[FileCheck] Annotate input dump (3/7)

This patch implements input annotations for diagnostics that report
wrong-line matches for the directives CHECK-NEXT, CHECK-SAME, and
CHECK-EMPTY.  Instead of the usual `^~~`, which is used by later
patches for good matches, these annotations use `!~~` to mark the bad
match ranges so that this category of errors is visually distinct.
Because such matches are errors, these annotates are red when colors
are enabled.

For example:

```
$ FileCheck -dump-input=help
The following description was requested by -dump-input=help to
explain the input annotations printed by -dump-input=always and
-dump-input=fail:

  - L:     labels line number L of the input file
  - T:L    labels the only match result for a pattern of type T from line L of
           the check file
  - T:L'N  labels the Nth match result for a pattern of type T from line L of
           the check file
  - !~~    marks bad match, such as:
           - CHECK-NEXT on same line as previous match (error)
  - X~~    marks search range when no match is found, such as:
           - CHECK-NEXT not found (error)
  - ?      marks fuzzy match when no match is found
  - colors error, fuzzy match

If you are not seeing color above or in input dumps, try: -color

$ FileCheck -v -dump-input=always check2 < input2 |& sed -n '/^<<<</,$p'
<<<<<<
        1: foo bar
next:2         !~~ error: match on wrong line
>>>>>>

$ cat check2
CHECK: foo
CHECK-NEXT: bar

$ cat input2
foo bar
```

Reviewed By: george.karpenkov, probinson

Differential Revision: https://reviews.llvm.org/D53894

llvm-svn: 349420

1 files changed, 13 insertions, 3 deletions

diff --git a/llvm/lib/Support/FileCheck.cpp b/llvm/lib/Support/FileCheck.cpp
index 49e2500a63a..817e8d95bf0 100644
--- a/llvm/lib/Support/FileCheck.cpp
+++ b/llvm/lib/Support/FileCheck.cpp
@@ -1047,17 +1047,27 @@ size_t FileCheckString::Check(const SourceMgr &SM, StringRef Buffer,
   // Similar to the above, in "label-scan mode" we can't yet handle CHECK-NEXT
   // or CHECK-NOT
   if (!IsLabelScanMode) {
-    StringRef SkippedRegion = Buffer.substr(LastPos, FirstMatchPos - LastPos);
+    size_t MatchPos = FirstMatchPos - LastPos;
+    StringRef MatchBuffer = Buffer.substr(LastPos);
+    StringRef SkippedRegion = Buffer.substr(LastPos, MatchPos);
 
     // If this check is a "CHECK-NEXT", verify that the previous match was on
     // the previous line (i.e. that there is one newline between them).
-    if (CheckNext(SM, SkippedRegion))
+    if (CheckNext(SM, SkippedRegion)) {
+      ProcessMatchResult(FileCheckDiag::MatchFinalButWrongLine, SM, Loc,
+                         Pat.getCheckTy(), MatchBuffer, MatchPos, MatchLen,
+                         Diags);
       return StringRef::npos;
+    }
 
     // If this check is a "CHECK-SAME", verify that the previous match was on
     // the same line (i.e. that there is no newline between them).
-    if (CheckSame(SM, SkippedRegion))
+    if (CheckSame(SM, SkippedRegion)) {
+      ProcessMatchResult(FileCheckDiag::MatchFinalButWrongLine, SM, Loc,
+                         Pat.getCheckTy(), MatchBuffer, MatchPos, MatchLen,
+                         Diags);
       return StringRef::npos;
+    }
 
     // If this match had "not strings", verify that they don't exist in the
     // skipped region.