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.
--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 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-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-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
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}}. 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
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 (http://llvm.org/).
COPYRIGHT
2003-2017, LLVM Project
4 2017-10-18 FILECHECK(1)
