Use uint32_t for compilation unit index instead of uint16_t.

Change-Id: If89246e35c16a6b50942e0fe7dcc289234bbdfad
diff --git a/src/compiler_llvm/utils_llvm.h b/src/compiler_llvm/utils_llvm.h
index eb5fd53..5ad68d0 100644
--- a/src/compiler_llvm/utils_llvm.h
+++ b/src/compiler_llvm/utils_llvm.h
@@ -32,7 +32,7 @@
 #define VERIFY_LLVM_FUNCTION(func)
 #endif
 
-inline static std::string ElfFuncName(uint16_t idx) {
+inline static std::string ElfFuncName(uint32_t idx) {
   return StringPrintf("Art%u", static_cast<unsigned int>(idx));
 }