Change all of the bytecode reader primitives to throw exceptions instead of

returning error codes.  Because they don't return an error code, they can
return the value read, which simplifies the code and makes the reader more
efficient (yaay!).

Also eliminate the special case code for little endian machines.

llvm-svn: 10871

1 files changed, 6 insertions, 14 deletions

diff --git a/llvm/lib/Bytecode/Reader/InstructionReader.cpp b/llvm/lib/Bytecode/Reader/InstructionReader.cpp
index 4beb2b0c11d..21a1490397a 100644
--- a/llvm/lib/Bytecode/Reader/InstructionReader.cpp
+++ b/llvm/lib/Bytecode/Reader/InstructionReader.cpp
@@ -36,9 +36,7 @@ namespace {
 
 RawInst::RawInst(const unsigned char *&Buf, const unsigned char *EndBuf,
                  std::vector<unsigned> &Args) {
-  unsigned Op, Typ;
-  if (read(Buf, EndBuf, Op)) 
-    throw std::string("Error reading from buffer.");
+  unsigned Op = read(Buf, EndBuf);
 
   // bits   Instruction format:        Common to all formats
   // --------------------------
@@ -85,25 +83,19 @@ RawInst::RawInst(const unsigned char *&Buf, const unsigned char *EndBuf,
     break;
   case 0:
     Buf -= 4;  // Hrm, try this again...
-    if (read_vbr(Buf, EndBuf, Opcode))
-      throw std::string("Error reading from buffer.");
+    Opcode = read_vbr_uint(Buf, EndBuf);
     Opcode >>= 2;
-    if (read_vbr(Buf, EndBuf, Type))
-      throw std::string("Error reading from buffer.");
+    Type = read_vbr_uint(Buf, EndBuf);
 
-    unsigned NumOperands;
-    if (read_vbr(Buf, EndBuf, NumOperands))
-      throw std::string("Error reading from buffer.");
+    unsigned NumOperands = read_vbr_uint(Buf, EndBuf);
     Args.resize(NumOperands);
 
     if (NumOperands == 0)
       throw std::string("Zero-argument instruction found; this is invalid.");
 
     for (unsigned i = 0; i != NumOperands; ++i)
-      if (read_vbr(Buf, EndBuf, Args[i])) 
-        throw std::string("Error reading from buffer");
-    if (align32(Buf, EndBuf))
-      throw std::string("Unaligned bytecode buffer.");
+      Args[i] = read_vbr_uint(Buf, EndBuf);
+    align32(Buf, EndBuf);
     break;
   }
 }