Sink all InitializePasses.h includes

This file lists every pass in LLVM, and is included by Pass.h, which is
very popular. Every time we add, remove, or rename a pass in LLVM, it
caused lots of recompilation.

I found this fact by looking at this table, which is sorted by the
number of times a file was changed over the last 100,000 git commits
multiplied by the number of object files that depend on it in the
current checkout:
  recompiles    touches affected_files  header
  342380        95      3604    llvm/include/llvm/ADT/STLExtras.h
  314730        234     1345    llvm/include/llvm/InitializePasses.h
  307036        118     2602    llvm/include/llvm/ADT/APInt.h
  213049        59      3611    llvm/include/llvm/Support/MathExtras.h
  170422        47      3626    llvm/include/llvm/Support/Compiler.h
  162225        45      3605    llvm/include/llvm/ADT/Optional.h
  158319        63      2513    llvm/include/llvm/ADT/Triple.h
  140322        39      3598    llvm/include/llvm/ADT/StringRef.h
  137647        59      2333    llvm/include/llvm/Support/Error.h
  131619        73      1803    llvm/include/llvm/Support/FileSystem.h

Before this change, touching InitializePasses.h would cause 1345 files
to recompile. After this change, touching it only causes 550 compiles in
an incremental rebuild.

Reviewers: bkramer, asbirlea, bollu, jdoerfert

Differential Revision: https://reviews.llvm.org/D70211

1 files changed, 5 insertions, 1 deletions

diff --git a/llvm/lib/Analysis/LegacyDivergenceAnalysis.cpp b/llvm/lib/Analysis/LegacyDivergenceAnalysis.cpp
index 7de9d2cbfdd..e0dd14f91d0 100644
--- a/llvm/lib/Analysis/LegacyDivergenceAnalysis.cpp
+++ b/llvm/lib/Analysis/LegacyDivergenceAnalysis.cpp
@@ -64,10 +64,10 @@
 //
 //===----------------------------------------------------------------------===//
 
+#include "llvm/Analysis/LegacyDivergenceAnalysis.h"
 #include "llvm/ADT/PostOrderIterator.h"
 #include "llvm/Analysis/CFG.h"
 #include "llvm/Analysis/DivergenceAnalysis.h"
-#include "llvm/Analysis/LegacyDivergenceAnalysis.h"
 #include "llvm/Analysis/Passes.h"
 #include "llvm/Analysis/PostDominators.h"
 #include "llvm/Analysis/TargetTransformInfo.h"
@@ -75,6 +75,7 @@
 #include "llvm/IR/InstIterator.h"
 #include "llvm/IR/Instructions.h"
 #include "llvm/IR/Value.h"
+#include "llvm/InitializePasses.h"
 #include "llvm/Support/Debug.h"
 #include "llvm/Support/raw_ostream.h"
 #include <vector>
@@ -281,6 +282,9 @@ void DivergencePropagator::propagate() {
 
 // Register this pass.
 char LegacyDivergenceAnalysis::ID = 0;
+LegacyDivergenceAnalysis::LegacyDivergenceAnalysis() : FunctionPass(ID) {
+  initializeLegacyDivergenceAnalysisPass(*PassRegistry::getPassRegistry());
+}
 INITIALIZE_PASS_BEGIN(LegacyDivergenceAnalysis, "divergence",
                       "Legacy Divergence Analysis", false, true)
 INITIALIZE_PASS_DEPENDENCY(DominatorTreeWrapperPass)