Commit Graph

2 Commits

Author SHA1 Message Date
Diego Novillo 0915c047c2 Fix bug 19437 - Only add discriminators for DWARF 4 and above.
Summary:
This prevents the discriminator generation pass from triggering if
the DWARF version being used in the module is prior to 4.

Reviewers: echristo, dblaikie

CC: llvm-commits

Differential Revision: http://reviews.llvm.org/D3413

llvm-svn: 206507
2014-04-17 22:33:50 +00:00
Diego Novillo f5041ce558 Pass to emit DWARF path discriminators.
DWARF discriminators are used to distinguish multiple control flow paths
on the same source location. When this happens, instructions across
basic block boundaries will share the same debug location.

This pass detects this situation and creates a new lexical scope to one
of the two instructions. This lexical scope is a child scope of the
original and contains a new discriminator value. This discriminator is
then picked up from MCObjectStreamer::EmitDwarfLocDirective to be
written on the object file.

This fixes http://llvm.org/bugs/show_bug.cgi?id=18270.

llvm-svn: 202752
2014-03-03 20:06:11 +00:00