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.TH "FILECHECK" "1" "2016-07-10" "3.8" "LLVM"

.SH NAME

FileCheck \- Flexible pattern matching file verifier

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.SH SYNOPSIS

.sp

\fBFileCheck\fP \fImatch\-filename\fP [\fI\-\-check\-prefix=XXX\fP] [\fI\-\-strict\-whitespace\fP]

.SH DESCRIPTION

.sp

\fBFileCheck\fP 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. \fBllc\fP) contains the expected information

(for example, a movsd from esp or whatever is interesting).  This is similar to

using \fBgrep\fP, but it is optimized for matching multiple different

inputs in one file in a specific order.

.sp

The \fBmatch\-filename\fP file specifies the file that contains the patterns to

match.  The file to verify is read from standard input unless the

\fI\%\-\-input\-file\fP option is used.

.SH OPTIONS

.INDENT 0.0

.TP

.B \-help

Print a summary of command line options.

.UNINDENT

.INDENT 0.0

.TP

.B \-\-check\-prefix prefix

FileCheck searches the contents of \fBmatch\-filename\fP for patterns to

match.  By default, these patterns are prefixed with "\fBCHECK:\fP".

If you\(aqd like to use a different prefix (e.g. because the same input

file is checking multiple different tool or options), the

\fI\%\-\-check\-prefix\fP 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.

.UNINDENT

.INDENT 0.0

.TP

.B \-\-input\-file filename

File to check (defaults to stdin).

.UNINDENT

.INDENT 0.0

.TP

.B \-\-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 \fI\%\-\-strict\-whitespace\fP argument disables this behavior. End\-of\-line

sequences are canonicalized to UNIX\-style \fB\en\fP in all modes.

.UNINDENT

.INDENT 0.0

.TP

.B \-\-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

\fBCHECK\-NOT\fPs.

.sp

For example, "\fB\-\-implicit\-check\-not warning:\fP" can be useful when testing

diagnostic messages from tools that don\(aqt have an option similar to \fBclang

\-verify\fP\&. With this option FileCheck will verify that input does not contain

warnings not covered by any \fBCHECK:\fP patterns.

.UNINDENT

.INDENT 0.0

.TP

.B \-version

Show the version number of this program.

.UNINDENT

.SH EXIT STATUS

.sp

If \fBFileCheck\fP 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.

.SH TUTORIAL

.sp

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:

.INDENT 0.0

.INDENT 3.5

.sp

.nf

.ft C

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

.ft P

.fi

.UNINDENT

.UNINDENT

.sp

This syntax says to pipe the current file ("\fB%s\fP") into \fBllvm\-as\fP, pipe

that into \fBllc\fP, then pipe the output of \fBllc\fP into \fBFileCheck\fP\&.  This

means that FileCheck will be verifying its standard input (the llc output)

against the filename argument specified (the original \fB\&.ll\fP file specified by

"\fB%s\fP").  To see how this works, let\(aqs look at the rest of the \fB\&.ll\fP file

(after the RUN line):

.INDENT 0.0

.INDENT 3.5

.sp

.nf

.ft C

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

}

.ft P

.fi

.UNINDENT

.UNINDENT

.sp

Here you can see some "\fBCHECK:\fP" lines specified in comments.  Now you can

see how the file is piped into \fBllvm\-as\fP, then \fBllc\fP, and the machine code

output is what we are verifying.  FileCheck checks the machine code output to

verify that it matches what the "\fBCHECK:\fP" lines specify.

.sp

The syntax of the "\fBCHECK:\fP" 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 "\fBCHECK:\fP" line is required to match some thing in the test file exactly.

.sp

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 "\fBsub1:\fP" and "\fBinc4:\fP" labels, it will not match

unless there is a "\fBsubl\fP" in between those labels.  If it existed somewhere

else in the file, that would not count: "\fBgrep subl\fP" matches if "\fBsubl\fP"

exists anywhere in the file.

.SS The FileCheck \-check\-prefix option

.sp

The FileCheck \fB\-check\-prefix\fP option allows multiple test

configurations to be driven from one \fI\&.ll\fP file.  This is useful in many

circumstances, for example, testing different architectural variants with

\fBllc\fP\&.  Here\(aqs a simple example:

.INDENT 0.0

.INDENT 3.5

.sp

.nf

.ft C

; RUN: llvm\-as < %s | llc \-mtriple=i686\-apple\-darwin9 \-mattr=sse41 \e

; RUN:              | FileCheck %s \-check\-prefix=X32

; RUN: llvm\-as < %s | llc \-mtriple=x86_64\-apple\-darwin9 \-mattr=sse41 \e

; 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

}

.ft P

.fi

.UNINDENT

.UNINDENT

.sp

In this case, we\(aqre testing that we get the expected code generation with

both 32\-bit and 64\-bit code generation.

.SS The "CHECK\-NEXT:" directive

.sp

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 "\fBCHECK:\fP" and "\fBCHECK\-NEXT:\fP" directives to specify

this.  If you specified a custom check prefix, just use "\fB<PREFIX>\-NEXT:\fP".

For example, something like this works as you\(aqd expect:

.INDENT 0.0

.INDENT 3.5

.sp

.nf

.ft C

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

}

.ft P

.fi

.UNINDENT

.UNINDENT

.sp

"\fBCHECK\-NEXT:\fP" directives reject the input unless there is exactly one

newline between it and the previous directive.  A "\fBCHECK\-NEXT:\fP" cannot be

the first directive in a file.

.SS The "CHECK\-SAME:" directive

.sp

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 "\fBCHECK:\fP"

and "\fBCHECK\-SAME:\fP" directives to specify this.  If you specified a custom

check prefix, just use "\fB<PREFIX>\-SAME:\fP".

.sp

"\fBCHECK\-SAME:\fP" is particularly powerful in conjunction with "\fBCHECK\-NOT:\fP"

(described below).

.sp

For example, the following works like you\(aqd expect:

.INDENT 0.0

.INDENT 3.5

.sp

.nf

.ft C

!0 = !DILocation(line: 5, scope: !1, inlinedAt: !2)

; CHECK:       !DILocation(line: 5,

; CHECK\-NOT:               column:

; CHECK\-SAME:              scope: ![[SCOPE:[0\-9]+]]

.ft P

.fi

.UNINDENT

.UNINDENT

.sp

"\fBCHECK\-SAME:\fP" directives reject the input if there are any newlines between

it and the previous directive.  A "\fBCHECK\-SAME:\fP" cannot be the first

directive in a file.

.SS The "CHECK\-NOT:" directive

.sp

The "\fBCHECK\-NOT:\fP" directive is used to verify that a string doesn\(aqt 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:

.INDENT 0.0

.INDENT 3.5

.sp

.nf

.ft C

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

}

.ft P

.fi

.UNINDENT

.UNINDENT

.SS The "CHECK\-DAG:" directive

.sp

If it\(aqs necessary to match strings that don\(aqt occur in a strictly sequential

order, "\fBCHECK\-DAG:\fP" 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 \fBCHECK\-DAG:\fP, we can keep the checks

in the natural order:

.INDENT 0.0

.INDENT 3.5

.sp

.nf

.ft C

// 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 =

.ft P

.fi

.UNINDENT

.UNINDENT

.sp

\fBCHECK\-NOT:\fP directives could be mixed with \fBCHECK\-DAG:\fP directives to

exclude strings between the surrounding \fBCHECK\-DAG:\fP directives. As a result,

the surrounding \fBCHECK\-DAG:\fP directives cannot be reordered, i.e. all

occurrences matching \fBCHECK\-DAG:\fP before \fBCHECK\-NOT:\fP must not fall behind

occurrences matching \fBCHECK\-DAG:\fP after \fBCHECK\-NOT:\fP\&. For example,

.INDENT 0.0

.INDENT 3.5

.sp

.nf

.ft C

; CHECK\-DAG: BEFORE

; CHECK\-NOT: NOT

; CHECK\-DAG: AFTER

.ft P

.fi

.UNINDENT

.UNINDENT

.sp

This case will reject input strings where \fBBEFORE\fP occurs after \fBAFTER\fP\&.

.sp

With captured variables, \fBCHECK\-DAG:\fP is able to match valid topological

orderings of a DAG with edges from the definition of a variable to its use.

It\(aqs useful, e.g., when your test cases need to match different output

sequences from the instruction scheduler. For example,

.INDENT 0.0

.INDENT 3.5

.sp

.nf

.ft C

; CHECK\-DAG: add [[REG1:r[0\-9]+]], r1, r2

; CHECK\-DAG: add [[REG2:r[0\-9]+]], r3, r4

; CHECK:     mul r5, [[REG1]], [[REG2]]

.ft P

.fi

.UNINDENT

.UNINDENT

.sp

In this case, any order of that two \fBadd\fP instructions will be allowed.

.sp

If you are defining \fIand\fP using variables in the same \fBCHECK\-DAG:\fP block,

be aware that the definition rule can match \fIafter\fP its use.

.sp

So, for instance, the code below will pass:

.INDENT 0.0

.INDENT 3.5

.sp

.nf

.ft C

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

; CHECK\-DAG: vmov.32 [[REG2]][1]

vmov.32 d0[1]

vmov.32 d0[0]

.ft P

.fi

.UNINDENT

.UNINDENT

.sp

While this other code, will not:

.INDENT 0.0

.INDENT 3.5

.sp

.nf

.ft C

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

; CHECK\-DAG: vmov.32 [[REG2]][1]

vmov.32 d1[1]

vmov.32 d0[0]

.ft P

.fi

.UNINDENT

.UNINDENT

.sp

While this can be very useful, it\(aqs 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\(aqt match (because

of a bug in the compiler), it may match further away from the use, and mask

real bugs away.

.sp

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

.SS The "CHECK\-LABEL:" directive

.sp

Sometimes in a file containing multiple tests divided into logical blocks, one

or more \fBCHECK:\fP 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.

.sp

In order to produce better error messages in these cases, the "\fBCHECK\-LABEL:\fP"

directive can be used. It is treated identically to a normal \fBCHECK\fP

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

\fBmatch\-filename\fP; this is intended to be used for lines containing labels or

other unique identifiers. Conceptually, the presence of \fBCHECK\-LABEL\fP divides

the input stream into separate blocks, each of which is processed independently,

preventing a \fBCHECK:\fP directive in one block matching a line in another block.

For example,

.INDENT 0.0

.INDENT 3.5

.sp

.nf

.ft C

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:

.ft P

.fi

.UNINDENT

.UNINDENT

.sp

The use of \fBCHECK\-LABEL:\fP directives in this case ensures that the three

\fBCHECK:\fP directives only accept lines corresponding to the body of the

\fB@C_ctor_base\fP function, even if the patterns match lines found later in

the file. Furthermore, if one of these three \fBCHECK:\fP directives fail,

FileCheck will recover by continuing to the next block, allowing multiple test

failures to be detected in a single invocation.

.sp

There is no requirement that \fBCHECK\-LABEL:\fP 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.

.sp

\fBCHECK\-LABEL:\fP directives cannot contain variable definitions or uses.

.SS FileCheck Pattern Matching Syntax

.sp

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: \fB{{yourregex}}\fP\&.  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:

.INDENT 0.0

.INDENT 3.5

.sp

.nf

.ft C

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

.ft P

.fi

.UNINDENT

.UNINDENT

.sp

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

register will be allowed.

.sp

Because regular expressions are enclosed with double braces, they are

visually distinct, and you don\(aqt 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

\fB{{[{][{]}}\fP as your pattern.

.SS FileCheck Variables

.sp

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,

\fBFileCheck\fP allows named variables to be defined and substituted into

patterns.  Here is a simple example:

.INDENT 0.0

.INDENT 3.5

.sp

.nf

.ft C

; CHECK: test5:

; CHECK:    notw     [[REGISTER:%[a\-z]+]]

; CHECK:    andw     {{.*}}[[REGISTER]]

.ft P

.fi

.UNINDENT

.UNINDENT

.sp

The first check line matches a regex \fB%[a\-z]+\fP and captures it into the

variable \fBREGISTER\fP\&.  The second line verifies that whatever is in

\fBREGISTER\fP occurs later in the file after an "\fBandw\fP".  \fBFileCheck\fP

variable references are always contained in \fB[[ ]]\fP pairs, and their names can

be formed with the regex \fB[a\-zA\-Z][a\-zA\-Z0\-9]*\fP\&.  If a colon follows the name,

then it is a definition of the variable; otherwise, it is a use.

.sp

\fBFileCheck\fP 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:

.INDENT 0.0

.INDENT 3.5

.sp

.nf

.ft C

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

.ft P

.fi

.UNINDENT

.UNINDENT

.sp

Can be useful if you want the operands of \fBop\fP to be the same register,

and don\(aqt care exactly which register it is.

.SS FileCheck Expressions

.sp

Sometimes there\(aqs 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 "\fBCHECK:\fP" lines contain absolute

line numbers in the same file, which have to be updated whenever line numbers

change due to text addition or deletion.

.sp

To support this case, FileCheck allows using \fB[[@LINE]]\fP,