The existing spirv-opt `DebugInfoManager::AddDebugValueForDecl()` sets
the scope and line info of the new added DebugValue using the scope and
line of DebugDeclare. This is wrong because only a single DebugDeclare
must exist under a scope while we have to add DebugValue for all the
places where the variable's value is updated. Therefore, we have to set
the scope and line of DebugValue based on the places of the variable
updates.
This bug makes
https://github.com/google/amber/blob/main/tests/cases/debugger_hlsl_shadowed_vars.amber
fail. This commit fixes the bug.
When we copy the loop body to unroll it, we have to copy its
instructions but DebugDeclare or DebugValue used for the declaration
i.e., DebugValue with Deref must not be copied and only the first block
can contain those instructions.
We need an analysis for OpenCL.DebugInfo.100 extension instructions such
as a map between function id and its DebugFunction. This commit add an
analysis for it.