move TGSourceMgr class out of TableGen into libsupport.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@73842 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Support/SourceMgr.cpp

@@ -0,0 +1,107 @@
+//===- SourceMgr.cpp - Manager for Simple Source Buffers & Diagnostics ----===//
+//
+//                     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 SourceMgr class.  This class is used as a simple
+// substrate for diagnostics, #include handling, and other low level things for
+// simple parsers.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Support/SourceMgr.h"
+#include "llvm/Support/MemoryBuffer.h"
+#include "llvm/Support/raw_ostream.h"
+using namespace llvm;
+
+TGSourceMgr::~TGSourceMgr() {
+  while (!Buffers.empty()) {
+    delete Buffers.back().Buffer;
+    Buffers.pop_back();
+  }
+}
+
+/// FindBufferContainingLoc - Return the ID of the buffer containing the
+/// specified location, returning -1 if not found.
+int TGSourceMgr::FindBufferContainingLoc(TGLoc Loc) const {
+  for (unsigned i = 0, e = Buffers.size(); i != e; ++i)
+    if (Loc.getPointer() >= Buffers[i].Buffer->getBufferStart() &&
+        // Use <= here so that a pointer to the null at the end of the buffer
+        // is included as part of the buffer.
+        Loc.getPointer() <= Buffers[i].Buffer->getBufferEnd())
+      return i;
+  return -1;
+}
+
+/// FindLineNumber - Find the line number for the specified location in the
+/// specified file.  This is not a fast method.
+unsigned TGSourceMgr::FindLineNumber(TGLoc Loc, int BufferID) const {
+  if (BufferID == -1) BufferID = FindBufferContainingLoc(Loc);
+  assert(BufferID != -1 && "Invalid Location!");
+  
+  MemoryBuffer *Buff = getBufferInfo(BufferID).Buffer;
+  
+  // Count the number of \n's between the start of the file and the specified
+  // location.
+  unsigned LineNo = 1;
+  
+  const char *Ptr = Buff->getBufferStart();
+
+  for (; TGLoc::getFromPointer(Ptr) != Loc; ++Ptr)
+    if (*Ptr == '\n') ++LineNo;
+  return LineNo;
+}
+
+void TGSourceMgr::PrintIncludeStack(TGLoc IncludeLoc) const {
+  if (IncludeLoc == TGLoc()) return;  // Top of stack.
+  
+  int CurBuf = FindBufferContainingLoc(IncludeLoc);
+  assert(CurBuf != -1 && "Invalid or unspecified location!");
+
+  PrintIncludeStack(getBufferInfo(CurBuf).IncludeLoc);
+  
+  errs() << "Included from "
+         << getBufferInfo(CurBuf).Buffer->getBufferIdentifier()
+         << ":" << FindLineNumber(IncludeLoc, CurBuf) << ":\n";
+}
+
+
+void TGSourceMgr::PrintError(TGLoc ErrorLoc, const std::string &Msg) const {
+  raw_ostream &OS = errs();
+  
+  // First thing to do: find the current buffer containing the specified
+  // location.
+  int CurBuf = FindBufferContainingLoc(ErrorLoc);
+  assert(CurBuf != -1 && "Invalid or unspecified location!");
+  
+  PrintIncludeStack(getBufferInfo(CurBuf).IncludeLoc);
+  
+  MemoryBuffer *CurMB = getBufferInfo(CurBuf).Buffer;
+  
+  
+  OS << "Parsing " << CurMB->getBufferIdentifier() << ":"
+     << FindLineNumber(ErrorLoc, CurBuf) << ": ";
+  
+  OS << Msg << "\n";
+  
+  // Scan backward to find the start of the line.
+  const char *LineStart = ErrorLoc.getPointer();
+  while (LineStart != CurMB->getBufferStart() && 
+         LineStart[-1] != '\n' && LineStart[-1] != '\r')
+    --LineStart;
+  // Get the end of the line.
+  const char *LineEnd = ErrorLoc.getPointer();
+  while (LineEnd != CurMB->getBufferEnd() && 
+         LineEnd[0] != '\n' && LineEnd[0] != '\r')
+    ++LineEnd;
+  // Print out the line.
+  OS << std::string(LineStart, LineEnd) << "\n";
+  // Print out spaces before the caret.
+  for (const char *Pos = LineStart; Pos != ErrorLoc.getPointer(); ++Pos)
+    OS << (*Pos == '\t' ? '\t' : ' ');
+  OS << "^\n";
+}