FileCheck-3.5(1)



FILECHECK(1)                         LLVM                         FILECHECK(1)

NAME
       FileCheck - Flexible pattern matching file verifier

SYNOPSIS
       FileCheck match-filename [--check-prefix=XXX] [--strict-whitespace]

DESCRIPTION
       FileCheck  reads  two files (one from standard input, and one specified
       on the command line) and uses one to verify the other.   This  behavior
       is  particularly  useful  for the testsuite, which wants to verify that
       the output of some tool (e.g. llc) contains  the  expected  information
       (for  example,  a  movsd from esp or whatever is interesting).  This is
       similar to using grep, but it is optimized for matching  multiple  dif-
       ferent inputs in one file in a specific order.

       The  match-filename  file specifies the file that contains the patterns
       to match.  The file to verify is read from standard  input  unless  the
       --input-file option is used.

OPTIONS
       -help  Print a summary of command line options.

       --check-prefix prefix
              FileCheck  searches  the contents of match-filename for patterns
              to  match.   By  default,  these  patterns  are  prefixed   with
              "CHECK:".  If you'd like to use a different prefix (e.g. because
              the same input file  is  checking  multiple  different  tool  or
              options),  the --check-prefix argument allows you to specify one
              or more prefixes to match.  Multiple  prefixes  are  useful  for
              tests  which  might  change  for different run options, but most
              lines remain the same.

       --input-file filename
              File to check (defaults to stdin).

       --strict-whitespace
              By default, FileCheck canonicalizes input horizontal  whitespace
              (spaces and tabs) which causes it to ignore these differences (a
              space will match a tab).  The --strict-whitespace argument  dis-
              ables  this behavior. End-of-line sequences are canonicalized to
              UNIX-style \n in all modes.

       --implicit-check-not check-pattern
              Adds implicit negative checks for the specified patterns between
              positive  checks. The option allows writing stricter tests with-
              out stuffing them with CHECK-NOTs.

              For example, "--implicit-check-not warning:" can be useful  when
              testing diagnostic messages from tools that don't have an option
              similar to clang -verify. With this option FileCheck will verify
              that  input  does not contain warnings not covered by any CHECK:
              patterns.

       -version
              Show the version number of this program.

EXIT STATUS
       If FileCheck verifies that the file matches the expected  contents,  it
       exits  with  0.  Otherwise, if not, or if an error occurs, it will exit
       with a non-zero value.

TUTORIAL
       FileCheck is typically used from LLVM regression tests,  being  invoked
       on  the RUN line of the test.  A simple example of using FileCheck from
       a RUN line looks like this:

          ; RUN: llvm-as < %s | llc -march=x86-64 | FileCheck %s

       This syntax says to pipe the current file  ("%s")  into  llvm-as,  pipe
       that  into llc, then pipe the output of llc into FileCheck.  This means
       that FileCheck will be verifying its standard input  (the  llc  output)
       against  the  filename argument specified (the original .ll file speci-
       fied by "%s").  To see how this works, let's look at the  rest  of  the
       .ll file (after the RUN line):

          define void @sub1(i32* %p, i32 %v) {
          entry:
          ; CHECK: sub1:
          ; CHECK: subl
                  %0 = tail call i32 @llvm.atomic.load.sub.i32.p0i32(i32* %p, i32 %v)
                  ret void
          }

          define void @inc4(i64* %p) {
          entry:
          ; CHECK: inc4:
          ; CHECK: incq
                  %0 = tail call i64 @llvm.atomic.load.add.i64.p0i64(i64* %p, i64 1)
                  ret void
          }

       Here  you  can  see some "CHECK:" lines specified in comments.  Now you
       can see how the file is piped into llvm-as, then llc, and  the  machine
       code  output  is  what  we are verifying.  FileCheck checks the machine
       code output to verify that it matches what the "CHECK:" lines specify.

       The syntax of the "CHECK:" lines is very simple: they are fixed strings
       that  must  occur  in order.  FileCheck defaults to ignoring horizontal
       whitespace differences (e.g. a space is allowed to  match  a  tab)  but
       otherwise,  the contents of the "CHECK:" line is required to match some
       thing in the test file exactly.

       One nice thing about FileCheck (compared to grep)  is  that  it  allows
       merging  test cases together into logical groups.  For example, because
       the test above is checking for the "sub1:" and "inc4:" labels, it  will
       not  match  unless  there  is  a "subl" in between those labels.  If it
       existed somewhere else in the file, that would not count:  "grep  subl"
       matches if "subl" exists anywhere in the file.

   The FileCheck -check-prefix option
       The  FileCheck -check-prefix option allows multiple test configurations
       to be driven from one .ll file.  This is useful in many  circumstances,
       for example, testing different architectural variants with llc.  Here's
       a simple example:

          ; RUN: llvm-as < %s | llc -mtriple=i686-apple-darwin9 -mattr=sse41 \
          ; RUN:              | FileCheck %s -check-prefix=X32
          ; RUN: llvm-as < %s | llc -mtriple=x86_64-apple-darwin9 -mattr=sse41 \
          ; RUN:              | FileCheck %s -check-prefix=X64

          define <4 x i32> @pinsrd_1(i32 %s, <4 x i32> %tmp) nounwind {
                  %tmp1 = insertelement <4 x i32>; %tmp, i32 %s, i32 1
                  ret <4 x i32> %tmp1
          ; X32: pinsrd_1:
          ; X32:    pinsrd $1, 4(%esp), %xmm0

          ; X64: pinsrd_1:
          ; X64:    pinsrd $1, %edi, %xmm0
          }

       In this case, we're testing that we get the  expected  code  generation
       with both 32-bit and 64-bit code generation.

   The CHECK-NEXT: directive
       Sometimes you want to match lines and would like to verify that matches
       happen on exactly consecutive lines with  no  other  lines  in  between
       them.   In this case, you can use "CHECK:" and "CHECK-NEXT:" directives
       to specify this.  If you specified a  custom  check  prefix,  just  use
       "<PREFIX>-NEXT:".   For  example,  something  like  this works as you'd
       expect:

          define void @t2(<2 x double>* %r, <2 x double>* %A, double %B) {
               %tmp3 = load <2 x double>* %A, align 16
               %tmp7 = insertelement <2 x double> undef, double %B, i32 0
               %tmp9 = shufflevector <2 x double> %tmp3,
                                      <2 x double> %tmp7,
                                      <2 x i32> < i32 0, i32 2 >
               store <2 x double> %tmp9, <2 x double>* %r, align 16
               ret void

          ; CHECK:          t2:
          ; CHECK:             movl    8(%esp), %eax
          ; CHECK-NEXT:        movapd  (%eax), %xmm0
          ; CHECK-NEXT:        movhpd  12(%esp), %xmm0
          ; CHECK-NEXT:        movl    4(%esp), %eax
          ; CHECK-NEXT:        movapd  %xmm0, (%eax)
          ; CHECK-NEXT:        ret
          }

       "CHECK-NEXT:" directives reject the input unless there is  exactly  one
       newline  between it and the previous directive.  A "CHECK-NEXT:" cannot
       be the first directive in a file.

   The CHECK-NOT: directive
       The "CHECK-NOT:" directive is used to  verify  that  a  string  doesn't
       occur between two matches (or before the first match, or after the last
       match).  For example, to verify that a load is removed by a transforma-
       tion, a test like this can be used:

          define i8 @coerce_offset0(i32 %V, i32* %P) {
            store i32 %V, i32* %P

            %P2 = bitcast i32* %P to i8*
            %P3 = getelementptr i8* %P2, i32 2

            %A = load i8* %P3
            ret i8 %A
          ; CHECK: @coerce_offset0
          ; CHECK-NOT: load
          ; CHECK: ret i8
          }

   The CHECK-DAG: directive
       If  it's  necessary  to  match  strings  that don't occur in a strictly
       sequential order, "CHECK-DAG:" could be used to verify them between two
       matches (or before the first match, or after the last match). For exam-
       ple, clang emits vtable globals in reverse order. Using CHECK-DAG:,  we
       can keep the checks in the natural order:

          // RUN: %clang_cc1 %s -emit-llvm -o - | FileCheck %s

          struct Foo { virtual void method(); };
          Foo f;  // emit vtable
          // CHECK-DAG: @_ZTV3Foo =

          struct Bar { virtual void method(); };
          Bar b;
          // CHECK-DAG: @_ZTV3Bar =

       CHECK-NOT:  directives  could  be  mixed  with CHECK-DAG: directives to
       exclude strings between the surrounding  CHECK-DAG:  directives.  As  a
       result, the surrounding CHECK-DAG: directives cannot be reordered, i.e.
       all occurrences matching CHECK-DAG: before  CHECK-NOT:  must  not  fall
       behind occurrences matching CHECK-DAG: after CHECK-NOT:. For example,

          ; CHECK-DAG: BEFORE
          ; CHECK-NOT: NOT
          ; CHECK-DAG: AFTER

       This case will reject input strings where BEFORE occurs after AFTER.

       With  captured variables, CHECK-DAG: is able to match valid topological
       orderings of a DAG with edges from the definition of a variable to  its
       use.   It's  useful, e.g., when your test cases need to match different
       output sequences from the instruction scheduler. For example,

          ; CHECK-DAG: add [[REG1:r[0-9]+]], r1, r2
          ; CHECK-DAG: add [[REG2:r[0-9]+]], r3, r4
          ; CHECK:     mul r5, [[REG1]], [[REG2]]

       In this case, any order of that two add instructions will be allowed.

       If you are defining and using variables in the same  CHECK-DAG:  block,
       be aware that the definition rule can match after its use.

       So, for instance, the code below will pass:

          ; CHECK-DAG: vmov.32 [[REG2:d[0-9]+]][0]
          ; CHECK-DAG: vmov.32 [[REG2]][1]
          vmov.32 d0[1]
          vmov.32 d0[0]

       While this other code, will not:

          ; CHECK-DAG: vmov.32 [[REG2:d[0-9]+]][0]
          ; CHECK-DAG: vmov.32 [[REG2]][1]
          vmov.32 d1[1]
          vmov.32 d0[0]

       While this can be very useful, it's also dangerous, because in the case
       of register sequence, you must have a strong order (read before  write,
       copy  before  use,  etc).  If  the  definition your test is looking for
       doesn't match (because of a bug in the compiler), it may match  further
       away from the use, and mask real bugs away.

       In  those  cases, to enforce the order, use a non-DAG directive between
       DAG-blocks.

   The CHECK-LABEL: directive
       Sometimes in a file containing  multiple  tests  divided  into  logical
       blocks,  one  or  more  CHECK:  directives may inadvertently succeed by
       matching lines in a later block. While an error will usually eventually
       be  generated,  the check flagged as causing the error may not actually
       bear any relationship to the actual source of the problem.

       In  order  to  produce  better  error  messages  in  these  cases,  the
       "CHECK-LABEL:"  directive  can  be used. It is treated identically to a
       normal CHECK  directive  except  that  FileCheck  makes  an  additional
       assumption  that a line matched by the directive cannot also be matched
       by any other check present in match-filename; this is  intended  to  be
       used for lines containing labels or other unique identifiers. Conceptu-
       ally, the presence of CHECK-LABEL divides the input stream  into  sepa-
       rate  blocks,  each  of  which is processed independently, preventing a
       CHECK: directive in one block matching a line in  another  block.   For
       example,

          define %struct.C* @C_ctor_base(%struct.C* %this, i32 %x) {
          entry:
          ; CHECK-LABEL: C_ctor_base:
          ; CHECK: mov [[SAVETHIS:r[0-9]+]], r0
          ; CHECK: bl A_ctor_base
          ; CHECK: mov r0, [[SAVETHIS]]
            %0 = bitcast %struct.C* %this to %struct.A*
            %call = tail call %struct.A* @A_ctor_base(%struct.A* %0)
            %1 = bitcast %struct.C* %this to %struct.B*
            %call2 = tail call %struct.B* @B_ctor_base(%struct.B* %1, i32 %x)
            ret %struct.C* %this
          }

          define %struct.D* @D_ctor_base(%struct.D* %this, i32 %x) {
          entry:
          ; CHECK-LABEL: D_ctor_base:

       The  use of CHECK-LABEL: directives in this case ensures that the three
       CHECK: directives only accept lines corresponding to the  body  of  the
       @C_ctor_base  function, even if the patterns match lines found later in
       the file. Furthermore, if one of these three  CHECK:  directives  fail,
       FileCheck will recover by continuing to the next block, allowing multi-
       ple test failures to be detected in a single invocation.

       There is no requirement that CHECK-LABEL:  directives  contain  strings
       that  correspond  to actual syntactic labels in a source or output lan-
       guage: they must simply uniquely match a single line in the file  being
       verified.

       CHECK-LABEL: directives cannot contain variable definitions or uses.

   FileCheck Pattern Matching Syntax
       The  "CHECK:" and "CHECK-NOT:" directives both take a pattern to match.
       For most uses of FileCheck, fixed string matching is  perfectly  suffi-
       cient.   For  some things, a more flexible form of matching is desired.
       To support this, FileCheck allows you to specify regular expressions in
       matching  strings, surrounded by double braces: {{yourregex}}.  Because
       we want to use fixed string matching for a  majority  of  what  we  do,
       FileCheck has been designed to support mixing and matching fixed string
       matching with regular expressions.  This allows  you  to  write  things
       like this:

          ; CHECK: movhpd      {{[0-9]+}}(%esp), {{%xmm[0-7]}}

       In this case, any offset from the ESP register will be allowed, and any
       xmm register will be allowed.

       Because regular expressions are enclosed with double braces,  they  are
       visually  distinct,  and you don't need to use escape characters within
       the double braces like you would in C.  In the rare case that you  want
       to match double braces explicitly from the input, you can use something
       ugly like {{[{][{]}} as your pattern.

   FileCheck Variables
       It is often useful to match a pattern and then verify  that  it  occurs
       again  later  in  the  file.   For codegen tests, this can be useful to
       allow any register, but verify that that register is used  consistently
       later.   To do this, FileCheck allows named variables to be defined and
       substituted into patterns.  Here is a simple example:

          ; CHECK: test5:
          ; CHECK:    notw     [[REGISTER:%[a-z]+]]
          ; CHECK:    andw     {{.*}}[[REGISTER]]

       The first check line matches a regex %[a-z]+ and captures it  into  the
       variable REGISTER.  The second line verifies that whatever is in REGIS-
       TER occurs later in the file after an "andw".  FileCheck variable  ref-
       erences  are  always  contained  in [[ ]] pairs, and their names can be
       formed with the regex [a-zA-Z][a-zA-Z0-9]*.  If  a  colon  follows  the
       name, then it is a definition of the variable; otherwise, it is a use.

       FileCheck  variables can be defined multiple times, and uses always get
       the latest value.  Variables can also be used later on  the  same  line
       they were defined on. For example:

          ; CHECK: op [[REG:r[0-9]+]], [[REG]]

       Can  be  useful if you want the operands of op to be the same register,
       and don't care exactly which register it is.

   FileCheck Expressions
       Sometimes there's a need to verify output which refers line numbers  of
       the  match  file,  e.g. when testing compiler diagnostics.  This intro-
       duces a certain fragility of the  match  file  structure,  as  "CHECK:"
       lines  contain absolute line numbers in the same file, which have to be
       updated whenever line numbers change due to text addition or deletion.

       To support this case, FileCheck allows using  [[@LINE]],  [[@LINE+<off-
       set>]],  [[@LINE-<offset>]]  expressions in patterns. These expressions
       expand to a number of the line where a  pattern  is  located  (with  an
       optional integer offset).

       This  way  match  patterns  can be put near the relevant test lines and
       include relative line number references, for example:

          // CHECK: test.cpp:[[@LINE+4]]:6: error: expected ';' after top level declarator
          // CHECK-NEXT: {{^int a}}
          // CHECK-NEXT: {{^     \^}}
          // CHECK-NEXT: {{^     ;}}
          int a

AUTHOR
       Maintained by The LLVM Team (http://llvm.org/).

COPYRIGHT
       2003-2016, LLVM Project

3.5                               2016-10-07                      FILECHECK(1)

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