1FileCheck - Flexible pattern matching file verifier 2=================================================== 3 4SYNOPSIS 5-------- 6 7:program:`FileCheck` *match-filename* [*--check-prefix=XXX*] [*--strict-whitespace*] 8 9DESCRIPTION 10----------- 11 12:program:`FileCheck` reads two files (one from standard input, and one 13specified on the command line) and uses one to verify the other. This 14behavior is particularly useful for the testsuite, which wants to verify that 15the 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 17using :program:`grep`, but it is optimized for matching multiple different 18inputs in one file in a specific order. 19 20The ``match-filename`` file specifies the file that contains the patterns to 21match. The file to verify is always read from standard input. 22 23OPTIONS 24------- 25 26.. option:: -help 27 28 Print a summary of command line options. 29 30.. option:: --check-prefix prefix 31 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. 37 38.. option:: --input-file filename 39 40 File to check (defaults to stdin). 41 42.. option:: --strict-whitespace 43 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. 47 48.. option:: -version 49 50 Show the version number of this program. 51 52EXIT STATUS 53----------- 54 55If :program:`FileCheck` verifies that the file matches the expected contents, 56it exits with 0. Otherwise, if not, or if an error occurs, it will exit with a 57non-zero value. 58 59TUTORIAL 60-------- 61 62FileCheck is typically used from LLVM regression tests, being invoked on the RUN 63line of the test. A simple example of using FileCheck from a RUN line looks 64like this: 65 66.. code-block:: llvm 67 68 ; RUN: llvm-as < %s | llc -march=x86-64 | FileCheck %s 69 70This syntax says to pipe the current file ("``%s``") into ``llvm-as``, pipe 71that into ``llc``, then pipe the output of ``llc`` into ``FileCheck``. This 72means that FileCheck will be verifying its standard input (the llc output) 73against the filename argument specified (the original ``.ll`` file specified by 74"``%s``"). To see how this works, let's look at the rest of the ``.ll`` file 75(after the RUN line): 76 77.. code-block:: llvm 78 79 define void @sub1(i32* %p, i32 %v) { 80 entry: 81 ; CHECK: sub1: 82 ; CHECK: subl 83 %0 = tail call i32 @llvm.atomic.load.sub.i32.p0i32(i32* %p, i32 %v) 84 ret void 85 } 86 87 define void @inc4(i64* %p) { 88 entry: 89 ; CHECK: inc4: 90 ; CHECK: incq 91 %0 = tail call i64 @llvm.atomic.load.add.i64.p0i64(i64* %p, i64 1) 92 ret void 93 } 94 95Here you can see some "``CHECK:``" lines specified in comments. Now you can 96see how the file is piped into ``llvm-as``, then ``llc``, and the machine code 97output is what we are verifying. FileCheck checks the machine code output to 98verify that it matches what the "``CHECK:``" lines specify. 99 100The syntax of the "``CHECK:``" lines is very simple: they are fixed strings that 101must occur in order. FileCheck defaults to ignoring horizontal whitespace 102differences (e.g. a space is allowed to match a tab) but otherwise, the contents 103of the "``CHECK:``" line is required to match some thing in the test file exactly. 104 105One nice thing about FileCheck (compared to grep) is that it allows merging 106test cases together into logical groups. For example, because the test above 107is checking for the "``sub1:``" and "``inc4:``" labels, it will not match 108unless there is a "``subl``" in between those labels. If it existed somewhere 109else in the file, that would not count: "``grep subl``" matches if "``subl``" 110exists anywhere in the file. 111 112The FileCheck -check-prefix option 113~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 114 115The FileCheck :option:`-check-prefix` option allows multiple test 116configurations to be driven from one `.ll` file. This is useful in many 117circumstances, for example, testing different architectural variants with 118:program:`llc`. Here's a simple example: 119 120.. code-block:: llvm 121 122 ; RUN: llvm-as < %s | llc -mtriple=i686-apple-darwin9 -mattr=sse41 \ 123 ; RUN: | FileCheck %s -check-prefix=X32 124 ; RUN: llvm-as < %s | llc -mtriple=x86_64-apple-darwin9 -mattr=sse41 \ 125 ; RUN: | FileCheck %s -check-prefix=X64 126 127 define <4 x i32> @pinsrd_1(i32 %s, <4 x i32> %tmp) nounwind { 128 %tmp1 = insertelement <4 x i32>; %tmp, i32 %s, i32 1 129 ret <4 x i32> %tmp1 130 ; X32: pinsrd_1: 131 ; X32: pinsrd $1, 4(%esp), %xmm0 132 133 ; X64: pinsrd_1: 134 ; X64: pinsrd $1, %edi, %xmm0 135 } 136 137In this case, we're testing that we get the expected code generation with 138both 32-bit and 64-bit code generation. 139 140The "CHECK-NEXT:" directive 141~~~~~~~~~~~~~~~~~~~~~~~~~~~ 142 143Sometimes you want to match lines and would like to verify that matches 144happen on exactly consecutive lines with no other lines in between them. In 145this case, you can use "``CHECK:``" and "``CHECK-NEXT:``" directives to specify 146this. If you specified a custom check prefix, just use "``<PREFIX>-NEXT:``". 147For example, something like this works as you'd expect: 148 149.. code-block:: llvm 150 151 define void @t2(<2 x double>* %r, <2 x double>* %A, double %B) { 152 %tmp3 = load <2 x double>* %A, align 16 153 %tmp7 = insertelement <2 x double> undef, double %B, i32 0 154 %tmp9 = shufflevector <2 x double> %tmp3, 155 <2 x double> %tmp7, 156 <2 x i32> < i32 0, i32 2 > 157 store <2 x double> %tmp9, <2 x double>* %r, align 16 158 ret void 159 160 ; CHECK: t2: 161 ; CHECK: movl 8(%esp), %eax 162 ; CHECK-NEXT: movapd (%eax), %xmm0 163 ; CHECK-NEXT: movhpd 12(%esp), %xmm0 164 ; CHECK-NEXT: movl 4(%esp), %eax 165 ; CHECK-NEXT: movapd %xmm0, (%eax) 166 ; CHECK-NEXT: ret 167 } 168 169"``CHECK-NEXT:``" directives reject the input unless there is exactly one 170newline between it and the previous directive. A "``CHECK-NEXT:``" cannot be 171the first directive in a file. 172 173The "CHECK-NOT:" directive 174~~~~~~~~~~~~~~~~~~~~~~~~~~ 175 176The "``CHECK-NOT:``" directive is used to verify that a string doesn't occur 177between two matches (or before the first match, or after the last match). For 178example, to verify that a load is removed by a transformation, a test like this 179can be used: 180 181.. code-block:: llvm 182 183 define i8 @coerce_offset0(i32 %V, i32* %P) { 184 store i32 %V, i32* %P 185 186 %P2 = bitcast i32* %P to i8* 187 %P3 = getelementptr i8* %P2, i32 2 188 189 %A = load i8* %P3 190 ret i8 %A 191 ; CHECK: @coerce_offset0 192 ; CHECK-NOT: load 193 ; CHECK: ret i8 194 } 195 196FileCheck Pattern Matching Syntax 197~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 198 199The "``CHECK:``" and "``CHECK-NOT:``" directives both take a pattern to match. 200For most uses of FileCheck, fixed string matching is perfectly sufficient. For 201some things, a more flexible form of matching is desired. To support this, 202FileCheck allows you to specify regular expressions in matching strings, 203surrounded by double braces: ``{{yourregex}}``. Because we want to use fixed 204string matching for a majority of what we do, FileCheck has been designed to 205support mixing and matching fixed string matching with regular expressions. 206This allows you to write things like this: 207 208.. code-block:: llvm 209 210 ; CHECK: movhpd {{[0-9]+}}(%esp), {{%xmm[0-7]}} 211 212In this case, any offset from the ESP register will be allowed, and any xmm 213register will be allowed. 214 215Because regular expressions are enclosed with double braces, they are 216visually distinct, and you don't need to use escape characters within the double 217braces like you would in C. In the rare case that you want to match double 218braces explicitly from the input, you can use something ugly like 219``{{[{][{]}}`` as your pattern. 220 221FileCheck Variables 222~~~~~~~~~~~~~~~~~~~ 223 224It is often useful to match a pattern and then verify that it occurs again 225later in the file. For codegen tests, this can be useful to allow any register, 226but verify that that register is used consistently later. To do this, 227:program:`FileCheck` allows named variables to be defined and substituted into 228patterns. Here is a simple example: 229 230.. code-block:: llvm 231 232 ; CHECK: test5: 233 ; CHECK: notw [[REGISTER:%[a-z]+]] 234 ; CHECK: andw {{.*}}[[REGISTER]] 235 236The first check line matches a regex ``%[a-z]+`` and captures it into the 237variable ``REGISTER``. The second line verifies that whatever is in 238``REGISTER`` occurs later in the file after an "``andw``". :program:`FileCheck` 239variable references are always contained in ``[[ ]]`` pairs, and their names can 240be formed with the regex ``[a-zA-Z][a-zA-Z0-9]*``. If a colon follows the name, 241then it is a definition of the variable; otherwise, it is a use. 242 243:program:`FileCheck` variables can be defined multiple times, and uses always 244get the latest value. Variables can also be used later on the same line they 245were defined on. For example: 246 247.. code-block:: llvm 248 249 ; CHECK: op [[REG:r[0-9]+]], [[REG]] 250 251Can be useful if you want the operands of ``op`` to be the same register, 252and don't care exactly which register it is. 253 254FileCheck Expressions 255~~~~~~~~~~~~~~~~~~~~~ 256 257Sometimes there's a need to verify output which refers line numbers of the 258match file, e.g. when testing compiler diagnostics. This introduces a certain 259fragility of the match file structure, as "``CHECK:``" lines contain absolute 260line numbers in the same file, which have to be updated whenever line numbers 261change due to text addition or deletion. 262 263To support this case, FileCheck allows using ``[[@LINE]]``, 264``[[@LINE+<offset>]]``, ``[[@LINE-<offset>]]`` expressions in patterns. These 265expressions expand to a number of the line where a pattern is located (with an 266optional integer offset). 267 268This way match patterns can be put near the relevant test lines and include 269relative line number references, for example: 270 271.. code-block:: c++ 272 273 // CHECK: test.cpp:[[@LINE+4]]:6: error: expected ';' after top level declarator 274 // CHECK-NEXT: {{^int a}} 275 // CHECK-NEXT: {{^ \^}} 276 // CHECK-NEXT: {{^ ;}} 277 int a 278 279