHECK-NEXT: directives reject the input unless there is exactly one newline
198 between it an the previous directive. A CHECK-NEXT cannot be the first
202 The "CHECK-NOT:" directive
203 ~~~~~~~~~~~~~~~~~~~~~~~~~~
206 The CHECK-NOT: directive is used to verify that a string doesn't occur
207 between two matches (or before the first match, or after the last match). For
208 example, to verify that a load is removed by a transformation, a test like this
214 define i8 @coerce_offset0(i32 %V, i32* %P) {
215 store i32 %V, i32* %P
217 %P2 = bitcast i32* %P to i8*
218 %P3 = getelementptr i8* %P2, i32 2
222 ; CHECK: @coerce_offset0
229 FileCheck Pattern Matching Syntax
230 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
233 The CHECK: and CHECK-NOT: directives both take a pattern to match. For most
234 uses of FileCheck, fixed string matching is perfectly sufficient. For some
235 things, a more flexible form of matching is desired. To support this, FileCheck
236 allows you to specify regular expressions in matching strings, surrounded by
237 double braces: **{{yourregex}}**. Because we want to use fixed string
238 matching for a majority of what we do, FileCheck has been designed to support
239 mixing and matching fixed string matching with regular expressions. This allows
240 you to write things like this:
245 ; CHECK: movhpd {{[0-9]+}}(%esp), {{%xmm[0-7]}}
248 In this case, any offset from the ESP register will be allowed, and any xmm
249 register will be allowed.
251 Because regular expressions are enclosed with double braces, they are
252 visually distinct, and you don't need to use escape characters within the double
253 braces like you would in C. In the rare case that you want to match double
254 braces explicitly from the input, you can use something ugly like
255 **{{[{][{]}}** as your pattern.
262 It is often useful to match a pattern and then verify that it occurs again
263 later in the file. For codegen tests, this can be useful to allow any register,
264 but verify that that register is used consistently later. To do this, FileCheck
265 allows named variables to be defined and substituted into patterns. Here is a
272 ; CHECK: notw [[REGISTER:%[a-z]+]]
273 ; CHECK: andw {{.*}}[[REGISTER]]
276 The first check line matches a regex (**%[a-z]+**) and captures it into
277 the variable "REGISTER". The second line verifies that whatever is in REGISTER
278 occurs later in the file after an "andw". FileCheck variable references are
279 always contained in **[[ ]]** pairs, and their names can be formed with the
280 regex **[a-zA-Z][a-zA-Z0-9]***. If a colon follows the name, then it is a
281 definition of the variable; otherwise, it is a use.
283 FileCheck variables can be defined multiple times, and uses always get the
284 latest value. Note that variables are all read at the start of a "CHECK" line
285 and are all defined at the end. This means that if you have something like
286 "**CHECK: [[XYZ:.\\*]]x[[XYZ]]**", the check line will read the previous
287 value of the XYZ variable and define a new one after the match is performed. If
288 you need to do something like this you can probably take advantage of the fact
289 that FileCheck is not actually line-oriented when it matches, this allows you to
290 define two separate CHECK lines that match on the same line.