[Support] - Fix possible crash in match() of llvm::Regex.

[grimar]

Summary

Crash was possible if match() method
was called on object that was moved or object
created with empty constructor.

Testcases updated.

[grimar]

lib/Support/Regex.cpp

41 ↗

(On Diff #69977)

I moved it here because need to assign REG_BATPAT and dont want include "regex_impl.h" to .h file.

llvm/trunk/include/llvm/Support/Regex.h

public:
     /// Compiles the given regular expression \p Regex.
     Regex(StringRef Regex, unsigned Flags = NoFlags);
     Regex(const Regex &) = delete;
     Regex &operator=(Regex regex) {
       std::swap(preg, regex.preg);
       std::swap(error, regex.error);
       return *this;
     }
-    Regex(Regex &&regex) {
-      preg = regex.preg;
-      error = regex.error;
-      regex.preg = nullptr;
-    }
+    Regex(Regex &&regex);
     ~Regex();
 
     /// isValid - returns the error encountered during regex compilation, or
     /// matching, if any.
     bool isValid(std::string &Error);
 
     /// getNumMatches - In a valid regex, return the number of parenthesized
     /// matches it contains.  The number filled in by match will include this

llvm/trunk/lib/Support/Regex.cpp

if (Flags & IgnoreCase)
     flags |= REG_ICASE;
   if (Flags & Newline)
     flags |= REG_NEWLINE;
   if (!(Flags & BasicRegex))
     flags |= REG_EXTENDED;
   error = llvm_regcomp(preg, regex.data(), flags|REG_PEND);
 }
 
+Regex::Regex(Regex &&regex) {
+  preg = regex.preg;
+  error = regex.error;
+  regex.preg = nullptr;
+  regex.error = REG_BADPAT;
+}
+
 Regex::~Regex() {
   if (preg) {
     llvm_regfree(preg);
     delete preg;
   }
 }
 
 bool Regex::isValid(std::string &Error) {

 
 /// getNumMatches - In a valid regex, return the number of parenthesized
 /// matches it contains.
 unsigned Regex::getNumMatches() const {
   return preg->re_nsub;
 }
 
 bool Regex::match(StringRef String, SmallVectorImpl<StringRef> *Matches){
+  if (error)
+    return false;
+
   unsigned nmatch = Matches ? preg->re_nsub+1 : 0;
 
   // pmatch needs to have at least one element.
   SmallVector<llvm_regmatch_t, 8> pm;
   pm.resize(nmatch > 0 ? nmatch : 1);
   pm[0].rm_so = 0;
   pm[0].rm_eo = String.size();
 

llvm/trunk/unittests/Support/RegexTest.cpp

TEST_F(RegexTest, MoveConstruct) {
   EXPECT_TRUE(r2.match("916"));
 }
 
 TEST_F(RegexTest, MoveAssign) {
   Regex r1("^[0-9]+$");
   Regex r2("abc");
   r2 = std::move(r1);
   EXPECT_TRUE(r2.match("916"));
+  std::string Error;
+  EXPECT_FALSE(r1.isValid(Error));
 }
 
 TEST_F(RegexTest, NoArgConstructor) {
   std::string Error;
   Regex r1;
   EXPECT_FALSE(r1.isValid(Error));
   EXPECT_EQ("invalid regular expression", Error);
   r1 = Regex("abc");
   EXPECT_TRUE(r1.isValid(Error));
 }
 
+TEST_F(RegexTest, MatchInvalid) {
+  Regex r1;
+  std::string Error;
+  EXPECT_FALSE(r1.isValid(Error));
+  EXPECT_FALSE(r1.match("X"));
+}
+
 }