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Rafael Espindola c2966a3ac7 Remove getRelocationAddress.

Originally added in r139314.

Back then it didn't actually get the address, it got whatever value the
relocation used: address or offset.

The values in different object formats are:

* MachO: Always an offset.
* COFF: Always an address, but when talking about the virtual address of
sections it says: "for simplicity, compilers should set this to zero".
* ELF: An offset for .o files and and address for .so files. In the case of the
.so, the relocation in not linked to any section (sh_info is 0). We can't
really compute an offset.

Some API mappings would be:

* Use getAddress for everything. It would be quite cumbersome. To compute the
address elf has to follow sh_info, which can be corrupted and therefore the
method has to return an ErrorOr. The address of the section is also the same
for every relocation in a section, so we shouldn't have to check the error
and fetch the value for every relocation.

* Use a getValue and make it up to the user to know what it is getting.

* Use a getOffset and:
* Assert for dynamic ELF objects. That is a very peculiar case and it is
probably fair to ask any tool that wants to support it to use ELF.h. The
only tool we have that reads those (llvm-readobj) already does that. The
only other use case I can think of is a dynamic linker.
* Check that COFF .obj files have sections with zero virtual address spaces. If
it turns out that some assembler/compiler produces these, we can change
COFFObjectFile::getRelocationOffset to subtract it. Given COFF format,
this can be done without the need for ErrorOr.

The getRelocationAddress method was never implemented for COFF. It also
had exactly one use in a very peculiar case: a shortcut for adding the
section value to a pcrel reloc on MachO.

Given that, I don't expect that there is any use out there of the C API. If
that is not the case, let me know and I will add it back with the implementation
inlined and do a proper deprecation.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@241450 91177308-0d34-0410-b5e6-96231b3b80d8

2015-07-06 14:55:37 +00:00

llvm

README.txt

This directory contains Python bindings for LLVM's C library.

The bindings are currently a work in progress and are far from complete.
Use at your own risk.

Developer Info
==============

The single Python package is "llvm." Modules inside this package roughly
follow the names of the modules/headers defined by LLVM's C API.

Testing
-------

All test code is location in llvm/tests. Tests are written as classes
which inherit from llvm.tests.base.TestBase, which is a convenience base
class that provides common functionality.

Tests can be executed by installing nose:

    pip install nosetests

Then by running nosetests:

    nosetests

To see more output:

    nosetests -v

To step into the Python debugger while running a test, add the following
to your test at the point you wish to enter the debugger:

    import pdb; pdb.set_trace()

Then run nosetests:

    nosetests -s -v

You should strive for high code coverage. To see current coverage:

    pip install coverage
    nosetests --with-coverage --cover-html

Then open cover/index.html in your browser of choice to see the code coverage.

Style Convention
----------------

All code should pass PyFlakes. First, install PyFlakes:

    pip install pyflakes

Then at any time run it to see a report:

    pyflakes .

Eventually we'll provide a Pylint config file. In the meantime, install
Pylint:

    pip install pylint

And run:

    pylint llvm

And try to keep the number of violations to a minimum.