This commit introduces `BasicBlockID` as the unique identifier for a
`efa::BasicBlock` into the CFG. A `BasicBlockID` is defined by a
`MetaAddress` plus an incremental integer. This enables us to have
multiple instances of the same block in a single function, which is
particularly useful when inlining multiple times the same function.
Apart from this, the commit also does the following:
* It drops representing `MetaAddress`es a `structs` in the IR. This created
several issues related to ABI. We now represent them as strings.
* It defines more functions in `support.h`, instead of defining prototypes
by hand in `CodeGenerator.cpp` and the like. Specifically, `unknownPC`
and `raise_exception_helper`. We also introduce a C "constructor" for
`PlainMetaAddress`.
* It significantly reduces the API of `GeneratedCodeBasicInfo`, which
was supposed to be put on a diet since a long time. Specifically,
many jump target related methods have been moved to free functions in
`IRHelpers.h`. Also `GCBI::getSuccessors` has been pushed into its
only user, `PruneRetSuccessors`, to prevent further usage of a
deprecated API. In the future, it would be nice to drop it entirely.
* It introduces `efa::BasicBlock::InlinedFrom`.
* Introduce an enum to represent named argument indices for `newpc`.
This enables us to more effectively manipulate its argument list.
* It improves the verification and error reporting for
`efa::FunctionMetadata`.
* Update tests.
This commit is preliminary to another piece of work to improve the
generality of inlining beyond the simple "fake function" scenario, for
which the feature was originally conceived.
A logic issue existed in the Pipe, as it was mistakenly relying on
`IsolatedRoot` instead of the isolated function. That was breaking
things if those functions were to be removed. This issue has been
addressed by correcting the behaviour of the Pipe.
This change introduces some duplication but ensures an important
property of `tuple_tree_generate`d: data structures: all the leaves are
scalars. Previously, yield::Function was using efa::BasicBlock, making
things more difficult under certain conditions.
Specifically, we can rely on the fact that, when generating a visit to
the TupleTree, we know everything about all non-scalars.
The index of an element of a `SortedVector<yield::Tag>` was saved, but
`SortedVector` behaves like a set.
The issue has been fixed by creating a temporary `Tag` instead of trying
to keep a reference to an existing one.
Alessandro Di Federico