RFR(XS): 8079825: Uninitialised variable in hotspot/src/share/vm & cpu/x86/vm (runtime)

[David Holmes]

Looks good Calvin!

Thanks,
David

On 17/07/2015 3:09 AM, Calvin Cheung wrote:
> This is for fixing some warnings about uninitialized variables reported
> by our internal code analysis tool.
>
> JBS: https://bugs.openjdk.java.net/browse/JDK-8079825
>        (this is a confidential bug)
>
> webrev: http://cr.openjdk.java.net/~ccheung/8079825/webrev.00/
>
> [1] Uninitialised pointer localvariable_type_table_start may be used as
> argument
> 8 when calling ClassFileParser::copy_localvariable_table at line 2465 of
> hotspot/src/share/vm/classfile/classFileParser.cpp in function
> ClassFileParser::parse_method
>
> Similar warning message for the other 3 local variables.
>
> The fix in classFileParser.cpp is for initializing the following
> variables to NULL:
>      localvariable_table_length,
>      localvariable_table_start,
>      localvariable_type_table_length,
>      localvariable_type_table_start
>
> They may not be defined if the execution path goes through the if block
> at line 2137:
>          if (LoadLineNumberTables &&
>              _cp->symbol_at(code_attribute_name_index) ==
> vmSymbols::tag_line_number_table()) {
>            // Parse and compress line number table
>            parse_linenumber_table(code_attribute_length, code_length,
>              &linenumber_table, CHECK_(nullHandle));
>
> [2] Uninitialised pointer rf may be used as argument 1 when calling
> RFrame::set_distance at line 96 of
> hotspot/src/share/vm/runtime/rframe.cpp in
> function RFrame::new_RFrame
>
> The fix in rframe.cpp is for initializing the rf to NULL.
>
> It isn't being initialized if the execution path goes to the else block:
>      } else {
>        assert(false, "Unhandled frame type");
>      }
>
> the assert is only for debug build.
>
> Testing:
>     JPRT
>    Aurora adhoc run including vm.quick on linux, windows (32- and
> 64-bit), and solaris sparc and x64
>
> Thanks in advance for your review.
>
> Calvin
>