[FileCheck] Add --check-prefixes as a shorthand for multiple --check-prefix options.

[dsanders]

Summary

This new alias takes a comma separated list of prefixes which allows
'--check-prefix=A --check-prefix=B --check-prefix=C' to be written as
'--check-prefixes=A,B,C'.

Depends on D21292 since it reduces the line length of elf_header.s.

[probinson]

Wow. I am blown away by the sophisticated implementation. :-)

So, the MC/Mips test ought to be committed separately (as part of D21292 clearly).
Also I think you went a bit overboard with the FileCheck tests, no need to replicate *all* the multi-prefix runs. I'd think a couple representative tests would be enough, maybe just check-multiple-prefixes-mixed.txt and multiple-missing-prefixes.txt.

With that, LGTM.

[dsanders]

Wow. I am blown away by the sophisticated implementation. :-)

I didn't believe it could be that simple.

So, the MC/Mips test ought to be committed separately (as part of D21292 clearly).

Yep, it's in here because of the order of the patches in my current series but it looks like this will be committed first so I'll fold that part into D21292.

Also I think you went a bit overboard with the FileCheck tests, no need to replicate *all* the multi-prefix runs. I'd think a couple representative tests would be enough, maybe just check-multiple-prefixes-mixed.txt and multiple-missing-prefixes.txt.

Makes sense. In addition to the two you mention, I'll also keep the two *-no-match*.txt tests. Most of the tests can falsely pass if only one prefix takes effect so the *-no-match*.txt tests are needed to make sure all the prefixes are being processed.

With that, LGTM.

Thanks

[dsanders]

Remove elf_header.s it will be folded into D21292.
Remove unnecessary tests.

[probinson]

Doh! Forgot to say... please document this new option (docs/CommandGuide/FileCheck.rst).

[dsanders]

Added documentation in r272683.

llvm/trunk/test/FileCheck/check-multiple-prefixes-mixed.txt

 // RUN: FileCheck -check-prefix=B -check-prefix=BOTH -input-file %s %s
 // RUN: FileCheck -check-prefix=A -check-prefix=BOTH -input-file %s %s
+// RUN: FileCheck -check-prefixes=B,BOTH -input-file %s %s
+// RUN: FileCheck -check-prefixes=A,BOTH -input-file %s %s
 
 ; A: {{a}}aaaaa
 ; B: {{b}}bbbb
 ; BOTH: {{q}}qqqqq
 aaaaaa
 bbbbb
 qqqqqq
 ccccc

llvm/trunk/test/FileCheck/check-multiple-prefixes-nomatch-2.txt

 ; RUN: not FileCheck -input-file %s %s -check-prefix=FOO -check-prefix=BAR 2>&1 | FileCheck %s
+; RUN: not FileCheck -input-file %s %s -check-prefixes=FOO,BAR 2>&1 | FileCheck %s
+; RUN: not FileCheck -input-file %s %s -check-prefixes=BAR,FOO 2>&1 | FileCheck %s
 
 fog
 bar
 ; _FOO not a valid check-line
 ; FOO: fo{{o}}
 ; BAR: ba{{r}}
 
 ; CHECK: {{error: expected string not found in input}}
 ; CHECK-NEXT: {{F}}OO: fo{{[{][{]o[}][}]}}

llvm/trunk/test/FileCheck/check-multiple-prefixes-nomatch.txt

 ; RUN: not FileCheck -input-file %s %s -check-prefix=FOO -check-prefix=BAR 2>&1 | FileCheck %s
+; RUN: not FileCheck -input-file %s %s -check-prefixes=FOO,BAR 2>&1 | FileCheck %s
+; RUN: not FileCheck -input-file %s %s -check-prefixes=BAR,FOO 2>&1 | FileCheck %s
 
 BAR
 bar
 foo
 ; BAR: ba{{z}}
 ; FOO: fo{{o}}
 
 ; CHECK: {{error: expected string not found in input}}
 ; CHECK-NEXT: {{B}}AR: ba{{[{][{]z[}][}]}}

llvm/trunk/test/FileCheck/multiple-missing-prefixes.txt

 // RUN: FileCheck -check-prefix=ANOTHER-PREFIX -input-file %s %s
 // RUN: not FileCheck -check-prefix=PREFIX1 -check-prefix=PREFIX2 -input-file %s %s 2>&1 | FileCheck -strict-whitespace -check-prefix=CHECK-NONEXISTENT-PREFIX -check-prefix=ALSO-NONEXISTENT %s
+// RUN: not FileCheck -check-prefixes=PREFIX1,PREFIX2 -input-file %s %s 2>&1 | FileCheck -strict-whitespace -check-prefixes=CHECK-NONEXISTENT-PREFIX,ALSO-NONEXISTENT %s
 
 foobar
 ; ANOTHER-PREFIX: foobar
 
 ; We use regex to match the colon so that FileCheck won't think it is a check
 ; prefix.
 ; CHECK-NONEXISTENT-PREFIX: error: no check strings found with prefixes 'PREFIX1{{:}}', 'PREFIX2{{:}}'

llvm/trunk/utils/FileCheck/FileCheck.cpp

 
 static cl::opt<std::string>
 InputFilename("input-file", cl::desc("File to check (defaults to stdin)"),
               cl::init("-"), cl::value_desc("filename"));
 
 static cl::list<std::string>
 CheckPrefixes("check-prefix",
               cl::desc("Prefix to use from check file (defaults to 'CHECK')"));
+static cl::alias CheckPrefixesAlias(
+    "check-prefixes", cl::aliasopt(CheckPrefixes), cl::CommaSeparated,
+    cl::NotHidden,
+    cl::desc(
+        "Alias for -check-prefix permitting multiple comma separated values"));
 
 static cl::opt<bool>
 NoCanonicalizeWhiteSpace("strict-whitespace",
               cl::desc("Do not treat all horizontal whitespace as equivalent"));
 
 static cl::list<std::string> ImplicitCheckNot(
     "implicit-check-not",
     cl::desc("Add an implicit negative check with this pattern to every\n"