DWARFDebugAranges::Sort() calls std::stable_sort() over a set of address ranges
and then proceeds to collapse neighboring ranges together.
One problem with the current implementation is that it does an incomplete job.
When a pair of ranges are merged the next pair considered does not include the
just-merged range. IOW, three consecutive ranges are never collapsed into one.
Another problem is that for each range merged we are calling
std::vector::erase() which "shifts" all remaining elements of the vector by one
position on every merge. The end result (in the worst case) is a quadratic
algorithm -- not good when the input vector is large.
The following patch merges all consecutive ranges and removes the quadratic
behavior. The implementation uses an auxiliary vector of indices in order to
remember all ranges that can be dropped, then performs the coalescing of ranges
in a single pass.
Patch from Stephen Wilson with some minor modification by me.
llvm-svn: 129595
address space. I could see that this functionality would be useful,
but not in its current form (where the address space is ignored):
rather, we'd want to encode the address space into the parameter list
passed to operator new/operator delete somehow, which would require a
bunch more semantic analysis.
llvm-svn: 129593
dealing with address-space- and GC-qualified pointers. Previously,
these qualifiers were being treated just like cvr-qualifiers (in some
cases) or were completely ignored, leading to uneven behavior. For
example, const_cast would allow conversion between pointers to
different address spaces.
The new semantics are fairly simple: reinterpret_cast can be used to
explicitly cast between pointers to different address spaces
(including adding/removing addresss spaces), while
static_cast/dynamic_cast/const_cast do not tolerate any changes in the
address space. C-style casts can add/remove/change address spaces
through the reinterpret_cast mechanism. Other non-CVR qualifiers
(e.g., Objective-C GC qualifiers) work similarly.
As part of this change, I tweaked the "casts away constness"
diagnostic to use the term "casts away qualifiers". The term
"constness" actually comes from the C++ standard, despite the fact
that removing "volatile" also falls under that category. In Clang, we
also have restrict, address spaces, ObjC GC attributes, etc., so the
more general "qualifiers" is clearer.
llvm-svn: 129583
The transferValues() function can now handle both singly and multiply defined
values, as long as the resulting live range is known. Only rematerialized values
have their live range recomputed by extendRange().
The updateSSA() function can now insert PHI values in bulk across multiple
values in multiple target registers in one pass. The list of blocks received
from transferValues() is in layout order which seems to work well for the
iterative algorithm. Blocks from extendRange() are still in reverse BFS order,
but this function is used so rarely now that it doesn't matter.
llvm-svn: 129580
Change ELF systems to use CFI for producing the EH tables. This reduces the
size of the clang binary in Debug builds from 690MB to 679MB.
llvm-svn: 129571
is so broken that Sema can't form a declaration for it, don't bother
trying to parse the definition later. Fixes <rdar://problem/9221993>.
llvm-svn: 129547
instantiation), be sure to add the transformed declaration into the
current DeclContext. Also, remove the -Wuninitialized hack that works
around this bug. Fixes <rdar://problem/9200676>.
llvm-svn: 129544
Johnny Chen