llvm-project/llvm/tools/llvm-dwp/DWPStringPool.h

57 lines
1.5 KiB
C++

#ifndef TOOLS_LLVM_DWP_DWPSTRINGPOOL
#define TOOLS_LLVM_DWP_DWPSTRINGPOOL
#include "llvm/ADT/DenseMap.h"
#include "llvm/MC/MCSection.h"
#include "llvm/MC/MCStreamer.h"
#include <cassert>
namespace llvm {
class DWPStringPool {
struct CStrDenseMapInfo {
static inline const char *getEmptyKey() {
return reinterpret_cast<const char *>(~static_cast<uintptr_t>(0));
}
static inline const char *getTombstoneKey() {
return reinterpret_cast<const char *>(~static_cast<uintptr_t>(1));
}
static unsigned getHashValue(const char *Val) {
assert(Val != getEmptyKey() && "Cannot hash the empty key!");
assert(Val != getTombstoneKey() && "Cannot hash the tombstone key!");
return (unsigned)hash_value(StringRef(Val));
}
static bool isEqual(const char *LHS, const char *RHS) {
if (RHS == getEmptyKey())
return LHS == getEmptyKey();
if (RHS == getTombstoneKey())
return LHS == getTombstoneKey();
return strcmp(LHS, RHS) == 0;
}
};
MCStreamer &Out;
MCSection *Sec;
DenseMap<const char *, uint32_t, CStrDenseMapInfo> Pool;
uint32_t Offset = 0;
public:
DWPStringPool(MCStreamer &Out, MCSection *Sec) : Out(Out), Sec(Sec) {}
uint32_t getOffset(const char *Str, unsigned Length) {
assert(strlen(Str) + 1 == Length && "Ensure length hint is correct");
auto Pair = Pool.insert(std::make_pair(Str, Offset));
if (Pair.second) {
Out.SwitchSection(Sec);
Out.EmitBytes(StringRef(Str, Length));
Offset += Length;
}
return Pair.first->second;
}
};
}
#endif