Provided by: llvm-3.3_3.3-16ubuntu1_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
always read from standard input.
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 a specific prefix to match.
--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 disables
this behavior. End-of-line sequences are canonicalized to UNIX-style 'n' in all modes.
-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 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-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
}
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 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 REGISTER occurs later in the file after an "andw". FileCheck variable
references 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 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 allows using [[@LINE]], [[@LINE+<offset>]], [[@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
2003-2013, LLVM Project