Don't allow instructions/globals to use alignment > 2**29.

lib/Bitcode/NaCl/Reader/NaClBitcodeReader.h

Index: lib/Bitcode/NaCl/Reader/NaClBitcodeReader.h
diff --git a/lib/Bitcode/NaCl/Reader/NaClBitcodeReader.h b/lib/Bitcode/NaCl/Reader/NaClBitcodeReader.h
index 2ea3ede537487445e316d07ba13a815dfb2067ca..fa79eabc6f76d2fe1429d3d2751192775417eaac 100644
--- a/lib/Bitcode/NaCl/Reader/NaClBitcodeReader.h
+++ b/lib/Bitcode/NaCl/Reader/NaClBitcodeReader.h
@@ -16,6 +16,7 @@
 #define NACL_BITCODE_READER_H
 
 #include "llvm/ADT/DenseMap.h"
+#include "llvm/Analysis/NaCl/PNaClABIProps.h"
 #include "llvm/Analysis/NaCl/PNaClAllowedIntrinsics.h"
 #include "llvm/Bitcode/NaCl/NaClBitcodeHeader.h"
 #include "llvm/Bitcode/NaCl/NaClBitstreamReader.h"
@@ -27,6 +28,7 @@
 #include "llvm/IR/OperandTraits.h"
 #include "llvm/IR/Type.h"
 #include "llvm/IR/ValueHandle.h"
+#include "llvm/Support/raw_ostream.h"
 #include <vector>
 
 namespace llvm {
@@ -248,6 +250,11 @@ public:
   /// @returns true if an error occurred.
   std::error_code ParseBitcodeInto(Module *M);
 
+  /// Convert alignment exponent (i.e. power of two (or zero)) to the
+  /// corresponding alignment to use. If alignment is too large, it generates
+  /// an error message and returns corresponding error code.
+  std::error_code getAlignmentValue(uint64_t Exponent, unsigned &Alignment);
+
 private:
   // Returns false if Header is acceptable.
   bool AcceptHeader() const {
@@ -300,6 +307,27 @@ private:
     return getFnValueByID(ValNo);
   }
 
+  /// Convert alignment exponent (i.e. power of two (or zero)) to the
+  /// corresponding load/store alignment to use. If alignment is not
+  /// allowed for the load/store, it generates an error message and
+  /// returns the corresponding error code.
+  std::error_code getLoadStoreAlignmentValue(
+      uint64_t Exponent, const DataLayout *DL, Type *MemType,
+      const char *InstName, unsigned &Alignment) {
+    std::error_code EC = getAlignmentValue(Exponent, Alignment);
+    if (EC)
+      return EC;
+    if (!PNaClABIProps::isAllowedAlignment(DL, Alignment, MemType)) {
+      std::string Buffer;
+      raw_string_ostream StrBuf(Buffer);
+      StrBuf << "Invalid alignment for " << InstName << " of type "
+             << *MemType << ": " << Alignment;
+      return Error(InvalidValue, StrBuf.str());
+    }
+    // Successful!
+    return EC;
+  }
+
   /// \brief Create an (elided) cast instruction for basic block
   /// BBIndex.  Op is the type of cast.  V is the value to cast.  CT
   /// is the type to convert V to.  DeferInsertion defines whether the