FileCheck: Add CHECK-SAME

Add `CHECK-SAME`, which requires that the pattern matches on the *same*
line as the previous `CHECK`/`CHECK-NEXT` -- in other words, no newline
is allowed in the skipped region.  This is similar to `CHECK-NEXT`,
which requires exactly 1 newline in the skipped region.

My motivation is to simplify checking the long lines of LLVM assembly
for the new debug info hierarchy.  This allows CHECK sequences like the
following:

    CHECK:      ![[REF]] = !SomeMDNode(
    CHECK-SAME: file: ![[FILE:[0-9]+]]
    CHECK-SAME: otherField: 93{{[,)]}}

which is equivalent to:

    CHECK: ![[REF]] = !SomeMDNode({{.*}}file: ![[FILE:[0-9]+]]{{.*}}otherField: 93{{[,)]}}

While this example just has two fields, many nodes in debug info have
more than that.  `CHECK-SAME` will keep the logic easy to follow.

Morever, it enables interleaving `CHECK-NOT`s without allowing newlines.
Consider the following:

    CHECK:      ![[REF]] = !SomeMDNode(
    CHECK-SAME: file: ![[FILE:[0-9]+]]
    CHECK-NOT:  unexpectedField:
    CHECK-SAME: otherField: 93{{[,)]}}
    CHECK-NOT:  otherUnexpectedField:
    CHECK-SAME: )

which doesn't seem to have an equivalent `CHECK` line.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@230612 91177308-0d34-0410-b5e6-96231b3b80d8

test/FileCheck/same.txt

@@ -0,0 +1,23 @@
+foo bat bar
+baz
+
+RUN: FileCheck --input-file=%s --check-prefix=PASS1 %s
+PASS1: foo
+PASS1-SAME: bat
+PASS1-SAME: bar
+PASS1-NEXT: baz
+
+RUN: FileCheck --input-file=%s --check-prefix=PASS2 %s
+PASS2: foo
+PASS2-NOT: baz
+PASS2-SAME: bar
+PASS2-NEXT: baz
+
+RUN: not FileCheck --input-file=%s --check-prefix=FAIL1 %s
+FAIL1: foo
+FAIL1-SAME: baz
+
+RUN: not FileCheck --input-file=%s --check-prefix=FAIL2 %s
+FAIL2: foo
+FAIL2-NOT: bat
+FAIL2-SAME: bar

utils/FileCheck/FileCheck.cpp

@@ -73,6 +73,7 @@ namespace Check {
     CheckNone = 0,
     CheckPlain,
     CheckNext,
+    CheckSame,
     CheckNot,
     CheckDAG,
     CheckLabel,
@@ -620,6 +621,9 @@ struct CheckString {
   /// CheckNext - Verify there is a single line in the given buffer.
   bool CheckNext(const SourceMgr &SM, StringRef Buffer) const;
 
+  /// CheckSame - Verify there is no newline in the given buffer.
+  bool CheckSame(const SourceMgr &SM, StringRef Buffer) const;
+
   /// CheckNot - Verify there's no "not strings" in the given buffer.
   bool CheckNot(const SourceMgr &SM, StringRef Buffer,
                 const std::vector<const Pattern *> &NotStrings,
@@ -683,6 +687,9 @@ static size_t CheckTypeSize(Check::CheckType Ty) {
   case Check::CheckNext:
     return sizeof("-NEXT:") - 1;
 
+  case Check::CheckSame:
+    return sizeof("-SAME:") - 1;
+
   case Check::CheckNot:
     return sizeof("-NOT:") - 1;
 
@@ -713,6 +720,9 @@ static Check::CheckType FindCheckType(StringRef Buffer, StringRef Prefix) {
   if (Rest.startswith("NEXT:"))
     return Check::CheckNext;
 
+  if (Rest.startswith("SAME:"))
+    return Check::CheckSame;
+
   if (Rest.startswith("NOT:"))
     return Check::CheckNot;
 
@@ -919,10 +929,12 @@ static bool ReadCheckFile(SourceMgr &SM,
     Buffer = Buffer.substr(EOL);
 
     // Verify that CHECK-NEXT lines have at least one CHECK line before them.
-    if ((CheckTy == Check::CheckNext) && CheckStrings.empty()) {
+    if ((CheckTy == Check::CheckNext || CheckTy == Check::CheckSame) &&
+        CheckStrings.empty()) {
+      StringRef Type = CheckTy == Check::CheckNext ? "NEXT" : "SAME";
       SM.PrintMessage(SMLoc::getFromPointer(UsedPrefixStart),
                       SourceMgr::DK_Error,
-                      "found '" + UsedPrefix + "-NEXT:' without previous '"
+                      "found '" + UsedPrefix + "-" + Type + "' without previous '"
                       + UsedPrefix + ": line");
       return true;
     }
@@ -1053,6 +1065,11 @@ size_t CheckString::Check(const SourceMgr &SM, StringRef Buffer,
     if (CheckNext(SM, SkippedRegion))
       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))
+      return StringRef::npos;
+
     // If this match had "not strings", verify that they don't exist in the
     // skipped region.
     if (CheckNot(SM, SkippedRegion, NotStrings, VariableTable))
@@ -1101,6 +1118,34 @@ bool CheckString::CheckNext(const SourceMgr &SM, StringRef Buffer) const {
   return false;
 }
 
+bool CheckString::CheckSame(const SourceMgr &SM, StringRef Buffer) const {
+  if (CheckTy != Check::CheckSame)
+    return false;
+
+  // Count the number of newlines between the previous match and this one.
+  assert(Buffer.data() !=
+             SM.getMemoryBuffer(SM.FindBufferContainingLoc(
+                                    SMLoc::getFromPointer(Buffer.data())))
+                 ->getBufferStart() &&
+         "CHECK-SAME can't be the first check in a file");
+
+  const char *FirstNewLine = nullptr;
+  unsigned NumNewLines = CountNumNewlinesBetween(Buffer, FirstNewLine);
+
+  if (NumNewLines != 0) {
+    SM.PrintMessage(Loc, SourceMgr::DK_Error,
+                    Prefix +
+                        "-SAME: is not on the same line as the previous match");
+    SM.PrintMessage(SMLoc::getFromPointer(Buffer.end()), SourceMgr::DK_Note,
+                    "'next' match was here");
+    SM.PrintMessage(SMLoc::getFromPointer(Buffer.data()), SourceMgr::DK_Note,
+                    "previous match ended here");
+    return true;
+  }
+
+  return false;
+}
+
 bool CheckString::CheckNot(const SourceMgr &SM, StringRef Buffer,
                            const std::vector<const Pattern *> &NotStrings,
                            StringMap<StringRef> &VariableTable) const {