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. End-of-line 47 sequences are canonicalized to UNIX-style ``\n`` in all modes. 48 49.. option:: -version 50 51 Show the version number of this program. 52 53EXIT STATUS 54----------- 55 56If :program:`FileCheck` verifies that the file matches the expected contents, 57it exits with 0. Otherwise, if not, or if an error occurs, it will exit with a 58non-zero value. 59 60TUTORIAL 61-------- 62 63FileCheck is typically used from LLVM regression tests, being invoked on the RUN 64line of the test. A simple example of using FileCheck from a RUN line looks 65like this: 66 67.. code-block:: llvm 68 69 ; RUN: llvm-as < %s | llc -march=x86-64 | FileCheck %s 70 71This syntax says to pipe the current file ("``%s``") into ``llvm-as``, pipe 72that into ``llc``, then pipe the output of ``llc`` into ``FileCheck``. This 73means that FileCheck will be verifying its standard input (the llc output) 74against 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 76(after the RUN line): 77 78.. code-block:: llvm 79 80 define void @sub1(i32* %p, i32 %v) { 81 entry: 82 ; CHECK: sub1: 83 ; CHECK: subl 84 %0 = tail call i32 @llvm.atomic.load.sub.i32.p0i32(i32* %p, i32 %v) 85 ret void 86 } 87 88 define void @inc4(i64* %p) { 89 entry: 90 ; CHECK: inc4: 91 ; CHECK: incq 92 %0 = tail call i64 @llvm.atomic.load.add.i64.p0i64(i64* %p, i64 1) 93 ret void 94 } 95 96Here you can see some "``CHECK:``" lines specified in comments. Now you can 97see how the file is piped into ``llvm-as``, then ``llc``, and the machine code 98output is what we are verifying. FileCheck checks the machine code output to 99verify that it matches what the "``CHECK:``" lines specify. 100 101The syntax of the "``CHECK:``" lines is very simple: they are fixed strings that 102must occur in order. FileCheck defaults to ignoring horizontal whitespace 103differences (e.g. a space is allowed to match a tab) but otherwise, the contents 104of the "``CHECK:``" line is required to match some thing in the test file exactly. 105 106One nice thing about FileCheck (compared to grep) is that it allows merging 107test cases together into logical groups. For example, because the test above 108is checking for the "``sub1:``" and "``inc4:``" labels, it will not match 109unless there is a "``subl``" in between those labels. If it existed somewhere 110else in the file, that would not count: "``grep subl``" matches if "``subl``" 111exists anywhere in the file. 112 113The FileCheck -check-prefix option 114~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 115 116The FileCheck :option:`-check-prefix` option allows multiple test 117configurations to be driven from one `.ll` file. This is useful in many 118circumstances, for example, testing different architectural variants with 119:program:`llc`. Here's a simple example: 120 121.. code-block:: llvm 122 123 ; 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 127 128 define <4 x i32> @pinsrd_1(i32 %s, <4 x i32> %tmp) nounwind { 129 %tmp1 = insertelement <4 x i32>; %tmp, i32 %s, i32 1 130 ret <4 x i32> %tmp1 131 ; X32: pinsrd_1: 132 ; X32: pinsrd $1, 4(%esp), %xmm0 133 134 ; X64: pinsrd_1: 135 ; X64: pinsrd $1, %edi, %xmm0 136 } 137 138In this case, we're testing that we get the expected code generation with 139both 32-bit and 64-bit code generation. 140 141The "CHECK-NEXT:" directive 142~~~~~~~~~~~~~~~~~~~~~~~~~~~ 143 144Sometimes you want to match lines and would like to verify that matches 145happen on exactly consecutive lines with no other lines in between them. In 146this case, you can use "``CHECK:``" and "``CHECK-NEXT:``" directives to specify 147this. If you specified a custom check prefix, just use "``<PREFIX>-NEXT:``". 148For example, something like this works as you'd expect: 149 150.. code-block:: llvm 151 152 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, 156 <2 x double> %tmp7, 157 <2 x i32> < i32 0, i32 2 > 158 store <2 x double> %tmp9, <2 x double>* %r, align 16 159 ret void 160 161 ; CHECK: t2: 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) 167 ; CHECK-NEXT: ret 168 } 169 170"``CHECK-NEXT:``" directives reject the input unless there is exactly one 171newline between it and the previous directive. A "``CHECK-NEXT:``" cannot be 172the first directive in a file. 173 174The "CHECK-NOT:" directive 175~~~~~~~~~~~~~~~~~~~~~~~~~~ 176 177The "``CHECK-NOT:``" directive is used to verify that a string doesn't occur 178between two matches (or before the first match, or after the last match). For 179example, to verify that a load is removed by a transformation, a test like this 180can be used: 181 182.. code-block:: llvm 183 184 define i8 @coerce_offset0(i32 %V, i32* %P) { 185 store i32 %V, i32* %P 186 187 %P2 = bitcast i32* %P to i8* 188 %P3 = getelementptr i8* %P2, i32 2 189 190 %A = load i8* %P3 191 ret i8 %A 192 ; CHECK: @coerce_offset0 193 ; CHECK-NOT: load 194 ; CHECK: ret i8 195 } 196 197The "CHECK-DAG:" directive 198~~~~~~~~~~~~~~~~~~~~~~~~~~ 199 200If it's necessary to match strings that don't occur in a strictly sequential 201order, "``CHECK-DAG:``" could be used to verify them between two matches (or 202before the first match, or after the last match). For example, clang emits 203vtable globals in reverse order. Using ``CHECK-DAG:``, we can keep the checks 204in the natural order: 205 206.. code-block:: c++ 207 208 // RUN: %clang_cc1 %s -emit-llvm -o - | FileCheck %s 209 210 struct Foo { virtual void method(); }; 211 Foo f; // emit vtable 212 // CHECK-DAG: @_ZTV3Foo = 213 214 struct Bar { virtual void method(); }; 215 Bar b; 216 // CHECK-DAG: @_ZTV3Bar = 217 218 219With captured variables, ``CHECK-DAG:`` is able to match valid topological 220orderings of a DAG with edges from the definition of a variable to its use. 221It's useful, e.g., when your test cases need to match different output 222sequences from the instruction scheduler. For example, 223 224.. code-block:: llvm 225 226 ; 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]] 229 230In this case, any order of that two ``add`` instructions will be allowed. 231 232``CHECK-NOT:`` directives could be mixed with ``CHECK-DAG:`` directives to 233exclude strings between the surrounding ``CHECK-DAG:`` directives. As a result, 234the surrounding ``CHECK-DAG:`` directives cannot be reordered, i.e. all 235occurrences matching ``CHECK-DAG:`` before ``CHECK-NOT:`` must not fall behind 236occurrences matching ``CHECK-DAG:`` after ``CHECK-NOT:``. For example, 237 238.. code-block:: llvm 239 240 ; CHECK-DAG: BEFORE 241 ; CHECK-NOT: NOT 242 ; CHECK-DAG: AFTER 243 244This case will reject input strings where ``BEFORE`` occurs after ``AFTER``. 245 246FileCheck Pattern Matching Syntax 247~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 248 249The "``CHECK:``" and "``CHECK-NOT:``" directives both take a pattern to match. 250For most uses of FileCheck, fixed string matching is perfectly sufficient. For 251some things, a more flexible form of matching is desired. To support this, 252FileCheck allows you to specify regular expressions in matching strings, 253surrounded by double braces: ``{{yourregex}}``. Because we want to use fixed 254string matching for a majority of what we do, FileCheck has been designed to 255support mixing and matching fixed string matching with regular expressions. 256This allows you to write things like this: 257 258.. code-block:: llvm 259 260 ; CHECK: movhpd {{[0-9]+}}(%esp), {{%xmm[0-7]}} 261 262In this case, any offset from the ESP register will be allowed, and any xmm 263register will be allowed. 264 265Because regular expressions are enclosed with double braces, they are 266visually distinct, and you don't need to use escape characters within the double 267braces like you would in C. In the rare case that you want to match double 268braces explicitly from the input, you can use something ugly like 269``{{[{][{]}}`` as your pattern. 270 271FileCheck Variables 272~~~~~~~~~~~~~~~~~~~ 273 274It is often useful to match a pattern and then verify that it occurs again 275later in the file. For codegen tests, this can be useful to allow any register, 276but verify that that register is used consistently later. To do this, 277:program:`FileCheck` allows named variables to be defined and substituted into 278patterns. Here is a simple example: 279 280.. code-block:: llvm 281 282 ; CHECK: test5: 283 ; CHECK: notw [[REGISTER:%[a-z]+]] 284 ; CHECK: andw {{.*}}[[REGISTER]] 285 286The first check line matches a regex ``%[a-z]+`` and captures it into the 287variable ``REGISTER``. The second line verifies that whatever is in 288``REGISTER`` occurs later in the file after an "``andw``". :program:`FileCheck` 289variable references are always contained in ``[[ ]]`` pairs, and their names can 290be formed with the regex ``[a-zA-Z][a-zA-Z0-9]*``. If a colon follows the name, 291then it is a definition of the variable; otherwise, it is a use. 292 293:program:`FileCheck` variables can be defined multiple times, and uses always 294get the latest value. Variables can also be used later on the same line they 295were defined on. For example: 296 297.. code-block:: llvm 298 299 ; CHECK: op [[REG:r[0-9]+]], [[REG]] 300 301Can be useful if you want the operands of ``op`` to be the same register, 302and don't care exactly which register it is. 303 304FileCheck Expressions 305~~~~~~~~~~~~~~~~~~~~~ 306 307Sometimes there's a need to verify output which refers line numbers of the 308match file, e.g. when testing compiler diagnostics. This introduces a certain 309fragility of the match file structure, as "``CHECK:``" lines contain absolute 310line numbers in the same file, which have to be updated whenever line numbers 311change due to text addition or deletion. 312 313To support this case, FileCheck allows using ``[[@LINE]]``, 314``[[@LINE+<offset>]]``, ``[[@LINE-<offset>]]`` expressions in patterns. These 315expressions expand to a number of the line where a pattern is located (with an 316optional integer offset). 317 318This way match patterns can be put near the relevant test lines and include 319relative line number references, for example: 320 321.. code-block:: c++ 322 323 // CHECK: test.cpp:[[@LINE+4]]:6: error: expected ';' after top level declarator 324 // CHECK-NEXT: {{^int a}} 325 // CHECK-NEXT: {{^ \^}} 326 // CHECK-NEXT: {{^ ;}} 327 int a 328 329