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
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 op-
tions), the --check-prefix argument allows you to specify (with-
out the trailing “:”) 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.
FileCheck does not permit duplicate prefixes, even if one is a
check prefix and one is a comment prefix (see --comment-prefixes
below).
--check-prefixes prefix1,prefix2,...
An alias of --check-prefix that allows multiple prefixes to be
specified as a comma separated list.
--comment-prefixes prefix1,prefix2,...
By default, FileCheck ignores any occurrence in match-filename
of any check prefix if it is preceded on the same line by “COM:”
or “RUN:”. See the section The “COM:” directive for usage de-
tails.
These default comment prefixes can be overridden by
--comment-prefixes if they are not appropriate for your testing
environment. However, doing so is not recommended in LLVM’s
LIT-based test suites, which should be easier to maintain if
they all follow a consistent comment style. In that case, con-
sider proposing a change to the default comment prefixes in-
stead.
--allow-unused-prefixes
This option controls the behavior when using more than one pre-
fix as specified by --check-prefix or --check-prefixes, and some
of these prefixes are missing in the test file. If true, this is
allowed, if false, FileCheck will report an error, listing the
missing prefixes. The default value is false.
--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 dis-
ables this behavior. End-of-line sequences are canonicalized to
UNIX-style \n in all modes.
--ignore-case
By default, FileCheck uses case-sensitive matching. This option
causes FileCheck to use case-insensitive matching.
--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.
--dump-input <value>
Dump input to stderr, adding annotations representing currently
enabled diagnostics. When there are multiple occurrences of
this option, the <value> that appears earliest in the list below
has precedence. The default is fail.
• help - Explain input dump and quit
• always - Always dump input
• fail - Dump input on failure
• never - Never dump input
--dump-input-context <N>
In the dump requested by --dump-input, print <N> input lines be-
fore and <N> input lines after any lines specified by --dump-in-
put-filter. When there are multiple occurrences of this option,
the largest specified <N> has precedence. The default is 5.
--dump-input-filter <value>
In the dump requested by --dump-input, print only input lines of
kind <value> plus any context specified by --dump-input-context.
When there are multiple occurrences of this option, the <value>
that appears earliest in the list below has precedence. The de-
fault is error when --dump-input=fail, and it’s all when
--dump-input=always.
• all - All input lines
• annotation-full - Input lines with annotations
• annotation - Input lines with starting points of annota-
tions
• error - Input lines with starting points of error
annotations
--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#<FMT>,<NUMVAR>=<NUMERIC EXPRESSION>
Sets a filecheck numeric variable NUMVAR of matching format FMT
to the result of evaluating <NUMERIC EXPRESSION> that can be
used in CHECK: lines. See section FileCheck Numeric Variables
and Expressions for details on supported numeric expressions.
-version
Show the version number of this program.
-v Print good directive pattern matches. However, if -dump-in-
put=fail or -dump-input=always, add those matches as input anno-
tations instead.
-vv Print information helpful in diagnosing internal FileCheck is-
sues, such as discarded overlapping CHECK-DAG: matches, implicit
EOF pattern matches, and CHECK-NOT: patterns that do not have
matches. Implies -v. However, if -dump-input=fail or -dump-in-
put=always, just add that information as input annotations in-
stead.
--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.
--allow-empty
Allow checking empty input. By default, empty input is rejected.
--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 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 ex-
isted 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 “COM:” directive
Sometimes you want to disable a FileCheck directive without removing it
entirely, or you want to write comments that mention a directive by
name. The “COM:” directive makes it easy to do this. For example, you
might have:
; X32: pinsrd_1:
; X32: pinsrd $1, 4(%esp), %xmm0
; COM: FIXME: X64 isn't working correctly yet for this part of codegen, but
; COM: X64 will have something similar to X32:
; COM:
; COM: X64: pinsrd_1:
; COM: X64: pinsrd $1, %edi, %xmm0
Without “COM:”, you would need to use some combination of rewording and
directive syntax mangling to prevent FileCheck from recognizing the
commented occurrences of “X32:” and “X64:” above as directives. More-
over, FileCheck diagnostics have been proposed that might complain
about the above occurrences of “X64” that don’t have the trailing “:”
because they look like directive typos. Dodging all these problems can
be tedious for a test author, and directive syntax mangling can make
the purpose of test code unclear. “COM:” avoids all these problems.
A few important usage notes:
• “COM:” within another directive’s pattern does not comment out the
remainder of the pattern. For example:
; X32: pinsrd $1, 4(%esp), %xmm0 COM: This is part of the X32 pattern!
If you need to temporarily comment out part of a directive’s pattern,
move it to another line. The reason is that FileCheck parses “COM:”
in the same manner as any other directive: only the first directive
on the line is recognized as a directive.
• For the sake of LIT, FileCheck treats “RUN:” just like “COM:”. If
this is not suitable for your test environment, see
--comment-prefixes.
• FileCheck does not recognize “COM”, “RUN”, or any user-defined com-
ment prefix as a comment directive if it’s combined with one of the
usual check directive suffixes, such as “-NEXT:” or “-NOT:”, dis-
cussed below. FileCheck treats such a combination as plain text in-
stead. If it needs to act as a comment directive for your test envi-
ronment, define it as such with --comment-prefixes.
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 ex-
pect:
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 be-
tween it and the previous directive.
“CHECK-SAME:” is also useful to avoid writing matchers for irrelevant
fields. For example, suppose you’re writing a test which parses a tool
that generates output like this:
Name: foo
Field1: ...
Field2: ...
Field3: ...
Value: 1
Name: bar
Field1: ...
Field2: ...
Field3: ...
Value: 2
Name: baz
Field1: ...
Field2: ...
Field3: ...
Value: 1
To write a test that verifies foo has the value 1, you might first
write this:
CHECK: Name: foo
CHECK: Value: 1{{$}}
However, this would be a bad test: if the value for foo changes, the
test would still pass because the “CHECK: Value: 1” line would match
the value from baz. To fix this, you could add CHECK-NEXT matchers for
every FieldN: line, but that would be verbose, and need to be updated
when Field4 is added. A more succinct way to write the test using the
“CHECK-SAME:” matcher would be as follows:
CHECK: Name: foo
CHECK: Value:
CHECK-SAME: {{ 1$}}
This verifies that the next time “Value:” appears in the output, it has
the value 1.
Note: 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 oc-
cur 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-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 se-
quential 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 ex-
clude strings between the surrounding CHECK-DAG: directives. As a re-
sult, the surrounding CHECK-DAG: directives cannot be reordered, i.e.
all occurrences matching CHECK-DAG: before CHECK-NOT: must not fall be-
hind 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 as-
sumption 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 --en-
able-var-scope is in effect, all local variables are cleared at the be-
ginning 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 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.
Directive modifiers
A directive modifier can be append to a directive by following the di-
rective with {<modifier>} where the only supported value for <modifier>
is LITERAL.
The LITERAL directive modifier can be used to perform a literal match.
The modifier results in the directive not recognizing any syntax to
perform regex matching, variable capture or any substitutions. This is
useful when the text to match would require excessive escaping other-
wise. For example, the following will perform literal matches rather
than considering these as regular expressions:
Input: [[[10, 20]], [[30, 40]]]
Output %r10: [[10, 20]]
Output %r10: [[30, 40]]
; CHECK{LITERAL}: [[[10, 20]], [[30, 40]]]
; CHECK-DAG{LITERAL}: [[30, 40]]
; CHECK-DAG{LITERAL}: [[10, 20]]
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 imple-
ments 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. Or if you are using the repeti-
tion count syntax, for example [[:xdigit:]]{8} to match exactly 8 hex
digits, you would need to add parentheses like this
{{([[:xdigit:]]{8})}} to avoid confusion with FileCheck’s closing dou-
ble-brace.
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 al-
low 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; oth-
erwise, 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 nu-
meric expression constraint based on those variables via a numeric sub-
stitution. 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 capture a numeric value is [[#%<fmtspec>,<NUMVAR>:]]
where:
• %<fmtspec>, is an optional format specifier to indicate what number
format to match and the minimum number of digits to expect.
• <NUMVAR>: is an optional definition of variable <NUMVAR> from the
captured value.
The syntax of <fmtspec> is: #.<precision><conversion specifier> where:
• # is an optional flag available for hex values (see <conversion spec-
ifier> below) which requires the value matched to be prefixed by 0x.
• .<precision> is an optional printf-style precision specifier in which
<precision> indicates the minimum number of digits that the value
matched must have, expecting leading zeros if needed.
• <conversion specifier> is an optional scanf-style conversion speci-
fier to indicate what number format to match (e.g. hex number). Cur-
rently accepted format specifiers are %u, %d, %x and %X. If absent,
the format specifier defaults to %u.
For example:
; CHECK: mov r[[#REG:]], 0x[[#%.8X,ADDR:]]
would match mov r5, 0x0000FEFE and set REG to the value 5 and ADDR to
the value 0xFEFE. Note that due to the precision it would fail to match
mov r5, 0xFEFE.
As a result of the numeric variable definition being optional, it is
possible to only check that a numeric value is present in a given for-
mat. This can be useful when the value itself is not useful, for in-
stance:
; CHECK-NOT: mov r0, r[[#]]
to check that a value is synthesized rather than moved around.
The syntax of a numeric substitution is [[#%<fmtspec>, <constraint>
<expr>]] where:
• <fmtspec> is the same format specifier as for defining a variable but
in this context indicating how a numeric expression value should be
matched against. If absent, both components of the format specifier
are inferred from the matching format of the numeric variable(s) used
by the expression constraint if any, and defaults to %u if no numeric
variable is used, denoting that the value should be unsigned with no
leading zeros. In case of conflict between format specifiers of sev-
eral numeric variables, the conversion specifier becomes mandatory
but the precision specifier remains optional.
• <constraint> is the constraint describing how the value to match must
relate to the value of the numeric expression. The only currently ac-
cepted constraint is == for an exact match and is the default if
<constraint> is not provided. No matching constraint must be speci-
fied when the <expr> is empty.
• <expr> is an expression. An expression is in turn 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, an inte-
ger literal, or a function. Spaces are accepted before, after and be-
tween any of these elements. Numeric operands have 64-bit precision.
Overflow and underflow are rejected. There is no support for operator
precedence, but parentheses can be used to change the evaluation or-
der.
The supported operators are:
• + - Returns the sum of its two operands.
• - - Returns the difference of its two operands.
The syntax of a function call is <name>(<arguments>) where:
• name is a predefined string literal. Accepted values are:
• add - Returns the sum of its two operands.
• div - Returns the quotient of its two operands.
• max - Returns the largest of its two operands.
• min - Returns the smallest of its two operands.
• mul - Returns the product of its two operands.
• sub - Returns the difference of its two operands.
• <arguments> is a comma separated list of expressions.
For example:
; CHECK: load r[[#REG:]], [r0]
; CHECK: load r[[#REG+1]], [r1]
; CHECK: Loading from 0x[[#%x,ADDR:]]
; CHECK-SAME: to 0x[[#ADDR + 7]]
The above example would match the text:
load r5, [r0]
load r6, [r1]
Loading from 0xa0463440 to 0xa0463447
but would not match the text:
load r5, [r0]
load r7, [r1]
Loading from 0xa0463440 to 0xa0463443
Due to 7 being unequal to 5 + 1 and a0463443 being unequal to a0463440
+ 7.
A numeric variable can also be defined to the result of a numeric ex-
pression, in which case the numeric expression constraint is checked
and if verified the variable is assigned to the value. The unified syn-
tax for both checking a numeric expression and capturing its value into
a numeric variable is thus [[#%<fmtspec>,<NUMVAR>: <constraint>
<expr>]] with each element as described previously. One can use this
syntax to make a testcase more self-describing by using variables in-
stead of values:
; CHECK: mov r[[#REG_OFFSET:]], 0x[[#%X,FIELD_OFFSET:12]]
; CHECK-NEXT: load r[[#]], [r[[#REG_BASE:]], r[[#REG_OFFSET]]]
which would match:
mov r4, 0xC
load r6, [r5, r4]
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 earlier in the same CHECK directive.
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 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 expressions understand the @LINE pseudo
numeric variable which evaluates to the line number of the CHECK pat-
tern where it is found.
This way match patterns can be put near the relevant test lines and in-
clude 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
2003-2023, LLVM Project
15 2023-10-16 FILECHECK(1)
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