Provided by: llvm-9_9-2~ubuntu18.04.2_amd64 
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
different 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
Options are parsed from the environment variable FILECHECK_OPTS and from the command line.
-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.
--check-prefixes prefix1,prefix2,...
An alias of --check-prefix that allows multiple prefixes to be specified as a comma separated
list.
--input-file filename
File to check (defaults to stdin).
--match-full-lines
By default, FileCheck allows matches of anywhere on a line. This option will require all positive
matches to cover an entire line. Leading and trailing whitespace is ignored, unless
--strict-whitespace is also specified. (Note: negative matches from CHECK-NOT are not affected by
this option!)
Passing this option is equivalent to inserting {{^ *}} or {{^}} before, and {{ *$}} or {{$}} after
every positive check pattern.
--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 disables
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 without 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.
--dump-input <mode>
Dump input to stderr, adding annotations representing currently enabled diagnostics. Do this
either ‘always’, on ‘fail’, or ‘never’. Specify ‘help’ to explain the dump format and quit.
--dump-input-on-failure
When the check fails, dump all of the original input. This option is deprecated in favor of
–dump-input=fail.
--enable-var-scope
Enables scope for regex variables.
Variables with names that start with $ are considered global and remain set throughout the file.
All other variables get undefined after each encountered CHECK-LABEL.
-D<VAR=VALUE>
Sets a filecheck pattern variable VAR with value VALUE that can be used in CHECK: lines.
-D#<NUMVAR>=<VALUE EXPRESSION>
Sets a filecheck numeric variable NUMVAR to the result of evaluating <VALUE EXPRESSION> that can
be used in CHECK: lines. See section FileCheck Numeric Variables and Expressions for details on
the format and meaning of <VALUE EXPRESSION>.
-version
Show the version number of this program.
-v Print good directive pattern matches. However, if -input-dump=fail or -input-dump=always, add
those matches as input annotations instead.
-vv Print information helpful in diagnosing internal FileCheck issues, such as discarded overlapping
CHECK-DAG: matches, implicit EOF pattern matches, and CHECK-NOT: patterns that do not have
matches. Implies -v. However, if -input-dump=fail or -input-dump=always, just add that
information as input annotations instead.
--allow-deprecated-dag-overlap
Enable overlapping among matches in a group of consecutive CHECK-DAG: directives. This option is
deprecated and is only provided for convenience as old tests are migrated to the new
non-overlapping CHECK-DAG: implementation.
--color
Use colors in output (autodetected by default).
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 specified 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-SAME:” directive
Sometimes you want to match lines and would like to verify that matches happen on the same line as the
previous match. In this case, you can use “CHECK:” and “CHECK-SAME:” directives to specify this. If you
specified a custom check prefix, just use “<PREFIX>-SAME:”.
“CHECK-SAME:” is particularly powerful in conjunction with “CHECK-NOT:” (described below).
For example, the following works like you’d expect:
!0 = !DILocation(line: 5, scope: !1, inlinedAt: !2)
; CHECK: !DILocation(line: 5,
; CHECK-NOT: column:
; CHECK-SAME: scope: ![[SCOPE:[0-9]+]]
“CHECK-SAME:” directives reject the input if there are any newlines between it and the previous
directive. A “CHECK-SAME:” cannot be the first directive in a file.
The “CHECK-EMPTY:” directive
If you need to check that the next line has nothing on it, not even whitespace, you can use the
“CHECK-EMPTY:” directive.
declare void @foo()
declare void @bar()
; CHECK: foo
; CHECK-EMPTY:
; CHECK-NEXT: bar
Just like “CHECK-NEXT:” the directive will fail if there is more than one newline before it finds the
next blank line, and it 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
transformation, 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-COUNT:” directive
If you need to match multiple lines with the same pattern over and over again you can repeat a plain
CHECK: as many times as needed. If that looks too boring you can instead use a counted check
“CHECK-COUNT-<num>:”, where <num> is a positive decimal number. It will match the pattern exactly <num>
times, no more and no less. If you specified a custom check prefix, just use “<PREFIX>-COUNT-<num>:” for
the same effect. Here is a simple example:
Loop at depth 1
Loop at depth 1
Loop at depth 1
Loop at depth 1
Loop at depth 2
Loop at depth 3
; CHECK-COUNT-6: Loop at depth {{[0-9]+}}
; CHECK-NOT: Loop at depth {{[0-9]+}}
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
example, 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.
A CHECK-DAG: directive skips matches that overlap the matches of any preceding CHECK-DAG: directives in
the same CHECK-DAG: block. Not only is this non-overlapping behavior consistent with other directives,
but it’s also necessary to handle sets of non-unique strings or patterns. For example, the following
directives look for unordered log entries for two tasks in a parallel program, such as the OpenMP
runtime:
// CHECK-DAG: [[THREAD_ID:[0-9]+]]: task_begin
// CHECK-DAG: [[THREAD_ID]]: task_end
//
// CHECK-DAG: [[THREAD_ID:[0-9]+]]: task_begin
// CHECK-DAG: [[THREAD_ID]]: task_end
The second pair of directives is guaranteed not to match the same log entries as the first pair even
though the patterns are identical and even if the text of the log entries is identical because the thread
ID manages to be reused.
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. Conceptually, the
presence of CHECK-LABEL divides the input stream into separate blocks, each of which is processed
independently, preventing a CHECK: directive in one block matching a line in another block. If
--enable-var-scope is in effect, all local variables are cleared at the beginning of the 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 multiple 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 language: they must simply uniquely match a single line in the file being
verified.
CHECK-LABEL: directives cannot contain variable definitions or uses.
FileCheck Regex Matching Syntax
All FileCheck directives take a pattern to match. For most uses of FileCheck, fixed string matching is
perfectly sufficient. 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}}. FileCheck implements a POSIX regular expression matcher; it supports Extended POSIX
regular expressions (ERE). 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 String Substitution Blocks
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 supports string substitution blocks that allow string
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 string variable REGISTER. The
second line verifies that whatever is in REGISTER occurs later in the file after an “andw”. FileCheck
string substitution blocks are always contained in [[ ]] pairs, and string variable 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 substitution.
FileCheck variables can be defined multiple times, and substitutions always get the latest value.
Variables can also be substituted 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.
If --enable-var-scope is in effect, variables with names that start with $ are considered to be global.
All others variables are local. All local variables get undefined at the beginning of each CHECK-LABEL
block. Global variables are not affected by CHECK-LABEL. This makes it easier to ensure that individual
tests are not affected by variables set in preceding tests.
FileCheck Numeric Substitution Blocks
FileCheck also supports numeric substitution blocks that allow defining numeric variables and checking
for numeric values that satisfy a numeric expression constraint based on those variables via a numeric
substitution. This allows CHECK: directives to verify a numeric relation between two numbers, such as the
need for consecutive registers to be used.
The syntax to define a numeric variable is [[#<NUMVAR>:]] where <NUMVAR> is the name of the numeric
variable to define to the matching value.
For example:
; CHECK: mov r[[#REG:]], 42
would match mov r5, 42 and set REG to the value 5.
The syntax of a numeric substitution is [[#<expr>]] where <expr> is an expression. An expression is
recursively defined as:
• a numeric operand, or
• an expression followed by an operator and a numeric operand.
A numeric operand is a previously defined numeric variable, or an integer literal. The supported
operators are + and -. Spaces are accepted before, after and between any of these elements.
For example:
; CHECK: load r[[#REG:]], [r0]
; CHECK: load r[[#REG+1]], [r1]
The above example would match the text:
load r5, [r0]
load r6, [r1]
but would not match the text:
load r5, [r0]
load r7, [r1]
due to 7 being unequal to 5 + 1.
The --enable-var-scope option has the same effect on numeric variables as on string variables.
Important note: In its current implementation, an expression cannot use a numeric variable defined on the
same line.
FileCheck Pseudo Numeric Variables
Sometimes there’s a need to verify output that contains line numbers of the match file, e.g. when testing
compiler diagnostics. This introduces 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 expressions understand the @LINE pseudo numeric variable which evaluates
to the line number of the CHECK pattern where it is found.
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
To support legacy uses of @LINE as a special string variable, FileCheck also accepts the following uses
of @LINE with string substitution block syntax: [[@LINE]], [[@LINE+<offset>]] and [[@LINE-<offset>]]
without any spaces inside the brackets and where offset is an integer.
Matching Newline Characters
To match newline characters in regular expressions the character class [[:space:]] can be used. For
example, the following pattern:
// CHECK: DW_AT_location [DW_FORM_sec_offset] ([[DLOC:0x[0-9a-f]+]]){{[[:space:]].*}}"intd"
matches output of the form (from llvm-dwarfdump):
DW_AT_location [DW_FORM_sec_offset] (0x00000233)
DW_AT_name [DW_FORM_strp] ( .debug_str[0x000000c9] = "intd")
letting us set the FileCheck variable DLOC to the desired value 0x00000233, extracted from the line
immediately preceding “intd”.
AUTHOR
Maintained by the LLVM Team (https://llvm.org/).
COPYRIGHT
2003-2020, LLVM Project
9 2020-01-31 FILECHECK(1)