docs/CommandGuide/FileCheck.rst - platform/external/llvm - Git at Google

 FileCheck - Flexible pattern matching file verifier
 ===================================================

 SYNOPSIS
 --------

 :program:`FileCheck` *match-filename* [*--check-prefix=XXX*] [*--strict-whitespace*]

 DESCRIPTION
 -----------

 :program:`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. :program:`llc`) contains the expected information
 (for example, a movsd from esp or whatever is interesting).  This is similar to
 using :program:`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
 -------

 .. option:: -help

  Print a summary of command line options.

 .. option:: --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 :option:`--check-prefix` argument allows you
  to specify a specific prefix to match.

 .. option:: --input-file filename

   File to check (defaults to stdin).

 .. option:: --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 :option:`--strict-whitespace` argument disables this behavior. End-of-line
  sequences are canonicalized to UNIX-style '\n' in all modes.

 .. option:: -version

  Show the version number of this program.

 EXIT STATUS
 -----------

 If :program:`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:

 .. code-block:: llvm

    ; 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):

 .. code-block:: llvm

    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 :option:`-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
 :program:`llc`.  Here's a simple example:

 .. code-block:: llvm

    ; 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:

 .. code-block:: llvm

    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:

 .. code-block:: llvm

    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:

 .. code-block:: llvm

    ; 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,
 :program:`FileCheck` allows named variables to be defined and substituted into
 patterns.  Here is a simple example:

 .. code-block:: llvm

    ; 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``".  :program:`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.

 :program:`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:

 .. code-block:: llvm

     ; 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:

 .. code-block:: c++

    // CHECK: test.cpp:[[@LINE+4]]:6: error: expected ';' after top level declarator
    // CHECK-NEXT: {{^int a}}
    // CHECK-NEXT: {{^     \^}}
    // CHECK-NEXT: {{^     ;}}
    int a
	FileCheck - Flexible pattern matching file verifier
	===================================================

	SYNOPSIS
	--------

	:program:`FileCheck` match-filename [--check-prefix=XXX] [--strict-whitespace]

	DESCRIPTION
	-----------

	:program:`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. :program:`llc`) contains the expected information
	(for example, a movsd from esp or whatever is interesting). This is similar to
	using :program:`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
	-------

	.. option:: -help

	Print a summary of command line options.

	.. option:: --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 :option:`--check-prefix` argument allows you
	to specify a specific prefix to match.

	.. option:: --input-file filename

	File to check (defaults to stdin).

	.. option:: --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 :option:`--strict-whitespace` argument disables this behavior. End-of-line
	sequences are canonicalized to UNIX-style '\n' in all modes.

	.. option:: -version

	Show the version number of this program.

	EXIT STATUS
	-----------

	If :program:`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:

	.. code-block:: llvm

	; 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):

	.. code-block:: llvm

	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 :option:`-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
	:program:`llc`. Here's a simple example:

	.. code-block:: llvm

	; 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:

	.. code-block:: llvm

	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:

	.. code-block:: llvm

	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:

	.. code-block:: llvm

	; 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,
	:program:`FileCheck` allows named variables to be defined and substituted into
	patterns. Here is a simple example:

	.. code-block:: llvm

	; 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``". :program:`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.

	:program:`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:

	.. code-block:: llvm

	; 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:

	.. code-block:: c++

	// CHECK: test.cpp:[[@LINE+4]]:6: error: expected ';' after top level declarator
	// CHECK-NEXT: {{^int a}}
	// CHECK-NEXT: {{^ \^}}
	// CHECK-NEXT: {{^ ;}}
	int a