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/bool_to_bv.cpp b/src/preprocessing/passes/bool_to_bv.cpp
index 4c08d7e47..15b0ee678 100644
--- a/src/preprocessing/passes/bool_to_bv.cpp
+++ b/src/preprocessing/passes/bool_to_bv.cpp
@@ -20,6 +20,7 @@
 #include <vector>
 
 #include "expr/node.h"
+#include "preprocessing/preprocessing_pass_registry.h"
 #include "smt/smt_statistics_registry.h"
 #include "theory/rewriter.h"
 #include "theory/theory.h"
@@ -209,6 +210,8 @@ BoolToBV::Statistics::~Statistics()
   smtStatisticsRegistry()->unregisterStat(&d_numTermsForcedLowered);
 }
 
+static RegisterPass<BoolToBV> X("bool-to-bv");
+
 }  // namespace passes
 }  // namespace preprocessing
 }  // namespace CVC4