b40c9ee2b2
With this change, all instances Symbol are stored in class Symbols. Scope.symbols_, which used to own the symbol memory, now maps names to Symbol* instead. This causes a bunch of reference-to-pointer changes because of the change in type of key-value pairs. It also requires a default constructor for Symbol, which means owner_ can't be a reference. Symbols manages Symbol instances by allocating a block of them at a time and returning the next one when needed. They are never freed. The reason for the change is that there are a few cases where we need to have a two symbols with the same name, so they can't both live in the map in Scope. Those are: 1. When there is an erroneous redeclaration of a name we may delete the first symbol and replace it with a new one. If we have saved a pointer to the first one it is now dangling. This can be seen by running `f18 -fdebug-dump-symbols -fparse-only test/semantics/resolve19.f90` under valgrind. Subroutine s is declared twice: each results in a scope that contains a pointer back to the symbol for the subroutine. After the second symbol for s is created the first is gone so the pointer in the scope is invalid. 2. A generic and one of its specifics can have the same name. We currently handle that by moving the symbol for the specific into a unique_ptr in the generic. So in that case the symbol is owned by another symbol instead of by the scope. It is simpler if we only have to deal with moving the raw pointer around. 3. A generic and a derived type can have the same name. This case isn't handled yet, but it can be done like flang-compiler/f18#2 above. It's more complicated because the derived type and the generic can be declared in either order. Original-commit: flang-compiler/f18@55a68cf023 Reviewed-on: https://github.com/flang-compiler/f18/pull/107 |
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common | ||
evaluate | ||
parser | ||
semantics | ||
CMakeLists.txt |