This fixes a build error introduced by https://reviews.llvm.org/D153587
when using an old version of GCC. See
https://reviews.llvm.org/D153587#4644735 for details.

This fixes a build error introduced by https://reviews.llvm.org/D153587

Extend `GlobPattern` to support brace expansions, e.g., `foo.{c,cpp}` as discussed in https://reviews.llvm.org/D152762#4425203.

The high level change was to turn `Tokens` into a list that gets larger when we see a new brace expansion term. Then in `GlobPattern::match()` we must check against each token group.

This is a breaking change since `{` will no longer match a literal without escaping. However, `\{` will match the literal `{` before and after this change. Also, from a brief survey of LLVM, it seems that `GlobPattern` is mostly used for symbol and path matching, which likely won't need `{` in their patterns.

See https://github.com/devongovett/glob-match#syntax for a nice glob reference.

Reviewed By: MaskRay

Differential Revision: https://reviews.llvm.org/D153587

Update this diagnostic to mention the reason (unmatched '['), matching
the other diagnostic about stray '\'. The original pattern is omitted,
as some users may mention the original pattern in another position, not
repeating it.

The current implementation has two primary issues:

* Matching `a*a*a*b` against `aaaaaa` has exponential complexity.
* BitVector harms data cache and is inefficient for literal matching.

and a minor issue that `\` at the end may cause an out of bounds access
in `StringRef::operator[]`.

Switch to an O(|S|*|P|) greedy algorithm instead: factor the pattern
into segments split by '*'. The segment is matched sequentianlly by
finding the first occurrence past the end of the previous match. This
algorithm is used by lots of fnmatch implementations, including musl and
NetBSD's.

In addition, `optional<StringRef> Exact, Suffix, Prefix` wastes space.
Instead, match the non-metacharacter prefix against the haystack, then
match the pattern with the rest.

In practice `*suffix` style patterns are less common and our new
algorithm is fast enough, so don't bother storing the non-metacharacter
suffix.

Note: brace expansions (D153587) can leverage the `matchOne` function.

Differential Revision: https://reviews.llvm.org/D156046

With C++17 there is no Clang pedantic warning or MSVC C5051.

Causes lld build errors

Use forward declarations (BitVector already had one) and an headers to source file that were implicitly using them.

Reland r375051 (reverted in r375052) after fixing lld tests on Windows in r375126 and r375131.

Original description: Update GlobPattern in libSupport to handle a few more cases. It does not fully match the `fnmatch` used by GNU objcopy since named character classes (e.g. `[[:digit:]]`) are not supported, but this should support most existing use cases (mostly just `*` is what's used anyway).

This will be used to implement the `--wildcard` flag in llvm-objcopy to be more compatible with GNU objcopy.

This is split off of D66613 to land the libSupport changes separately. The llvm-objcopy part will land soon.

Reviewers: jhenderson, MaskRay, evgeny777, espindola, alexshap

Reviewed By: MaskRay

Subscribers: nickdesaulniers, emaste, arichardson, hiraditya, jakehehrlich, abrachet, seiya, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D66613

llvm-svn: 375149