Bug 356077

Description Stefan Bylund 2011-08-29 09:48:58 EDT

Build Identifier: Eclipse 3.7.0 (Build id: I20110613-1736), CDT 8.0.0 (Build id: 201106081058)

Problem Description
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The Windows PE binary parser in CDT does not return global variables (which the ELF binary parser in CDT does). This bug report supercedes the old bug report 238081.

We encounter this problem in our Eclipse/CDT based product when we programatically use the Windows PE binary parser in CDT. The easiest way to reproduce this problem without writing code is to list the global variables in the Variables view in CDT, which may be configured to use the Windows PE binary parser.

Solution
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The Windows PE binary parser in CDT (org.eclipse.cdt.utils.coff.parser.PEBinaryObject) does not handle global variables correctly. When going through the symbol table it uses a filtering criteria that only filters out the symbols for functions but not for variables. The problem is that it filters the symbol table by looking for the symbol type field (e_type), and it only tries to keep the following types:

DT_PTR  01  Pointer to T
DT_FCN  10  Function returning T
DT_ARY  11  Array of T

While this works for functions in the symbol table, it does not work for variables because we can have variables that are neither pointers nor arrays and in fact GCC sets all the variables in the symbol table to be of the type

DT_NON  00  No derived type

Filtering for DT_NON as well is too weak because of its zero value (a lot of invalid entries would pass), so in order to have only the global variables added we have to filter for the storage class field (e_sclass) as well. If the symbol has the following storage class:

C_EXT  2  External (public) symbol

it is a global variable and we can add it to our list of global symbols.

A patch, relative CDT 8.0.0, for the org.eclipse.cdt.utils.coff.parser.PEBinaryObject and org.eclipse.cdt.utils.coff.Coff classes in the org.eclipse.cdt.core plugin is provided.


Reproducible: Always

Steps to Reproduce:
1. Make sure that you have a MinGW or Cygwin GCC/GDB installed.
2. Create an empty C project for executables and choose the toolchain MinGW GCC or Cygwin GCC.
3. Open the properties dialog on the newly created project and choose "C/C++ Build -> Settings -> Binary Parsers". Select the "PE Windows Parser" and deselect the "Cygwin PE Parser" (which works since it's only a wrapper around binutils and contains no symbol handling in its Java code).
4. Add the attached file test.c to the project and build it.
5. Create a "C/C++ Application" debug launch configuration and choose "Standard Create Process Launcher" as launcher.
6. Launch the debugger; you should now be in the main() function in test.c.
7. Single-step to one of the printf() lines in test.c.
8. Choose "Add Global Variables..." in the Variables view. Notice that the list of global variables is empty when at least "my_global_var" from test.c should be there.