[llvm-branch-commits] [llvm] 5799fc7 - [llvm-reduce] Refactor global variable delta pass

Roman Lebedev via llvm-branch-commits llvm-branch-commits at lists.llvm.org
Sat Jan 2 14:50:31 PST 2021


Author: Roman Lebedev
Date: 2021-01-03T01:45:47+03:00
New Revision: 5799fc79c3fdbc81dd421afae38197009ad605c9

URL: https://github.com/llvm/llvm-project/commit/5799fc79c3fdbc81dd421afae38197009ad605c9
DIFF: https://github.com/llvm/llvm-project/commit/5799fc79c3fdbc81dd421afae38197009ad605c9.diff

LOG: [llvm-reduce] Refactor global variable delta pass

The limitation of the current pass that it skips initializer-less GV's
seems arbitrary, in all the reduced cases i (personally) looked at,
the globals weren't needed, yet they were kept.

So let's do two things:
1. allow reducing initializer-less globals
2. before reducing globals, reduce their initializers, much like we do function bodies

Added: 
    llvm/tools/llvm-reduce/deltas/ReduceGlobalVarInitializers.cpp
    llvm/tools/llvm-reduce/deltas/ReduceGlobalVarInitializers.h

Modified: 
    llvm/test/Reduce/remove-global-vars.ll
    llvm/tools/llvm-reduce/CMakeLists.txt
    llvm/tools/llvm-reduce/DeltaManager.h
    llvm/tools/llvm-reduce/deltas/ReduceGlobalVars.cpp
    llvm/tools/llvm-reduce/deltas/ReduceGlobalVars.h

Removed: 
    llvm/test/Reduce/Inputs/remove-global-vars.py


################################################################################
diff  --git a/llvm/test/Reduce/Inputs/remove-global-vars.py b/llvm/test/Reduce/Inputs/remove-global-vars.py
deleted file mode 100755
index 1ae8b0e6e76c..000000000000
--- a/llvm/test/Reduce/Inputs/remove-global-vars.py
+++ /dev/null
@@ -1,18 +0,0 @@
-#!/usr/bin/env python
-
-import sys
-
-InterestingVar = 0
-
-input = open(sys.argv[1], "r")
-for line in input:
-  i = line.find(';')
-  if i >= 0:
-    line = line[:i]
-  if line.startswith("@interesting = global") or "@interesting" in line:
-    InterestingVar += 1
-
-if InterestingVar == 4:
-  sys.exit(0) # interesting!
-
-sys.exit(1)

diff  --git a/llvm/test/Reduce/remove-global-vars.ll b/llvm/test/Reduce/remove-global-vars.ll
index 4fca4a1e6973..d078cad6b995 100644
--- a/llvm/test/Reduce/remove-global-vars.ll
+++ b/llvm/test/Reduce/remove-global-vars.ll
@@ -1,24 +1,47 @@
 ; Test that llvm-reduce can remove uninteresting Global Variables as well as
 ; their direct uses (which in turn are replaced with 'undef').
-;
-; RUN: llvm-reduce --test %python --test-arg %p/Inputs/remove-global-vars.py %s -o %t
-; RUN: cat %t | FileCheck -implicit-check-not=uninteresting %s
 
-; CHECK: @interesting = global
+; RUN: llvm-reduce --test FileCheck --test-arg --check-prefixes=CHECK-ALL,CHECK-INTERESTINGNESS --test-arg %s --test-arg --input-file %s -o %t
+; RUN: cat %t | FileCheck --check-prefixes=CHECK-ALL,CHECK-FINAL --implicit-check-not=uninteresting %s
+
+; CHECK-INTERESTINGNESS: @interesting = {{.*}}global i32{{.*}}, align 4
+; CHECK-INTERESTINGNESS: @interesting2 = global i32 0, align 4
+; CHECK-INTERESTINGNESS: @interesting3 = {{.*}}global i32{{.*}}, align 4
+
+; CHECK-FINAL: @interesting = external global i32, align 4
+; CHECK-FINAL: @interesting2 = global i32 0, align 4
+; CHECK-FINAL: @interesting3 = external global i32, align 4
 @interesting = global i32 0, align 4
+ at interesting2 = global i32 0, align 4
+ at interesting3 = external global i32, align 4
 @uninteresting = global i32 1, align 4
+ at uninteresting2 = external global i32, align 4
 
 define i32 @main() {
 entry:
   %0 = load i32, i32* @uninteresting, align 4
-  ; CHECK: store i32 undef, i32* @interesting, align 4
+
+  ; CHECK-INTERESTINGNESS: store i32 {{.*}}, i32* @interesting, align 4
+  ; CHECK-FINAL: store i32 undef, i32* @interesting, align 4
   store i32 %0, i32* @interesting, align 4
 
-  ; CHECK: load i32, i32* @interesting, align 4
+  ; CHECK-INTERESTINGNESS: store i32 {{.*}}, i32* @interesting3, align 4
+  ; CHECK-FINAL: store i32 undef, i32* @interesting3, align 4
+  store i32 %0, i32* @interesting3, align 4
+
+  ; CHECK-ALL: load i32, i32* @interesting, align 4
   %1 = load i32, i32* @interesting, align 4
   store i32 %1, i32* @uninteresting, align 4
 
-  ; CHECK: store i32 5, i32* @interesting, align 4
+  ; CHECK-ALL: load i32, i32* @interesting3, align 4
+  %2 = load i32, i32* @interesting3, align 4
+  store i32 %2, i32* @uninteresting2, align 4
+
+  ; CHECK-ALL: store i32 5, i32* @interesting, align 4
   store i32 5, i32* @interesting, align 4
+
+  ; CHECK-ALL: store i32 5, i32* @interesting3, align 4
+  store i32 5, i32* @interesting3, align 4
+
   ret i32 0
 }

diff  --git a/llvm/tools/llvm-reduce/CMakeLists.txt b/llvm/tools/llvm-reduce/CMakeLists.txt
index 3d635d178a71..b6db920e01bf 100644
--- a/llvm/tools/llvm-reduce/CMakeLists.txt
+++ b/llvm/tools/llvm-reduce/CMakeLists.txt
@@ -19,6 +19,7 @@ add_llvm_tool(llvm-reduce
   deltas/ReduceBasicBlocks.cpp
   deltas/ReduceFunctionBodies.cpp
   deltas/ReduceFunctions.cpp
+  deltas/ReduceGlobalVarInitializers.cpp
   deltas/ReduceGlobalVars.cpp
   deltas/ReduceInstructions.cpp
   deltas/ReduceMetadata.cpp

diff  --git a/llvm/tools/llvm-reduce/DeltaManager.h b/llvm/tools/llvm-reduce/DeltaManager.h
index 9c18da9793e7..18a6b0d363c4 100644
--- a/llvm/tools/llvm-reduce/DeltaManager.h
+++ b/llvm/tools/llvm-reduce/DeltaManager.h
@@ -19,6 +19,7 @@
 #include "deltas/ReduceBasicBlocks.h"
 #include "deltas/ReduceFunctionBodies.h"
 #include "deltas/ReduceFunctions.h"
+#include "deltas/ReduceGlobalVarInitializers.h"
 #include "deltas/ReduceGlobalVars.h"
 #include "deltas/ReduceInstructions.h"
 #include "deltas/ReduceMetadata.h"
@@ -34,6 +35,7 @@ inline void runDeltaPasses(TestRunner &Tester) {
   reduceFunctionBodiesDeltaPass(Tester);
   reduceFunctionsDeltaPass(Tester);
   reduceBasicBlocksDeltaPass(Tester);
+  reduceGlobalsInitializersDeltaPass(Tester);
   reduceGlobalsDeltaPass(Tester);
   reduceMetadataDeltaPass(Tester);
   reduceArgumentsDeltaPass(Tester);

diff  --git a/llvm/tools/llvm-reduce/deltas/ReduceGlobalVarInitializers.cpp b/llvm/tools/llvm-reduce/deltas/ReduceGlobalVarInitializers.cpp
new file mode 100644
index 000000000000..1128710f64c4
--- /dev/null
+++ b/llvm/tools/llvm-reduce/deltas/ReduceGlobalVarInitializers.cpp
@@ -0,0 +1,48 @@
+//===- 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 initializers of Global Variables in the provided Module.
+//
+//===----------------------------------------------------------------------===//
+
+#include "ReduceGlobalVarInitializers.h"
+#include "llvm/IR/Constants.h"
+
+using namespace llvm;
+
+/// Removes all the Initialized GVs that aren't inside the desired Chunks.
+static void extractGVsFromModule(std::vector<Chunk> ChunksToKeep,
+                                 Module *Program) {
+  Oracle O(ChunksToKeep);
+
+  // Drop initializers of out-of-chunk GVs
+  for (auto &GV : Program->globals())
+    if (GV.hasInitializer() && !O.shouldKeep())
+      GV.setInitializer(nullptr);
+}
+
+/// 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::reduceGlobalsInitializersDeltaPass(TestRunner &Test) {
+  outs() << "*** Reducing GVs initializers...\n";
+  int GVCount = countGVs(Test.getProgram());
+  runDeltaPass(Test, GVCount, extractGVsFromModule);
+}

diff  --git a/llvm/tools/llvm-reduce/deltas/ReduceGlobalVarInitializers.h b/llvm/tools/llvm-reduce/deltas/ReduceGlobalVarInitializers.h
new file mode 100644
index 000000000000..39288adce88c
--- /dev/null
+++ b/llvm/tools/llvm-reduce/deltas/ReduceGlobalVarInitializers.h
@@ -0,0 +1,21 @@
+//===- reduceGlobalsInitializersDeltaPass.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 initializers of Global Variables in the provided Module.
+//
+//===----------------------------------------------------------------------===//
+
+#include "Delta.h"
+#include "llvm/IR/Value.h"
+#include "llvm/Transforms/Utils/Cloning.h"
+
+namespace llvm {
+void reduceGlobalsInitializersDeltaPass(TestRunner &Test);
+} // namespace llvm

diff  --git a/llvm/tools/llvm-reduce/deltas/ReduceGlobalVars.cpp b/llvm/tools/llvm-reduce/deltas/ReduceGlobalVars.cpp
index dc8df7395e1f..4b184e5b3ead 100644
--- a/llvm/tools/llvm-reduce/deltas/ReduceGlobalVars.cpp
+++ b/llvm/tools/llvm-reduce/deltas/ReduceGlobalVars.cpp
@@ -7,7 +7,7 @@
 //===----------------------------------------------------------------------===//
 //
 // This file implements a function which calls the Generic Delta pass in order
-// to reduce initialized Global Variables in the provided Module.
+// to reduce Global Variables in the provided Module.
 //
 //===----------------------------------------------------------------------===//
 
@@ -17,7 +17,7 @@
 
 using namespace llvm;
 
-/// Removes all the Initialized GVs that aren't inside the desired Chunks.
+/// Removes all the GVs that aren't inside the desired Chunks.
 static void extractGVsFromModule(std::vector<Chunk> ChunksToKeep,
                                  Module *Program) {
   Oracle O(ChunksToKeep);
@@ -25,14 +25,14 @@ static void extractGVsFromModule(std::vector<Chunk> ChunksToKeep,
   // Get GVs inside desired chunks
   std::set<GlobalVariable *> GVsToKeep;
   for (auto &GV : Program->globals())
-    if (GV.hasInitializer() && O.shouldKeep())
+    if (O.shouldKeep())
       GVsToKeep.insert(&GV);
 
   // Delete out-of-chunk GVs and their uses
   std::vector<GlobalVariable *> ToRemove;
   std::vector<WeakVH> InstToRemove;
   for (auto &GV : Program->globals())
-    if (GV.hasInitializer() && !GVsToKeep.count(&GV)) {
+    if (!GVsToKeep.count(&GV)) {
       for (auto U : GV.users())
         if (auto *Inst = dyn_cast<Instruction>(U))
           InstToRemove.push_back(Inst);
@@ -54,7 +54,7 @@ static void extractGVsFromModule(std::vector<Chunk> ChunksToKeep,
     GV->eraseFromParent();
 }
 
-/// Counts the amount of initialized GVs and displays their
+/// Counts the amount of GVs and displays their
 /// respective name & index
 static int countGVs(Module *Program) {
   // TODO: Silence index with --quiet flag
@@ -62,8 +62,7 @@ static int countGVs(Module *Program) {
   outs() << "GlobalVariable Index Reference:\n";
   int GVCount = 0;
   for (auto &GV : Program->globals())
-    if (GV.hasInitializer())
-      outs() << "\t" << ++GVCount << ": " << GV.getName() << "\n";
+    outs() << "\t" << ++GVCount << ": " << GV.getName() << "\n";
   outs() << "----------------------------\n";
   return GVCount;
 }

diff  --git a/llvm/tools/llvm-reduce/deltas/ReduceGlobalVars.h b/llvm/tools/llvm-reduce/deltas/ReduceGlobalVars.h
index d4a870aded58..c8ba7eacb84c 100644
--- a/llvm/tools/llvm-reduce/deltas/ReduceGlobalVars.h
+++ b/llvm/tools/llvm-reduce/deltas/ReduceGlobalVars.h
@@ -7,7 +7,7 @@
 //===----------------------------------------------------------------------===//
 //
 // This file implements a function which calls the Generic Delta pass in order
-// to reduce initialized Global Variables in the provided Module.
+// to reduce Global Variables in the provided Module.
 //
 //===----------------------------------------------------------------------===//
 


        


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