//===-- SourceFile.cpp - SourceFile implementation for the debugger -------===// // // The LLVM Compiler Infrastructure // // This file is distributed under the University of Illinois Open Source // License. See LICENSE.TXT for details. // //===----------------------------------------------------------------------===// // // This file implements the SourceFile class for the LLVM debugger. // //===----------------------------------------------------------------------===// #include "llvm/Debugger/SourceFile.h" #include "llvm/Support/MemoryBuffer.h" #include <cassert> using namespace llvm; static const char EmptyFile = 0; SourceFile::SourceFile(const std::string &fn, const GlobalVariable *Desc) : Filename(fn), Descriptor(Desc) { File.reset(MemoryBuffer::getFileOrSTDIN(fn)); // On error, return an empty buffer. if (File == 0) File.reset(MemoryBuffer::getMemBuffer(&EmptyFile, &EmptyFile)); } SourceFile::~SourceFile() { } /// calculateLineOffsets - Compute the LineOffset vector for the current file. /// void SourceFile::calculateLineOffsets() const { assert(LineOffset.empty() && "Line offsets already computed!"); const char *BufPtr = File->getBufferStart(); const char *FileStart = BufPtr; const char *FileEnd = File->getBufferEnd(); do { LineOffset.push_back(BufPtr-FileStart); // Scan until we get to a newline. while (BufPtr != FileEnd && *BufPtr != '\n' && *BufPtr != '\r') ++BufPtr; if (BufPtr != FileEnd) { ++BufPtr; // Skip over the \n or \r if (BufPtr[-1] == '\r' && BufPtr != FileEnd && BufPtr[0] == '\n') ++BufPtr; // Skip over dos/windows style \r\n's } } while (BufPtr != FileEnd); } /// getSourceLine - Given a line number, return the start and end of the line /// in the file. If the line number is invalid, or if the file could not be /// loaded, null pointers are returned for the start and end of the file. Note /// that line numbers start with 0, not 1. void SourceFile::getSourceLine(unsigned LineNo, const char *&LineStart, const char *&LineEnd) const { LineStart = LineEnd = 0; if (LineOffset.empty()) calculateLineOffsets(); // Asking for an out-of-range line number? if (LineNo >= LineOffset.size()) return; // Otherwise, they are asking for a valid line, which we can fulfill. LineStart = File->getBufferStart()+LineOffset[LineNo]; if (LineNo+1 < LineOffset.size()) LineEnd = File->getBufferStart()+LineOffset[LineNo+1]; else LineEnd = File->getBufferEnd(); // If the line ended with a newline, strip it off. while (LineEnd != LineStart && (LineEnd[-1] == '\n' || LineEnd[-1] == '\r')) --LineEnd; assert(LineEnd >= LineStart && "We somehow got our pointers swizzled!"); }