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Teach llvm-bcanalyzer to skip over the header we use on LLVM IR files.

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@68458 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner
2009-04-06 20:54:32 +00:00
parent 59d5f83b32
commit e2a466bfa9
3 changed files with 69 additions and 52 deletions
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47
lib/Bitcode/Reader/BitcodeReader.cpp
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@@ -1330,48 +1330,6 @@ bool BitcodeReader::ParseModule(const std::string &ModuleID) {
return Error("Premature end of bitstream");
}
/// SkipWrapperHeader - Some systems wrap bc files with a special header for
/// padding or other reasons. The format of this header is:
///
/// struct bc_header {
/// uint32_t Magic; // 0x0B17C0DE
/// uint32_t Version; // Version, currently always 0.
/// uint32_t BitcodeOffset; // Offset to traditional bitcode file.
/// uint32_t BitcodeSize; // Size of traditional bitcode file.
/// ... potentially other gunk ...
/// };
///
/// This function is called when we find a file with a matching magic number.
/// In this case, skip down to the subsection of the file that is actually a BC
/// file.
static bool SkipWrapperHeader(unsigned char *&BufPtr, unsigned char *&BufEnd) {
enum {
KnownHeaderSize = 4*4, // Size of header we read.
OffsetField = 2*4, // Offset in bytes to Offset field.
SizeField = 3*4 // Offset in bytes to Size field.
};
// Must contain the header!
if (BufEnd-BufPtr < KnownHeaderSize) return true;
unsigned Offset = ( BufPtr[OffsetField ] |
(BufPtr[OffsetField+1] << 8) |
(BufPtr[OffsetField+2] << 16) |
(BufPtr[OffsetField+3] << 24));
unsigned Size = ( BufPtr[SizeField ] |
(BufPtr[SizeField +1] << 8) |
(BufPtr[SizeField +2] << 16) |
(BufPtr[SizeField +3] << 24));
// Verify that Offset+Size fits in the file.
if (Offset+Size > unsigned(BufEnd-BufPtr))
return true;
BufPtr += Offset;
BufEnd = BufPtr+Size;
return false;
}
bool BitcodeReader::ParseBitcode() {
TheModule = 0;
@@ -1383,9 +1341,8 @@ bool BitcodeReader::ParseBitcode() {
// If we have a wrapper header, parse it and ignore the non-bc file contents.
// The magic number is 0x0B17C0DE stored in little endian.
if (BufPtr != BufEnd && BufPtr[0] == 0xDE && BufPtr[1] == 0xC0 &&
BufPtr[2] == 0x17 && BufPtr[3] == 0x0B)
if (SkipWrapperHeader(BufPtr, BufEnd))
if (isBitcodeWrapper(BufPtr, BufEnd))
if (SkipBitcodeWrapperHeader(BufPtr, BufEnd))
return Error("Invalid bitcode wrapper header");
Stream.init(BufPtr, BufEnd);