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 **--strict-whitespace**
50 By default, FileCheck canonicalizes input horizontal whitespace (spaces and
51 tabs) which causes it to ignore these differences (a space will match a tab).
52 The --strict-whitespace argument disables this behavior.
58 Show the version number of this program.
67 If **FileCheck** verifies that the file matches the expected contents, it exits
68 with 0. Otherwise, if not, or if an error occurs, it will exit with a non-zero
76 FileCheck is typically used from LLVM regression tests, being invoked on the RUN
77 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
86 This syntax says to pipe the current file ("%s") into llvm-as, pipe that into
87 llc, then pipe the output of llc into FileCheck. This means that FileCheck will
88 be verifying its standard input (the llc output) against the filename argument
89 specified (the original .ll file specified by "%s"). To see how this works,
90 let's look at the rest of the .ll file (after the RUN line):
95 define void @sub1(i32* %p, i32 %v) {
99 %0 = tail call i32 @llvm.atomic.load.sub.i32.p0i32(i32* %p, i32 %v)
103 define void @inc4(i64* %p) {
107 %0 = tail call i64 @llvm.atomic.load.add.i64.p0i64(i64* %p, i64 1)
112 Here you can see some "CHECK:" lines specified in comments. Now you can see
113 how the file is piped into llvm-as, then llc, and the machine code output is
114 what we are verifying. FileCheck checks the machine code output to verify that
115 it matches what the "CHECK:" lines specify.
117 The syntax of the CHECK: lines is very simple: they are fixed strings that
118 must occur in order. FileCheck defaults to ignoring horizontal whitespace
119 differences (e.g. a space is allowed to match a tab) but otherwise, the contents
120 of the CHECK: line is required to match some thing in the test file exactly.
122 One nice thing about FileCheck (compared to grep) is that it allows merging
123 test cases together into logical groups. For example, because the test above
124 is checking for the "sub1:" and "inc4:" labels, it will not match unless there
125 is a "subl" in between those labels. If it existed somewhere else in the file,
126 that would not count: "grep subl" matches if subl exists anywhere in the
129 The FileCheck -check-prefix option
130 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
133 The FileCheck -check-prefix option allows multiple test configurations to be
134 driven from one .ll file. This is useful in many circumstances, for example,
135 testing different architectural variants with llc. Here's a simple example:
140 ; RUN: llvm-as < %s | llc -mtriple=i686-apple-darwin9 -mattr=sse41 \
141 ; RUN: | FileCheck %s -check-prefix=X32
142 ; RUN: llvm-as < %s | llc -mtriple=x86_64-apple-darwin9 -mattr=sse41 \
143 ; RUN: | FileCheck %s -check-prefix=X64
145 define <4 x i32> @pinsrd_1(i32 %s, <4 x i32> %tmp) nounwind {
146 %tmp1 = insertelement <4 x i32>; %tmp, i32 %s, i32 1
149 ; X32: pinsrd $1, 4(%esp), %xmm0
152 ; X64: pinsrd $1, %edi, %xmm0
156 In this case, we're testing that we get the expected code generation with
157 both 32-bit and 64-bit code generation.
160 The "CHECK-NEXT:" directive
161 ~~~~~~~~~~~~~~~~~~~~~~~~~~~
164 Sometimes you want to match lines and would like to verify that matches
165 happen on exactly consecutive lines with no other lines in between them. In
166 this case, you can use CHECK: and CHECK-NEXT: directives to specify this. If
167 you specified a custom check prefix, just use "<PREFIX>-NEXT:". For
168 example, something like this works as you'd expect:
173 define void @t2(<2 x double>* %r, <2 x double>* %A, double %B) {
174 %tmp3 = load <2 x double>* %A, align 16
175 %tmp7 = insertelement <2 x double> undef, double %B, i32 0
176 %tmp9 = shufflevector <2 x double> %tmp3,
178 <2 x i32> < i32 0, i32 2 >
179 store <2 x double> %tmp9, <2 x double>* %r, align 16
183 ; CHECK: movl 8(%esp), %eax
184 ; CHECK-NEXT: movapd (%eax), %xmm0
185 ; CHECK-NEXT: movhpd 12(%esp), %xmm0
186 ; CHECK-NEXT: movl 4(%esp), %eax
187 ; CHECK-NEXT: movapd %xmm0, (%eax)
192 CHECK-NEXT: directives reject the input unless there is exactly one newline
193 between it an the previous directive. A CHECK-NEXT cannot be the first
197 The "CHECK-NOT:" directive
198 ~~~~~~~~~~~~~~~~~~~~~~~~~~
201 The CHECK-NOT: directive is used to verify that a string doesn't occur
202 between two matches (or before the first match, or after the last match). For
203 example, to verify that a load is removed by a transformation, a test like this
209 define i8 @coerce_offset0(i32 %V, i32* %P) {
210 store i32 %V, i32* %P
212 %P2 = bitcast i32* %P to i8*
213 %P3 = getelementptr i8* %P2, i32 2
217 ; CHECK: @coerce_offset0
224 FileCheck Pattern Matching Syntax
225 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
228 The CHECK: and CHECK-NOT: directives both take a pattern to match. For most
229 uses of FileCheck, fixed string matching is perfectly sufficient. For some
230 things, a more flexible form of matching is desired. To support this, FileCheck
231 allows you to specify regular expressions in matching strings, surrounded by
232 double braces: **{{yourregex}}**. Because we want to use fixed string
233 matching for a majority of what we do, FileCheck has been designed to support
234 mixing and matching fixed string matching with regular expressions. This allows
235 you to write things like this:
240 ; CHECK: movhpd {{[0-9]+}}(%esp), {{%xmm[0-7]}}
243 In this case, any offset from the ESP register will be allowed, and any xmm
244 register will be allowed.
246 Because regular expressions are enclosed with double braces, they are
247 visually distinct, and you don't need to use escape characters within the double
248 braces like you would in C. In the rare case that you want to match double
249 braces explicitly from the input, you can use something ugly like
250 **{{[{][{]}}** as your pattern.
257 It is often useful to match a pattern and then verify that it occurs again
258 later in the file. For codegen tests, this can be useful to allow any register,
259 but verify that that register is used consistently later. To do this, FileCheck
260 allows named variables to be defined and substituted into patterns. Here is a
267 ; CHECK: notw [[REGISTER:%[a-z]+]]
268 ; CHECK: andw {{.*}}[[REGISTER]]
271 The first check line matches a regex (**%[a-z]+**) and captures it into
272 the variable "REGISTER". The second line verifies that whatever is in REGISTER
273 occurs later in the file after an "andw". FileCheck variable references are
274 always contained in **[[ ]]** pairs, are named, and their names can be
275 name, then it is a definition of the variable, if not, it is a use.
277 FileCheck variables can be defined multiple times, and uses always get the
278 latest value. Note that variables are all read at the start of a "CHECK" line
279 and are all defined at the end. This means that if you have something like
280 "**CHECK: [[XYZ:.\\*]]x[[XYZ]]**", the check line will read the previous
281 value of the XYZ variable and define a new one after the match is performed. If
282 you need to do something like this you can probably take advantage of the fact
283 that FileCheck is not actually line-oriented when it matches, this allows you to
284 define two separate CHECK lines that match on the same line.