llvm-6502/lib/Support/StreamableMemoryObject.cpp
Kaelyn Uhrain 44b2c82871 Don't assert when given an empty range.
llvm::RawMemoryObject handles empty ranges just fine, and the assert can
be triggered in the wild by e.g. invoking clang with a file that
included an empty pre-compiled header file when clang has been built
with assertions enabled. Without assertions enabled, clang will properly
report that the empty file is not a valid PCH.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@158769 91177308-0d34-0410-b5e6-96231b3b80d8
2012-06-20 00:16:40 +00:00

141 lines
4.5 KiB
C++

//===- StreamableMemoryObject.cpp - Streamable data interface -------------===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#include "llvm/Support/StreamableMemoryObject.h"
#include <cassert>
#include <cstring>
using namespace llvm;
namespace {
class RawMemoryObject : public StreamableMemoryObject {
public:
RawMemoryObject(const unsigned char *Start, const unsigned char *End) :
FirstChar(Start), LastChar(End) {
assert(LastChar >= FirstChar && "Invalid start/end range");
}
virtual uint64_t getBase() const { return 0; }
virtual uint64_t getExtent() const { return LastChar - FirstChar; }
virtual int readByte(uint64_t address, uint8_t* ptr) const;
virtual int readBytes(uint64_t address,
uint64_t size,
uint8_t* buf,
uint64_t* copied) const;
virtual const uint8_t *getPointer(uint64_t address, uint64_t size) const;
virtual bool isValidAddress(uint64_t address) const {
return validAddress(address);
}
virtual bool isObjectEnd(uint64_t address) const {return objectEnd(address);}
private:
const uint8_t* const FirstChar;
const uint8_t* const LastChar;
// These are implemented as inline functions here to avoid multiple virtual
// calls per public function
bool validAddress(uint64_t address) const {
return static_cast<ptrdiff_t>(address) < LastChar - FirstChar;
}
bool objectEnd(uint64_t address) const {
return static_cast<ptrdiff_t>(address) == LastChar - FirstChar;
}
RawMemoryObject(const RawMemoryObject&); // DO NOT IMPLEMENT
void operator=(const RawMemoryObject&); // DO NOT IMPLEMENT
};
int RawMemoryObject::readByte(uint64_t address, uint8_t* ptr) const {
if (!validAddress(address)) return -1;
*ptr = *((uint8_t *)(uintptr_t)(address + FirstChar));
return 0;
}
int RawMemoryObject::readBytes(uint64_t address,
uint64_t size,
uint8_t* buf,
uint64_t* copied) const {
if (!validAddress(address) || !validAddress(address + size - 1)) return -1;
memcpy(buf, (uint8_t *)(uintptr_t)(address + FirstChar), size);
if (copied) *copied = size;
return size;
}
const uint8_t *RawMemoryObject::getPointer(uint64_t address,
uint64_t size) const {
return FirstChar + address;
}
} // anonymous namespace
namespace llvm {
// If the bitcode has a header, then its size is known, and we don't have to
// block until we actually want to read it.
bool StreamingMemoryObject::isValidAddress(uint64_t address) const {
if (ObjectSize && address < ObjectSize) return true;
return fetchToPos(address);
}
bool StreamingMemoryObject::isObjectEnd(uint64_t address) const {
if (ObjectSize) return address == ObjectSize;
fetchToPos(address);
return address == ObjectSize && address != 0;
}
uint64_t StreamingMemoryObject::getExtent() const {
if (ObjectSize) return ObjectSize;
size_t pos = BytesRead + kChunkSize;
// keep fetching until we run out of bytes
while (fetchToPos(pos)) pos += kChunkSize;
return ObjectSize;
}
int StreamingMemoryObject::readByte(uint64_t address, uint8_t* ptr) const {
if (!fetchToPos(address)) return -1;
*ptr = Bytes[address + BytesSkipped];
return 0;
}
int StreamingMemoryObject::readBytes(uint64_t address,
uint64_t size,
uint8_t* buf,
uint64_t* copied) const {
if (!fetchToPos(address + size - 1)) return -1;
memcpy(buf, &Bytes[address + BytesSkipped], size);
if (copied) *copied = size;
return 0;
}
bool StreamingMemoryObject::dropLeadingBytes(size_t s) {
if (BytesRead < s) return true;
BytesSkipped = s;
BytesRead -= s;
return false;
}
void StreamingMemoryObject::setKnownObjectSize(size_t size) {
ObjectSize = size;
Bytes.reserve(size);
}
StreamableMemoryObject *getNonStreamedMemoryObject(
const unsigned char *Start, const unsigned char *End) {
return new RawMemoryObject(Start, End);
}
StreamableMemoryObject::~StreamableMemoryObject() { }
StreamingMemoryObject::StreamingMemoryObject(DataStreamer *streamer) :
Bytes(kChunkSize), Streamer(streamer), BytesRead(0), BytesSkipped(0),
ObjectSize(0), EOFReached(false) {
BytesRead = streamer->GetBytes(&Bytes[0], kChunkSize);
}
}