[Bugpoint redesign] Added Pass to Remove Global Variables
Summary:
This pass tries to remove Global Variables, as well as their derived uses. For example if a variable `@x` is used by `%call1` and `%call2`, both these uses and the definition of `@x` are deleted. Moreover if `%call1` or `%call2` are used elsewhere those uses are also deleted, and so on recursively.
I'm still uncertain if this pass should remove derived uses, I'm open to suggestions.
Subscribers: mgorny, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D64176
> llvm-svn: 368918
llvm-svn: 369061
diff --git a/llvm/tools/llvm-reduce/CMakeLists.txt b/llvm/tools/llvm-reduce/CMakeLists.txt
index 8edc4f7..3ff7b7a 100644
--- a/llvm/tools/llvm-reduce/CMakeLists.txt
+++ b/llvm/tools/llvm-reduce/CMakeLists.txt
@@ -18,6 +18,7 @@
TestRunner.cpp
deltas/Delta.cpp
deltas/ReduceFunctions.cpp
+ deltas/ReduceGlobalVars.cpp
DEPENDS
intrinsics_gen
diff --git a/llvm/tools/llvm-reduce/DeltaManager.h b/llvm/tools/llvm-reduce/DeltaManager.h
index 28d1cd9..8033d76 100644
--- a/llvm/tools/llvm-reduce/DeltaManager.h
+++ b/llvm/tools/llvm-reduce/DeltaManager.h
@@ -14,11 +14,16 @@
#include "TestRunner.h"
#include "deltas/Delta.h"
#include "deltas/ReduceFunctions.h"
+#include "deltas/ReduceGlobalVars.h"
namespace llvm {
+// TODO: Add CLI option to run only specified Passes (for unit tests)
inline void runDeltaPasses(TestRunner &Tester) {
+ outs() << "Reducing functions...\n";
reduceFunctionsDeltaPass(Tester);
+ outs() << "Reducing GVs...\n";
+ reduceGlobalsDeltaPass(Tester);
// TODO: Implement the remaining Delta Passes
}
diff --git a/llvm/tools/llvm-reduce/deltas/ReduceGlobalVars.cpp b/llvm/tools/llvm-reduce/deltas/ReduceGlobalVars.cpp
new file mode 100644
index 0000000..15bb5a7
--- /dev/null
+++ b/llvm/tools/llvm-reduce/deltas/ReduceGlobalVars.cpp
@@ -0,0 +1,72 @@
+//===- ReduceGlobalVars.cpp - Specialized Delta Pass ----------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements a function which calls the Generic Delta pass in order
+// to reduce initialized Global Variables in the provided Module.
+//
+//===----------------------------------------------------------------------===//
+
+#include "ReduceGlobalVars.h"
+
+/// Removes all the Initialized GVs that aren't inside the desired Chunks.
+/// @returns the Module stripped of out-of-chunk GVs
+static void extractGVsFromModule(std::vector<Chunk> ChunksToKeep,
+ Module *Program) {
+ // Get GVs inside desired chunks
+ std::set<GlobalVariable *> GVsToKeep;
+ unsigned I = 0, GVCount = 0;
+ for (auto &GV : Program->globals())
+ if (GV.hasInitializer() && I < ChunksToKeep.size()) {
+ if (ChunksToKeep[I].contains(++GVCount))
+ GVsToKeep.insert(&GV);
+ if (GVCount == ChunksToKeep[I].end)
+ ++I;
+ }
+
+ // Delete out-of-chunk GVs and their uses
+ std::vector<GlobalVariable *> ToRemove;
+ std::vector<Instruction *> InstToRemove;
+ for (auto &GV : Program->globals())
+ if (GV.hasInitializer() && !GVsToKeep.count(&GV)) {
+ for (auto U : GV.users())
+ if (auto *Inst = dyn_cast<Instruction>(U))
+ InstToRemove.push_back(Inst);
+
+ GV.replaceAllUsesWith(UndefValue::get(GV.getType()));
+ ToRemove.push_back(&GV);
+ }
+
+ // Delete Instruction uses of unwanted GVs
+ for (auto *Inst : InstToRemove) {
+ Inst->replaceAllUsesWith(UndefValue::get(Inst->getType()));
+ Inst->eraseFromParent();
+ }
+
+ for (auto *GV : ToRemove)
+ GV->eraseFromParent();
+}
+
+/// Counts the amount of initialized GVs and displays their
+/// respective name & index
+static int countGVs(Module *Program) {
+ // TODO: Silence index with --quiet flag
+ outs() << "----------------------------\n";
+ outs() << "GlobalVariable Index Reference:\n";
+ int GVCount = 0;
+ for (auto &GV : Program->globals())
+ if (GV.hasInitializer())
+ outs() << "\t" << ++GVCount << ": " << GV.getName() << "\n";
+ outs() << "----------------------------\n";
+ return GVCount;
+}
+
+void llvm::reduceGlobalsDeltaPass(TestRunner &Test) {
+ outs() << "*** Reducing GVs...\n";
+ unsigned GVCount = countGVs(Test.getProgram());
+ runDeltaPass(Test, GVCount, extractGVsFromModule);
+}
diff --git a/llvm/tools/llvm-reduce/deltas/ReduceGlobalVars.h b/llvm/tools/llvm-reduce/deltas/ReduceGlobalVars.h
new file mode 100644
index 0000000..d4a870a
--- /dev/null
+++ b/llvm/tools/llvm-reduce/deltas/ReduceGlobalVars.h
@@ -0,0 +1,20 @@
+//===- ReduceGlobalVars.h - Specialized Delta Pass ------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This file implements a function which calls the Generic Delta pass in order
+// to reduce initialized Global Variables in the provided Module.
+//
+//===----------------------------------------------------------------------===//
+
+#include "Delta.h"
+#include "llvm/IR/Value.h"
+#include "llvm/Transforms/Utils/Cloning.h"
+
+namespace llvm {
+void reduceGlobalsDeltaPass(TestRunner &Test);
+} // namespace llvm