Before, NativePDB uses scoped range as a workaround for value range, that causes
problems (e.g. a variable's value can only have one range, but usually a
variable's value is located at different address ranges, each at different
locations, in optimized build).
This patch let NativePDB switch to DWARFLocationList so a variable's value can
be described at multiple non-overlapped address ranges and each range maps to a
location.
Because overlapping ranges exists, here's peference when choosing ranges:
1. Always prefer whole value locations. Suppose a variable size is 8 bytes, one record is that for range [1, 5) first 4 bytes is at ecx, and another record is that for range [2, 8) the 8 bytes value is at rdx. This results: [1, 2) has first 4 bytes at ecx, [2, 8) has the whole value at rdx.
2. Always prefer the locations parsed later. Suppose first record is that for range [1, 5) value is at ecx, second record is that for range [2, 6) value is at eax. This results: [1, 2) -> ecx, [2, 6) -> eax.
Differential Revision: https://reviews.llvm.org/D130796
71d778f33e