Fixed off-by-one check

Author: tsarpaul

README.md

@@ -18,15 +18,15 @@ make
 3. Generate LLVM bytecode from your binary and run the StringObfuscator pass on it:
 ```
 clang -emit-llvm hello.c -c -o hello.bc
-opt -load-pass-plugin=<string-obfuscator-dir>/build/lib/LLVMStringObfuscator.so -passes="string-obfuscator-pass" < hello.bc -o out.bc
+opt -load-pass-plugin=./build/StringObfuscator/libLLVMStringObfuscator.so -passes="string-obfuscator-pass" < hello.bc -o out.bc
 llc out.bc -o out.s
 clang -static out.s -o out
 ```
 
 For Rust:
 ```
 rustc hello.rs --emit=llvm-bc -o hellor.bc
-opt -load-pass-plugin=/home/polka/Documents/Code/llvm-string-obfuscator/build/StringObfuscator/libLLVMStringObfuscator.so -passes="string-obfuscator-pass" < ~/Documents/Code/llvm-string-obfuscator/examples/hellor.bc -o out.bc
+opt -load-pass-plugin=./build/StringObfuscator/libLLVMStringObfuscator.so -passes="string-obfuscator-pass" < ./examples/hellor.bc -o out.bc
 llc out.bc -o out.s
 ruststd=$(basename $(ls /usr/lib/rustlib/x86_64-unknown-linux-gnu/lib/libstd*.so) | sed 's/lib//g' | sed 's/\.so//g')
 clang out.s -L/usr/lib/rustlib/x86_64-unknown-linux-gnu/lib -l$ruststd -o out

StringObfuscator/StringObfuscator.cpp

@@ -88,7 +88,7 @@ Function *createDecodeFunc(Module &M){
 	Builder->CreateStore(sub, stringaddr07);
 	auto *incdecptr = Builder->CreateGEP(stringaddr07, ConstantInt::get(IntegerType::get(Ctx, 64), 1), "incdecptr");
 	auto *var2 = Builder->CreateLoad(incdecptr, "var2");
-	auto cmp = Builder->CreateICmpEQ(var2, ConstantInt::get(IntegerType::get(Ctx, 8), 0), "cmp");
+	auto cmp = Builder->CreateICmpEQ(sub, ConstantInt::get(IntegerType::get(Ctx, 8), 0), "cmp");
 	Builder->CreateCondBr(cmp, BWhileEnd, BWhileBody);
 
 	// End block