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       FileCheck - Flexible pattern matching file verifier

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

       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.

       -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	one or
	      more prefixes to match. Multiple prefixes	are useful  for	 tests
	      which might change for different run options, but	most lines re-
	      main 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).

	      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.

	      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:

	      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

	      Sets a filecheck variable	VAR with value VALUE that can be  used
	      in CHECK:	lines.

	      Show the version number of this program.

       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.

       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) {
	  ; 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) {
	  ; 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 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-

	  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.  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 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-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,


       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

   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) {
	  ; 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) {
	  ; 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

       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}}. 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.

   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  al-
       low  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.

       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 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  op-
       tional integer offset).

       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

   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".

       Maintained by The LLVM Team (

       2003-2021, LLVM Project

6				  2021-02-28			  FILECHECK(1)


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