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, 18 insertions, 37 deletions

diff --git a/llvm/lib/Bytecode/Reader/Reader.cpp b/llvm/lib/Bytecode/Reader/Reader.cpp
index 7a6fa875114..508fb7730a9 100644
--- a/llvm/lib/Bytecode/Reader/Reader.cpp
+++ b/llvm/lib/Bytecode/Reader/Reader.cpp
@@ -23,12 +23,6 @@
 #include "Support/StringExtras.h"
 using namespace llvm;
 
-static inline void ALIGN32(const unsigned char *&begin,
-                           const unsigned char *end) {
-  if (align32(begin, end))
-    throw std::string("Alignment error in buffer: read past end of block.");
-}
-
 unsigned BytecodeParser::getTypeSlot(const Type *Ty) {
   if (Ty->isPrimitiveType())
     return Ty->getPrimitiveID();
@@ -244,20 +238,16 @@ void BytecodeParser::ParseSymbolTable(const unsigned char *&Buf,
 
   while (Buf < EndBuf) {
     // Symtab block header: [num entries][type id number]
-    unsigned NumEntries, Typ;
-    if (read_vbr(Buf, EndBuf, NumEntries) ||
-        read_vbr(Buf, EndBuf, Typ)) throw Error_readvbr;
+    unsigned NumEntries = read_vbr_uint(Buf, EndBuf);
+    unsigned Typ = read_vbr_uint(Buf, EndBuf);
     const Type *Ty = getType(Typ);
     BCR_TRACE(3, "Plane Type: '" << *Ty << "' with " << NumEntries <<
                  " entries\n");
 
     for (unsigned i = 0; i != NumEntries; ++i) {
       // Symtab entry: [def slot #][name]
-      unsigned slot;
-      if (read_vbr(Buf, EndBuf, slot)) throw Error_readvbr;
-      std::string Name;
-      if (read(Buf, EndBuf, Name, false))  // Not aligned...
-        throw std::string("Failed reading symbol name.");
+      unsigned slot = read_vbr_uint(Buf, EndBuf);
+      std::string Name = read_str(Buf, EndBuf);
 
       Value *V = 0;
       if (Typ == Type::TypeTyID)
@@ -317,9 +307,7 @@ void BytecodeParser::materializeFunction(Function* F) {
 
   GlobalValue::LinkageTypes Linkage = GlobalValue::ExternalLinkage;
 
-  unsigned LinkageType;
-  if (read_vbr(Buf, EndBuf, LinkageType)) 
-    throw std::string("ParseFunction: Error reading from buffer.");
+  unsigned LinkageType = read_vbr_uint(Buf, EndBuf);
   if ((!hasExtendedLinkageSpecs && LinkageType > 3) ||
       ( hasExtendedLinkageSpecs && LinkageType > 4))
     throw std::string("Invalid linkage type for Function.");
@@ -382,7 +370,7 @@ void BytecodeParser::materializeFunction(Function* F) {
     BCR_TRACE(2, "} end block\n");
 
     // Malformed bc file if read past end of block.
-    ALIGN32(Buf, EndBuf);
+    align32(Buf, EndBuf);
   }
 
   // Make sure there were no references to non-existant basic blocks.
@@ -436,8 +424,7 @@ void BytecodeParser::ParseModuleGlobalInfo(const unsigned char *&Buf,
     throw std::string("Two ModuleGlobalInfo packets found!");
 
   // Read global variables...
-  unsigned VarType;
-  if (read_vbr(Buf, End, VarType)) throw Error_readvbr;
+  unsigned VarType = read_vbr_uint(Buf, End);
   while (VarType != Type::VoidTyID) { // List is terminated by Void
     unsigned SlotNo;
     GlobalValue::LinkageTypes Linkage;
@@ -476,17 +463,13 @@ void BytecodeParser::ParseModuleGlobalInfo(const unsigned char *&Buf,
     BCR_TRACE(2, "Global Variable of type: " << *Ty << "\n");
     insertValue(GV, SlotNo, ModuleValues);
 
-    if (VarType & 2) { // Does it have an initializer?
-      unsigned InitSlot;
-      if (read_vbr(Buf, End, InitSlot)) throw Error_readvbr;
-      GlobalInits.push_back(std::make_pair(GV, InitSlot));
-    }
-    if (read_vbr(Buf, End, VarType)) throw Error_readvbr;
+    if (VarType & 2)   // Does it have an initializer?
+      GlobalInits.push_back(std::make_pair(GV, read_vbr_uint(Buf, End)));
+    VarType = read_vbr_uint(Buf, End);
   }
 
   // Read the function objects for all of the functions that are coming
-  unsigned FnSignature;
-  if (read_vbr(Buf, End, FnSignature)) throw Error_readvbr;
+  unsigned FnSignature = read_vbr_uint(Buf, End);
   while (FnSignature != Type::VoidTyID) { // List is terminated by Void
     const Type *Ty = getType(FnSignature);
     if (!isa<PointerType>(Ty) ||
@@ -512,11 +495,11 @@ void BytecodeParser::ParseModuleGlobalInfo(const unsigned char *&Buf,
     //
     FunctionSignatureList.push_back(Func);
 
-    if (read_vbr(Buf, End, FnSignature)) throw Error_readvbr;
+    FnSignature = read_vbr_uint(Buf, End);
     BCR_TRACE(2, "Function of type: " << Ty << "\n");
   }
 
-  ALIGN32(Buf, End);
+  align32(Buf, End);
 
   // Now that the function signature list is set up, reverse it so that we can 
   // remove elements efficiently from the back of the vector.
@@ -530,8 +513,7 @@ void BytecodeParser::ParseModuleGlobalInfo(const unsigned char *&Buf,
 
 void BytecodeParser::ParseVersionInfo(const unsigned char *&Buf,
                                       const unsigned char *EndBuf) {
-  unsigned Version;
-  if (read_vbr(Buf, EndBuf, Version)) throw Error_readvbr;
+  unsigned Version = read_vbr_uint(Buf, EndBuf);
 
   // Unpack version number: low four bits are for flags, top bits = version
   Module::Endianness  Endianness;
@@ -596,7 +578,7 @@ void BytecodeParser::ParseModule(const unsigned char *Buf,
 
   // Read into instance variables...
   ParseVersionInfo(Buf, EndBuf);
-  ALIGN32(Buf, EndBuf);
+  align32(Buf, EndBuf);
 
   while (Buf < EndBuf) {
     const unsigned char *OldBuf = Buf;
@@ -633,7 +615,7 @@ void BytecodeParser::ParseModule(const unsigned char *Buf,
       break;
     }
     BCR_TRACE(1, "} end block\n");
-    ALIGN32(Buf, EndBuf);
+    align32(Buf, EndBuf);
   }
 
   // After the module constant pool has been read, we can safely initialize
@@ -666,9 +648,8 @@ void BytecodeParser::ParseBytecode(const unsigned char *Buf, unsigned Length,
   unsigned char *EndBuf = (unsigned char*)(Buf + Length);
 
   // Read and check signature...
-  unsigned Sig;
-  if (read(Buf, EndBuf, Sig) ||
-      Sig != ('l' | ('l' << 8) | ('v' << 16) | ('m' << 24)))
+  unsigned Sig = read(Buf, EndBuf);
+  if (Sig != ('l' | ('l' << 8) | ('v' << 16) | ('m' << 24)))
     throw std::string("Invalid bytecode signature!");
 
   TheModule = new Module(ModuleID);