1 =pod 2 3 =head1 NAME 4 5 llvm-diff - LLVM structural 'diff' 6 7 =head1 SYNOPSIS 8 9 B<llvm-diff> [I<options>] I<module 1> I<module 2> [I<global name ...>] 10 11 =head1 DESCRIPTION 12 13 B<llvm-diff> compares the structure of two LLVM modules, primarily 14 focusing on differences in function definitions. Insignificant 15 differences, such as changes in the ordering of globals or in the 16 names of local values, are ignored. 17 18 An input module will be interpreted as an assembly file if its name 19 ends in '.ll'; otherwise it will be read in as a bitcode file. 20 21 If a list of global names is given, just the values with those names 22 are compared; otherwise, all global values are compared, and 23 diagnostics are produced for globals which only appear in one module 24 or the other. 25 26 B<llvm-diff> compares two functions by comparing their basic blocks, 27 beginning with the entry blocks. If the terminators seem to match, 28 then the corresponding successors are compared; otherwise they are 29 ignored. This algorithm is very sensitive to changes in control flow, 30 which tend to stop any downstream changes from being detected. 31 32 B<llvm-diff> is intended as a debugging tool for writers of LLVM 33 passes and frontends. It does not have a stable output format. 34 35 =head1 EXIT STATUS 36 37 If B<llvm-diff> finds no differences between the modules, it will exit 38 with 0 and produce no output. Otherwise it will exit with a non-zero 39 value. 40 41 =head1 BUGS 42 43 Many important differences, like changes in linkage or function 44 attributes, are not diagnosed. 45 46 Changes in memory behavior (for example, coalescing loads) can cause 47 massive detected differences in blocks. 48 49 =head1 AUTHORS 50 51 Maintained by the LLVM Team (L<http://llvm.org/>). 52 53 =cut 54
