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Add generic support for hashing StringRef objects using the new hashing library. 

llvm-svn: 152003
This commit is contained in:
Chandler Carruth 2012-03-04 10:55:27 +00:00
parent 97b9359623
commit ca99ad3f0d
3 changed files with 30 additions and 0 deletions
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4
llvm/include/llvm/ADT/StringRef.h
View File

@ -19,6 +19,7 @@ namespace llvm {
template<typename T> template<typename T>
class SmallVectorImpl; class SmallVectorImpl;
class APInt; class APInt;
class hash_code;
/// StringRef - Represent a constant reference to a string, i.e. a character /// StringRef - Represent a constant reference to a string, i.e. a character
/// array and a length, which need not be null terminated. /// array and a length, which need not be null terminated.
@ -490,6 +491,9 @@ namespace llvm {
/// @} /// @}
/// \brief Compute a hash_code for a StringRef.
hash_code hash_value(StringRef S);
// StringRefs can be treated like a POD type. // StringRefs can be treated like a POD type.
template <typename T> struct isPodLike; template <typename T> struct isPodLike;
template <> struct isPodLike<StringRef> { static const bool value = true; }; template <> struct isPodLike<StringRef> { static const bool value = true; };

7
llvm/lib/Support/StringRef.cpp
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@ -10,6 +10,7 @@
#include "llvm/ADT/StringRef.h" #include "llvm/ADT/StringRef.h"
#include "llvm/ADT/APInt.h" #include "llvm/ADT/APInt.h"
#include "llvm/ADT/OwningPtr.h" #include "llvm/ADT/OwningPtr.h"
#include "llvm/ADT/Hashing.h"
#include "llvm/ADT/edit_distance.h" #include "llvm/ADT/edit_distance.h"
#include <bitset> #include <bitset>
@ -447,3 +448,9 @@ bool StringRef::getAsInteger(unsigned Radix, APInt &Result) const {
return false; return false;
} }
// Implementation of StringRef hashing.
hash_code llvm::hash_value(StringRef S) {
return hash_combine_range(S.begin(), S.end());
}

19
llvm/unittests/ADT/StringRefTest.cpp
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@ -9,6 +9,7 @@
#include "gtest/gtest.h" #include "gtest/gtest.h"
#include "llvm/ADT/StringRef.h" #include "llvm/ADT/StringRef.h"
#include "llvm/ADT/Hashing.h"
#include "llvm/ADT/SmallVector.h" #include "llvm/ADT/SmallVector.h"
#include "llvm/Support/raw_ostream.h" #include "llvm/Support/raw_ostream.h"
using namespace llvm; using namespace llvm;
@ -291,4 +292,22 @@ TEST(StringRefTest, Misc) {
EXPECT_EQ("hello", OS.str()); EXPECT_EQ("hello", OS.str());
} }
TEST(StringRefTest, Hashing) {
EXPECT_EQ(hash_value(std::string()), hash_value(StringRef()));
EXPECT_EQ(hash_value(std::string()), hash_value(StringRef("")));
std::string S = "hello world";
hash_code H = hash_value(S);
EXPECT_EQ(H, hash_value(StringRef("hello world")));
EXPECT_EQ(H, hash_value(StringRef(S)));
EXPECT_NE(H, hash_value(StringRef("hello worl")));
EXPECT_EQ(hash_value(std::string("hello worl")),
hash_value(StringRef("hello worl")));
EXPECT_NE(H, hash_value(StringRef("hello world ")));
EXPECT_EQ(hash_value(std::string("hello world ")),
hash_value(StringRef("hello world ")));
EXPECT_EQ(H, hash_value(StringRef("hello world\0")));
EXPECT_NE(hash_value(std::string("ello worl")),
hash_value(StringRef("hello world").slice(1, -1)));
}
} // end anonymous namespace } // end anonymous namespace