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, 5 insertions, 3 deletions

diff --git a/src/preprocessing/passes/bv_to_bool.cpp b/src/preprocessing/passes/bv_to_bool.cpp
index bcfdeb24f..c6d98705c 100644
--- a/src/preprocessing/passes/bv_to_bool.cpp
+++ b/src/preprocessing/passes/bv_to_bool.cpp
@@ -21,11 +21,11 @@
 #include <vector>
 
 #include "expr/node.h"
-#include "theory/rewriter.h"
-#include "theory/theory.h"
-
+#include "preprocessing/preprocessing_pass_registry.h"
 #include "smt/smt_statistics_registry.h"
 #include "smt_util/node_visitor.h"
+#include "theory/rewriter.h"
+#include "theory/theory.h"
 
 namespace CVC4 {
 namespace preprocessing {
@@ -304,6 +304,8 @@ BVToBool::Statistics::~Statistics()
   smtStatisticsRegistry()->unregisterStat(&d_numTermsForcedLifted);
 }
 
+static RegisterPass<BVToBool> X("bv-to-bool");
+
 }  // passes
 }  // Preprocessing
 }  // CVC4