Refactor preprocessing pass registration (#2468)

This commit refactors how preprocessing pass registration works,
inspired by LLVM's approach [0]. The basic idea is that every
preprocessing pass declares a static variable of type `RegisterPass` in
its source file that registers the pass with the
`PreprocessingPassRegistry` when starting the program. The registry is a
singleton that keeps track of all the available passes and allows other
code to create instances of the passes (note: previously the registry
itself was owning the passes but this is no longer the case). One of the
advantages of this solution is that we have a list of available passes
directly at the beginning of the program, which is useful for example
when parsing options.

As a side effect, this commit also fixes the SortInference pass, which
was expecting arguments other than the preprocessing pass context in its
constructor.

This commit is required for fixing dumping pre/post preprocessing
passes. It is also the ground work for allowing the user to specify a
preprocessing pipeline using command-line arguments.

[0] https://llvm.org/docs/WritingAnLLVMPass.html

1 files changed, 3 insertions, 0 deletions

diff --git a/src/preprocessing/passes/bv_ackermann.cpp b/src/preprocessing/passes/bv_ackermann.cpp
index 26785f15b..01fa70b61 100644
--- a/src/preprocessing/passes/bv_ackermann.cpp
+++ b/src/preprocessing/passes/bv_ackermann.cpp
@@ -24,6 +24,7 @@
 #include "preprocessing/passes/bv_ackermann.h"
 
 #include "options/bv_options.h"
+#include "preprocessing/preprocessing_pass_registry.h"
 #include "theory/bv/theory_bv_utils.h"
 
 using namespace CVC4;
@@ -213,6 +214,8 @@ PreprocessingPassResult BVAckermann::applyInternal(
   return PreprocessingPassResult::NO_CONFLICT;
 }
 
+static RegisterPass<BVAckermann> X("bv-ackermann");
+
 /* -------------------------------------------------------------------------- */
 
 }  // namespace passes