[llvm-reduce] add ReduceAttribute delta pass

Summary:
The output from llvm-reduce still has significantly more attributes than
bugpoint does.  Teach llvm-reduce to remove attributes.

Reviewers: diegotf, dblaikie, george.burgess.iv

Subscribers: mgorny, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D73853

diff --git a/llvm/test/Reduce/Inputs/remove-attributes.py b/llvm/test/Reduce/Inputs/remove-attributes.py
new file mode 100755 (executable)
index 0000000..af76dd4
--- /dev/null
+++ b/llvm/test/Reduce/Inputs/remove-attributes.py
@@ -0,0 +1,7 @@
+import sys
+
+for line in open(sys.argv[1], "r"):
+  if "use-soft-float" in line:
+    sys.exit(0) # Interesting!
+
+sys.exit(1)

diff --git a/llvm/test/Reduce/remove-attributes.ll b/llvm/test/Reduce/remove-attributes.ll
new file mode 100644 (file)
index 0000000..4dc6ea1
--- /dev/null
+++ b/llvm/test/Reduce/remove-attributes.ll
@@ -0,0 +1,16 @@
+; Test that llvm-reduce can remove uninteresting attributes.
+;
+; RUN: rm -rf %t
+; RUN: llvm-reduce --test %python --test-arg %p/Inputs/remove-attributes.py %s -o %t
+; RUN: cat %t | FileCheck  %s
+
+define void @a() #0 {
+  ret void
+}
+define void @b() #1 {
+  ret void
+}
+
+; CHECK: attributes #0 = { "use-soft-float"="false" }
+attributes #0 = { norecurse noreturn nounwind readnone uwtable "correctly-rounded-divide-sqrt-fp-math"="false" "disable-tail-calls"="false" "frame-pointer"="none" "less-precise-fpmad"="false" "min-legal-vector-width"="0" "no-infs-fp-math"="false" "no-jump-tables"="false" "no-nans-fp-math"="false" "no-signed-zeros-fp-math"="false" "no-trapping-math"="false" "patchable-function-entry"="2" "stack-protector-buffer-size"="8" "target-cpu"="x86-64" "target-features"="+cx8,+fxsr,+mmx,+sse,+sse2,+x87" "unsafe-fp-math"="false" "use-soft-float"="false" }
+attributes #1 = { norecurse }

diff --git a/llvm/tools/llvm-reduce/CMakeLists.txt b/llvm/tools/llvm-reduce/CMakeLists.txt
index 48de0ff..359626f 100644 (file)
--- a/llvm/tools/llvm-reduce/CMakeLists.txt
+++ b/llvm/tools/llvm-reduce/CMakeLists.txt
@@ -14,12 +14,13 @@ add_llvm_tool(llvm-reduce
   llvm-reduce.cpp
   TestRunner.cpp
   deltas/Delta.cpp
-  deltas/ReduceFunctions.cpp
-  deltas/ReduceGlobalVars.cpp
-  deltas/ReduceMetadata.cpp
   deltas/ReduceArguments.cpp
+  deltas/ReduceAttributes.cpp
   deltas/ReduceBasicBlocks.cpp
+  deltas/ReduceFunctions.cpp
+  deltas/ReduceGlobalVars.cpp
   deltas/ReduceInstructions.cpp
+  deltas/ReduceMetadata.cpp
 
   DEPENDS
   intrinsics_gen

diff --git a/llvm/tools/llvm-reduce/DeltaManager.h b/llvm/tools/llvm-reduce/DeltaManager.h
index 2309c3a..595f130 100644 (file)
--- a/llvm/tools/llvm-reduce/DeltaManager.h
+++ b/llvm/tools/llvm-reduce/DeltaManager.h
@@ -14,11 +14,12 @@
 #include "TestRunner.h"
 #include "deltas/Delta.h"
 #include "deltas/ReduceArguments.h"
+#include "deltas/ReduceAttributes.h"
 #include "deltas/ReduceBasicBlocks.h"
 #include "deltas/ReduceFunctions.h"
 #include "deltas/ReduceGlobalVars.h"
-#include "deltas/ReduceMetadata.h"
 #include "deltas/ReduceInstructions.h"
+#include "deltas/ReduceMetadata.h"
 
 namespace llvm {
 
@@ -30,6 +31,7 @@ inline void runDeltaPasses(TestRunner &Tester) {
   reduceMetadataDeltaPass(Tester);
   reduceArgumentsDeltaPass(Tester);
   reduceInstructionsDeltaPass(Tester);
+  reduceAttributesDeltaPass(Tester);
   // TODO: Implement the remaining Delta Passes
 }
 

diff --git a/llvm/tools/llvm-reduce/deltas/ReduceAttributes.cpp b/llvm/tools/llvm-reduce/deltas/ReduceAttributes.cpp
new file mode 100644 (file)
index 0000000..ac8e0be
--- /dev/null
+++ b/llvm/tools/llvm-reduce/deltas/ReduceAttributes.cpp
@@ -0,0 +1,61 @@
+//===- ReduceAttributes.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 Attributes in the provided Module.
+//
+//===----------------------------------------------------------------------===//
+
+#include "ReduceAttributes.h"
+
+#include "Delta.h"
+#include "TestRunner.h"
+
+#include "llvm/IR/Attributes.h"
+#include "llvm/IR/Function.h"
+#include "llvm/IR/Module.h"
+
+#include <vector>
+
+static void removeAttr(llvm::Function &F, const llvm::Attribute &A) {
+  if (A.isStringAttribute())
+    F.removeFnAttr(A.getKindAsString());
+  else
+    F.removeFnAttr(A.getKindAsEnum());
+}
+
+static void extractAttributes(const std::vector<llvm::Chunk> &ChunksToKeep,
+                              llvm::Module *M) {
+  int AttributeIndex = 0;
+  unsigned ChunkIndex = 0;
+  // TODO: global variables may also have attributes.
+  for (llvm::Function &F : M->getFunctionList()) {
+    for (const llvm::Attribute &A : F.getAttributes().getFnAttributes()) {
+      ++AttributeIndex;
+      if (!ChunksToKeep[ChunkIndex].contains(AttributeIndex))
+        removeAttr(F, A);
+      if (AttributeIndex == ChunksToKeep[ChunkIndex].end)
+        ++ChunkIndex;
+    }
+  }
+}
+
+static int countAttributes(llvm::Module *M) {
+  int TotalAttributeCount = 0;
+  for (const llvm::Function &F : M->getFunctionList())
+    TotalAttributeCount +=
+        F.getAttributes().getFnAttributes().getNumAttributes();
+  // TODO: global variables may also have attributes.
+  return TotalAttributeCount;
+}
+
+void llvm::reduceAttributesDeltaPass(TestRunner &Test) {
+  outs() << "*** Reducing Attributes...\n";
+  int AttributeCount = countAttributes(Test.getProgram());
+  runDeltaPass(Test, AttributeCount, extractAttributes);
+}

diff --git a/llvm/tools/llvm-reduce/deltas/ReduceAttributes.h b/llvm/tools/llvm-reduce/deltas/ReduceAttributes.h
new file mode 100644 (file)
index 0000000..1a20a2b
--- /dev/null
+++ b/llvm/tools/llvm-reduce/deltas/ReduceAttributes.h
@@ -0,0 +1,18 @@
+//===- ReduceAttributes.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 Attributes in the provided Module.
+//
+//===----------------------------------------------------------------------===//
+
+#include "TestRunner.h"
+
+namespace llvm {
+void reduceAttributesDeltaPass(TestRunner &Test);
+} // namespace llvm

diff --git a/llvm/tools/llvm-reduce/deltas/ReduceInstructions.cpp b/llvm/tools/llvm-reduce/deltas/ReduceInstructions.cpp
index b3497ad..6fe10dc 100644 (file)
--- a/llvm/tools/llvm-reduce/deltas/ReduceInstructions.cpp
+++ b/llvm/tools/llvm-reduce/deltas/ReduceInstructions.cpp
@@ -59,7 +59,7 @@ static unsigned countInstructions(Module *Program) {
 }
 
 void llvm::reduceInstructionsDeltaPass(TestRunner &Test) {
-  outs() << "*** Reducing Insructions...\n";
+  outs() << "*** Reducing Instructions...\n";
   unsigned InstCount = countInstructions(Test.getProgram());
   runDeltaPass(Test, InstCount, extractInstrFromModule);
 }