Commit c9a2cd0a authored by Bill Wendling's avatar Bill Wendling
Browse files

$ svn merge -c 113303 https://llvm.org/svn/llvm-project/llvm/trunk 

--- Merging r113303 into '.':
A    docs/CommandGuide/llvm-diff.pod
U    docs/CommandGuide/index.html

Log:
Add documentation for llvm-diff.

llvm-svn: 113310
parent 75e5c50b

llvm/docs/CommandGuide/index.html

+3 −0
Original line number Diff line number Diff line
@@ -72,6 +72,9 @@ options) arguments to the tool you are interested in.</p> 
<li><a href="/cmds/llvmc.html"><b>llvmc</b></a> -

    a generic customizable compiler driver</li>



<li><a href="/cmds/llvm-diff.html"><b>llvm-diff</b></a> -

    structurally compare two modules</li>



</ul>



</div>

llvm/docs/CommandGuide/llvm-diff.pod

0 → 100644
+53 −0
Original line number Diff line number Diff line 
=pod



=head1 NAME



llvm-diff - LLVM structural 'diff'



=head1 SYNOPSIS



B<llvm-diff> [I<options>] I<module 1> I<module 2> [I<global name ...>]



=head1 DESCRIPTION



B<llvm-diff> compares the structure of two LLVM modules, primarily

focusing on differences in function definitions.  Insignificant

differences, such as changes in the ordering of globals or in the

names of local values, are ignored.



An input module will be interpreted as an assembly file if its name

ends in '.ll';  otherwise it will be read in as a bitcode file.



If a list of global names is given, just the values with those names

are compared; otherwise, all global values are compared, and

diagnostics are produced for globals which only appear in one module

or the other.



B<llvm-diff> compares two functions by comparing their basic blocks,

beginning with the entry blocks.  If the terminators seem to match,

then the corresponding successors are compared; otherwise they are

ignored.  This algorithm is very sensitive to changes in control flow,

which tend to stop any downstream changes from being detected.



B<llvm-diff> is intended as a debugging tool for writers of LLVM

passes and frontends.  It does not have a stable output format.



=head1 EXIT STATUS



If B<llvm-diff> finds no differences between the modules, it will exit

with 0 and produce no output.  Otherwise it will exit with a non-zero

value.



=head1 BUGS



Many important differences, like changes in linkage or function

attributes, are not diagnosed.



Changes in memory behavior (for example, coalescing loads) can cause

massive detected differences in blocks.



=head1 AUTHORS



Maintained by the LLVM Team (L<http://llvm.org>).



=cut