Moved to lib/Bytecode/Archive in preparation for re-write.

llvm-svn: 17742

1 files changed, 194 insertions, 0 deletions

diff --git a/llvm/lib/Bytecode/Archive/ArchiveReader.cpp b/llvm/lib/Bytecode/Archive/ArchiveReader.cpp
new file mode 100644
index 00000000000..b39dd7e5840
--- /dev/null
+++ b/llvm/lib/Bytecode/Archive/ArchiveReader.cpp
@@ -0,0 +1,194 @@
+//===- lib/Archive/ArchiveReader.cpp - Read LLVM archive files ------------===//
+// 
+//                     The LLVM Compiler Infrastructure
+//
+// This file was developed by the LLVM research group and is distributed under
+// the University of Illinois Open Source License. See LICENSE.TXT for details.
+// 
+//===----------------------------------------------------------------------===//
+//
+// This file implements the ReadArchiveFile interface, which allows a linker to
+// read all of the LLVM bytecode files contained in a .a file.  This file
+// understands the standard system .a file format.  This can only handle the .a
+// variant prevalent on Linux systems so far, but may be extended.  See
+// information in this source file for more information:
+//   http://sources.redhat.com/cgi-bin/cvsweb.cgi/src/bfd/archive.c?cvsroot=src
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Bytecode/Reader.h"
+#include "llvm/Module.h"
+#include "llvm/Support/FileUtilities.h"
+#include <cstdlib>
+#include <iostream>
+using namespace llvm;
+
+namespace {
+  struct ar_hdr {
+    char name[16];
+    char date[12];
+    char uid[6];
+    char gid[6];
+    char mode[8];
+    char size[10];
+    char fmag[2];          // Always equal to '`\n'
+  };
+
+  enum ObjectType {
+    UserObject,            // A user .o/.bc file
+    Unknown,               // Unknown file, just ignore it
+    SVR4LongFilename,      // a "//" section used for long file names
+    ArchiveSymbolTable,    // Symbol table produced by ranlib.
+  };
+}
+
+/// getObjectType - Determine the type of object that this header represents.
+/// This is capable of parsing the variety of special sections used for various
+/// purposes.
+///
+static enum ObjectType getObjectType(ar_hdr *H, std::string MemberName,
+                                     unsigned char *MemberData, unsigned Size) {
+  // Check for sections with special names...
+  if (MemberName == "__.SYMDEF       " || MemberName == "__.SYMDEF SORTED")
+    return ArchiveSymbolTable;
+  else if (MemberName == "//              ")
+    return SVR4LongFilename;
+
+  // Check to see if it looks like an llvm object file...
+  if (Size >= 4 && !memcmp(MemberData, "llvm", 4))
+    return UserObject;
+
+  if (Size >= 4 && !memcmp(MemberData, "llvc", 4))
+    return UserObject;
+
+  return Unknown;
+}
+
+static inline bool Error(std::string *ErrorStr, const char *Message) {
+  if (ErrorStr) *ErrorStr = Message;
+  return true;
+}
+
+static bool ParseSymbolTableSection(unsigned char *Buffer, unsigned Size,
+                                    std::string *S) {
+  // Currently not supported (succeeds without doing anything)
+  return false;
+}
+
+static bool ReadArchiveBuffer(const std::string &ArchiveName,
+                              unsigned char *Buffer, unsigned Length,
+                              std::vector<Module*> &Objects,
+                              std::string *ErrorStr) {
+  if (Length < 8 || memcmp(Buffer, "!<arch>\n", 8))
+    return Error(ErrorStr, "signature incorrect for an archive file!");
+  Buffer += 8;  Length -= 8; // Skip the magic string.
+
+  std::vector<char> LongFilenames;
+
+  while (Length >= sizeof(ar_hdr)) {
+    ar_hdr *Hdr = (ar_hdr*)Buffer;
+    unsigned SizeFromHeader = atoi(Hdr->size);
+    if (SizeFromHeader + sizeof(ar_hdr) > Length)
+      return Error(ErrorStr, "invalid record length in archive file!");
+
+    unsigned char *MemberData = Buffer + sizeof(ar_hdr);
+    unsigned MemberSize = SizeFromHeader;
+    // Get name of archive member.
+    char *startp = Hdr->name;
+    char *endp = (char *) memchr (startp, '/', sizeof(ar_hdr));
+    if (memcmp (Hdr->name, "#1/", 3) == 0) {
+      // 4.4BSD/MacOSX long filenames are abbreviated as "#1/L", where L is an
+      // ASCII-coded decimal number representing the length of the name buffer,
+      // which is prepended to the archive member's contents.
+      unsigned NameLength = atoi (&Hdr->name[3]);
+      startp = (char *) MemberData;
+      endp = startp + NameLength;
+      MemberData += NameLength;
+      MemberSize -= NameLength;
+    } else if (startp == endp && isdigit (Hdr->name[1])) {
+      // SVR4 long filenames are abbreviated as "/I", where I is
+      // an ASCII-coded decimal index into the LongFilenames vector.
+      unsigned NameIndex = atoi (&Hdr->name[1]);
+      assert (LongFilenames.size () > NameIndex
+              && "SVR4-style long filename for archive member not found");
+      startp = &LongFilenames[NameIndex];
+      endp = strchr (startp, '/');
+    } else if (startp == endp && Hdr->name[1] == '/') {
+      // This is for the SVR4 long filename table (there might be other
+      // names starting with // but I don't know about them). Make sure that
+      // getObjectType sees it.
+      endp = &Hdr->name[sizeof (Hdr->name)];
+    }
+    if (!endp) {
+      // 4.4BSD/MacOSX *short* filenames are not guaranteed to have a
+      // terminator. Start at the end of the field and backtrack over spaces.
+      endp = startp + sizeof(Hdr->name);
+      while (endp[-1] == ' ')
+        --endp;
+    }
+    std::string MemberName (startp, endp);
+    std::string FullMemberName = ArchiveName + "(" + MemberName + ")";
+
+    switch (getObjectType(Hdr, MemberName, MemberData, MemberSize)) {
+    case SVR4LongFilename:
+      // If this is a long filename section, read all of the file names into the
+      // LongFilenames vector.
+      LongFilenames.assign (MemberData, MemberData + MemberSize);
+      break;
+    case UserObject: {
+      Module *M = ParseBytecodeBuffer(MemberData, MemberSize,
+                                      FullMemberName, ErrorStr);
+      if (!M) return true;
+      Objects.push_back(M);
+      break;
+    }
+    case ArchiveSymbolTable:
+      if (ParseSymbolTableSection(MemberData, MemberSize, ErrorStr))
+        return true;
+      break;
+    default:
+      std::cerr << "ReadArchiveBuffer: WARNING: Skipping unknown file: "
+                << FullMemberName << "\n";
+      break;   // Just ignore unknown files.
+    }
+
+    // Round SizeFromHeader up to an even number...
+    SizeFromHeader = (SizeFromHeader+1)/2*2;
+    Buffer += sizeof(ar_hdr)+SizeFromHeader;   // Move to the next entry
+    Length -= sizeof(ar_hdr)+SizeFromHeader;
+  }
+
+  return Length != 0;
+}
+
+
+// ReadArchiveFile - Read bytecode files from the specified .a file, returning
+// true on error, or false on success.  This does not support reading files from
+// standard input.
+//
+bool llvm::ReadArchiveFile(const std::string &Filename,
+                           std::vector<Module*> &Objects,std::string *ErrorStr){
+  unsigned Length;
+
+    // mmap in the file all at once...
+  unsigned char *Buffer = 
+     (unsigned char*)ReadFileIntoAddressSpace(Filename, Length);
+  if (Buffer == 0) {
+    if (ErrorStr) *ErrorStr = "Error reading file '" + Filename + "'!";
+    return true;
+  }
+  
+  // Parse the archive files we mmap'ped in
+  bool Result = ReadArchiveBuffer(Filename, Buffer, Length, Objects, ErrorStr);
+  
+  // Unmmap the archive...
+  UnmapFileFromAddressSpace(Buffer, Length);
+
+  if (Result)    // Free any loaded objects
+    while (!Objects.empty()) {
+      delete Objects.back();
+      Objects.pop_back();
+    }
+  
+  return Result;
+}