FileCheck [1/12]: Move variable table in new object

Summary:
This patch is part of a patch series to add support for FileCheck
numeric expressions. This specific patch adds a new class to hold
pattern matching global state.

The table holding the values of FileCheck variable constitutes some sort
of global state for the matching phase, yet is passed as parameters of
all functions using it. This commit create a new FileCheckPatternContext
class pointed at from FileCheckPattern. While it increases the line
count, it separates local data from global state. Later commits build
on that to add numeric expression global state to that class.

Copyright:
    - Linaro (changes up to diff 183612 of revision D55940)
    - GraphCore (changes in later versions of revision D55940 and
                 in new revision created off D55940)

Reviewers: jhenderson, chandlerc, jdenny, probinson, grimar, arichardson, rnk

Subscribers: hiraditya, llvm-commits, probinson, dblaikie, grimar, arichardson, tra, rnk, kristina, hfinkel, rogfer01, JonChesterfield

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D60381

llvm-svn: 358390

llvm/include/llvm/Support/FileCheck.h

@@ -79,10 +79,37 @@ class FileCheckType {
 
   std::string getDescription(StringRef Prefix) const;
 };
-}
+} // namespace Check
 
 struct FileCheckDiag;
 
+/// Class holding the FileCheckPattern global state, shared by all patterns:
+/// tables holding values of variables and whether they are defined or not at
+/// any given time in the matching process.
+class FileCheckPatternContext {
+  friend class FileCheckPattern;
+
+private:
+  /// When matching a given pattern, this holds the value of all the FileCheck
+  /// variables defined in previous patterns. In a pattern only the last
+  /// definition for a given variable is recorded in this table, back-references
+  /// are used for uses after any the other definition.
+  StringMap<StringRef> GlobalVariableTable;
+
+public:
+  /// Return the value of variable \p VarName or None if no such variable has
+  /// been defined.
+  llvm::Optional<StringRef> getVarValue(StringRef VarName);
+
+  /// Define variables from definitions given on the command line passed as a
+  /// vector of VAR=VAL strings in \p CmdlineDefines.
+  void defineCmdlineVariables(std::vector<std::string> &CmdlineDefines);
+
+  /// Undefine local variables (variables whose name does not start with a '$'
+  /// sign), i.e. remove them from GlobalVariableTable.
+  void clearLocalVars();
+};
+
 class FileCheckPattern {
   SMLoc PatternLoc;
 
@@ -106,27 +133,34 @@ class FileCheckPattern {
   /// 1.
   std::map<StringRef, unsigned> VariableDefs;
 
+  /// Pointer to the class instance shared by all patterns holding a table with
+  /// the values of live variables at the start of any given CHECK line.
+  FileCheckPatternContext *Context;
+
   Check::FileCheckType CheckTy;
 
   /// Contains the number of line this pattern is in.
   unsigned LineNumber;
 
 public:
-  explicit FileCheckPattern(Check::FileCheckType Ty)
-      : CheckTy(Ty) {}
+  explicit FileCheckPattern(Check::FileCheckType Ty,
+                            FileCheckPatternContext *Context)
+      : Context(Context), CheckTy(Ty) {}
 
   /// Returns the location in source code.
   SMLoc getLoc() const { return PatternLoc; }
 
+  /// Returns the pointer to the global state for all patterns in this
+  /// FileCheck instance.
+  FileCheckPatternContext *getContext() const { return Context; }
   bool ParsePattern(StringRef PatternStr, StringRef Prefix, SourceMgr &SM,
                     unsigned LineNumber, const FileCheckRequest &Req);
-  size_t Match(StringRef Buffer, size_t &MatchLen,
-               StringMap<StringRef> &VariableTable) const;
-  void PrintVariableUses(const SourceMgr &SM, StringRef Buffer,
-                         const StringMap<StringRef> &VariableTable,
+  size_t match(StringRef Buffer, size_t &MatchLen) const;
+  /// Print value of successful substitutions or name of undefined pattern
+  /// variables preventing such a successful substitution.
+  void printVariableUses(const SourceMgr &SM, StringRef Buffer,
                          SMRange MatchRange = None) const;
-  void PrintFuzzyMatch(const SourceMgr &SM, StringRef Buffer,
-                       const StringMap<StringRef> &VariableTable,
+  void printFuzzyMatch(const SourceMgr &SM, StringRef Buffer,
                        std::vector<FileCheckDiag> *Diags) const;
 
   bool hasVariable() const {
@@ -140,9 +174,7 @@ class FileCheckPattern {
 private:
   bool AddRegExToRegEx(StringRef RS, unsigned &CurParen, SourceMgr &SM);
   void AddBackrefToRegEx(unsigned BackrefNum);
-  unsigned
-  ComputeMatchDistance(StringRef Buffer,
-                       const StringMap<StringRef> &VariableTable) const;
+  unsigned computeMatchDistance(StringRef Buffer) const;
   bool EvaluateExpression(StringRef Expr, std::string &Value) const;
   size_t FindRegexVarEnd(StringRef Str, SourceMgr &SM);
 };
@@ -223,19 +255,17 @@ struct FileCheckString {
       : Pat(P), Prefix(S), Loc(L) {}
 
   size_t Check(const SourceMgr &SM, StringRef Buffer, bool IsLabelScanMode,
-               size_t &MatchLen, StringMap<StringRef> &VariableTable,
-               FileCheckRequest &Req, std::vector<FileCheckDiag> *Diags) const;
+               size_t &MatchLen, FileCheckRequest &Req,
+               std::vector<FileCheckDiag> *Diags) const;
 
   bool CheckNext(const SourceMgr &SM, StringRef Buffer) const;
   bool CheckSame(const SourceMgr &SM, StringRef Buffer) const;
   bool CheckNot(const SourceMgr &SM, StringRef Buffer,
                 const std::vector<const FileCheckPattern *> &NotStrings,
-                StringMap<StringRef> &VariableTable,
                 const FileCheckRequest &Req,
                 std::vector<FileCheckDiag> *Diags) const;
   size_t CheckDag(const SourceMgr &SM, StringRef Buffer,
                   std::vector<const FileCheckPattern *> &NotStrings,
-                  StringMap<StringRef> &VariableTable,
                   const FileCheckRequest &Req,
                   std::vector<FileCheckDiag> *Diags) const;
 };
@@ -244,6 +274,7 @@ struct FileCheckString {
 /// use information from the request.
 class FileCheck {
   FileCheckRequest Req;
+  FileCheckPatternContext PatternContext;
 
 public:
   FileCheck(FileCheckRequest Req) : Req(Req) {}