llvm-reduce: Add ReduceDebugInfo pass

[MatzeB]

Summary

Add a ReduceDebugInfo pass. For now this only reduces the lists attached to DICompileUnit metadata: enum types, retained types, global variables and imported entities.

[MatzeB]

Just noticed D135237 at a first glance this may make this pass obsolete...

[MatzeB]

Abandoning in favor of D135237.

llvm/test/tools/llvm-reduce/reduce-debug-info.ll

+; RUN: llvm-reduce --delta-passes=debug-info --test FileCheck --test-arg --check-prefixes=CHECK-INTERESTING --test-arg %s --test-arg --input-file %s -o %t
+; RUN: cat %t | FileCheck %s
+
+; CHECK-INTERESTING-DAG: g_keepme
+; CHECK-INTERESTING-DAG: E_keepme
+; CHECK-INTERESTING-DAG: g_e_keepme
+; CHECK-INTERESTING-DAG: A_keepme
+
+; CHECK: distinct !DICompileUnit(language: DW_LANG_C_plus_plus_14, file: {{![0-9]+}}, isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: [[ENUMS:![0-9]+]], globals: [[GLOBALS:![0-9]+]], splitDebugInlining: false, nameTableKind: None)
+; CHECK: [[ENUMS]] = !{[[ENUM:![0-9]+]]}
+; CHECK: [[ENUM]] = distinct !DICompositeType({{.*}}name: "E_keepme"
+; CHECK: [[GLOBALS]] = !{[[GLOBAL0:![0-9]+]], [[GLOBAL1:![0-9]+]]}
+; CHECK: [[GLOBAL0]] = !DIGlobalVariableExpression(var: [[GLOBAL0VAR:![0-9]+]]
+; CHECK: [[GLOBAL0VAR]] = distinct !DIGlobalVariable(name: "g_keepme"
+; CHECK: [[GLOBAL1]] = !DIGlobalVariableExpression(var: [[GLOBAL1VAR:![0-9]+]]
+; CHECK: [[GLOBAL1VAR]] = distinct !DIGlobalVariable(name: "g_e_keepme"
+
+target triple = "x86_64---"
+
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!23, !24}
+
+!0 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus_14, file: !1, isOptimized: true, runtimeVersion: 0, emissionKind: FullDebug, enums: !2, globals: !10, splitDebugInlining: false, nameTableKind: None)
+!1 = !DIFile(filename: "test.cpp", directory: "/")
+!2 = !{!3, !7}
+!3 = distinct !DICompositeType(tag: DW_TAG_enumeration_type, name: "E_keepme", file: !1, line: 15, baseType: !4, size: 32, elements: !5, identifier: "_ZTS8E_kee
+pme")
+!4 = !DIBasicType(name: "unsigned int", size: 32, encoding: DW_ATE_unsigned)
+!5 = !{!6}
+!6 = !DIEnumerator(name: "E_FOO", value: 5, isUnsigned: true)
+!7 = distinct !DICompositeType(tag: DW_TAG_enumeration_type, name: "E_dropme", file: !1, line: 19, baseType: !4, size: 32, elements: !8, identifier: "_ZTS8E_dropme")
+!8 = !{!9}
+!9 = !DIEnumerator(name: "E_BAM", value: 13, isUnsigned: true)
+!10 = !{!11, !15, !19, !21}
+!11 = !DIGlobalVariableExpression(var: !12, expr: !DIExpression())
+!12 = distinct !DIGlobalVariable(name: "g_keepme", scope: !0, file: !1, line: 12, type: !13, isLocal: false, isDefinition: true)
+!13 = !DIDerivedType(tag: DW_TAG_typedef, name: "A_keepme", file: !1, line: 9, baseType: !14)
+!14 = !DIBasicType(name: "short", size: 16, encoding: DW_ATE_signed)
+!15 = !DIGlobalVariableExpression(var: !16, expr: !DIExpression())
+!16 = distinct !DIGlobalVariable(name: "g_dropme", scope: !0, file: !1, line: 13, type: !17, isLocal: false, isDefinition: true)
+!17 = !DIDerivedType(tag: DW_TAG_typedef, name: "A_dropme", file: !1, line: 10, baseType: !18)
+!18 = !DIBasicType(name: "long long", size: 64, encoding: DW_ATE_signed)
+!19 = !DIGlobalVariableExpression(var: !20, expr: !DIExpression())
+!20 = distinct !DIGlobalVariable(name: "g_e_keepme", scope: !0, file: !1, line: 23, type: !4, isLocal: false, isDefinition: true)
+!21 = !DIGlobalVariableExpression(var: !22, expr: !DIExpression())
+!22 = distinct !DIGlobalVariable(name: "g_e_dropme", scope: !0, file: !1, line: 24, type: !7, isLocal: false, isDefinition: true)
+!23 = !{i32 7, !"Dwarf Version", i32 5}
+!24 = !{i32 2, !"Debug Info Version", i32 3}

llvm/tools/llvm-reduce/CMakeLists.txt

add_llvm_tool(llvm-reduce
   ReducerWorkItem.cpp
   TestRunner.cpp
   deltas/Delta.cpp
   deltas/Utils.cpp
   deltas/ReduceAliases.cpp
   deltas/ReduceArguments.cpp
   deltas/ReduceAttributes.cpp
   deltas/ReduceBasicBlocks.cpp
+  deltas/ReduceDebugInfo.cpp
   deltas/ReduceFunctionBodies.cpp
   deltas/ReduceFunctions.cpp
   deltas/ReduceGlobalObjects.cpp
   deltas/ReduceGlobalValues.cpp
   deltas/ReduceGlobalVarInitializers.cpp
   deltas/ReduceGlobalVars.cpp
   deltas/ReduceInstructions.cpp
   deltas/ReduceMetadata.cpp

llvm/tools/llvm-reduce/DeltaManager.cpp

 #include "DeltaManager.h"
 #include "ReducerWorkItem.h"
 #include "TestRunner.h"
 #include "deltas/Delta.h"
 #include "deltas/ReduceAliases.h"
 #include "deltas/ReduceArguments.h"
 #include "deltas/ReduceAttributes.h"
 #include "deltas/ReduceBasicBlocks.h"
+#include "deltas/ReduceDebugInfo.h"
 #include "deltas/ReduceFunctionBodies.h"
 #include "deltas/ReduceFunctions.h"
 #include "deltas/ReduceGlobalObjects.h"
 #include "deltas/ReduceGlobalValues.h"
 #include "deltas/ReduceGlobalVarInitializers.h"
 #include "deltas/ReduceGlobalVars.h"
 #include "deltas/ReduceIRReferences.h"
 #include "deltas/ReduceInstructionFlagsMIR.h"
do {                                                                         \
     DELTA_PASS("special-globals", reduceSpecialGlobalsDeltaPass)               \
     DELTA_PASS("aliases", reduceAliasesDeltaPass)                              \
     DELTA_PASS("basic-blocks", reduceBasicBlocksDeltaPass)                     \
     DELTA_PASS("global-values", reduceGlobalValuesDeltaPass)                   \
     DELTA_PASS("global-objects", reduceGlobalObjectsDeltaPass)                 \
     DELTA_PASS("global-initializers", reduceGlobalsInitializersDeltaPass)      \
     DELTA_PASS("global-variables", reduceGlobalsDeltaPass)                     \
     DELTA_PASS("metadata", reduceMetadataDeltaPass)                            \
+    DELTA_PASS("debug-info", reduceDebugInfoDeltaPass)                         \
     DELTA_PASS("arguments", reduceArgumentsDeltaPass)                          \
     DELTA_PASS("instructions", reduceInstructionsDeltaPass)                    \
     DELTA_PASS("simplify-instructions", simplifyInstructionsDeltaPass)         \
     DELTA_PASS("ir-passes", runIRPassesDeltaPass)                              \
     DELTA_PASS("operands-zero", reduceOperandsZeroDeltaPass)                   \
     DELTA_PASS("operands-one", reduceOperandsOneDeltaPass)                     \
     DELTA_PASS("operands-nan", reduceOperandsNaNDeltaPass)                     \
     DELTA_PASS("operands-to-args", reduceOperandsToArgsDeltaPass)              \

llvm/tools/llvm-reduce/deltas/ReduceDebugInfo.h

+#ifndef LLVM_TOOLS_LLVM_REDUCE_DELTAS_REDUCEDEBUGINFO_H
+#define LLVM_TOOLS_LLVM_REDUCE_DELTAS_REDUCEDEBUGINFO_H
+
+namespace llvm {
+
+class TestRunner;
+
+void reduceDebugInfoDeltaPass(TestRunner &Test);
+
+} // namespace llvm
+
+#endif

llvm/tools/llvm-reduce/deltas/ReduceDebugInfo.cpp

+#include "ReduceDebugInfo.h"
+
+#include "Delta.h"
+#include "Utils.h"
+#include "llvm/IR/DebugInfo.h"
+#include "llvm/IR/DebugInfoMetadata.h"
+
+namespace llvm {
+
+static MDTuple *reduceTuple(Oracle &O, MDTuple *T) {
+  if (T == nullptr || T->getNumOperands() == 0)
+    return nullptr;
+
+  std::vector<Metadata *> NewEntries;
+  for (const MDOperand &MDO : T->operands()) {
+    if (O.shouldKeep())
+      NewEntries.push_back(MDO.get());
+  }
+  if (NewEntries.size() == T->getNumOperands())
+    return nullptr;
+
+  return MDTuple::get(T->getContext(), NewEntries);
+}
+
+static void reduceCompileUnit(Oracle &O, DICompileUnit &CU) {
+  if (MDTuple *EnumTypes = reduceTuple(O, CU.getEnumTypes().get()))
+    CU.replaceEnumTypes(EnumTypes);
+  if (MDTuple *RetainedTypes = reduceTuple(O, CU.getRetainedTypes().get()))
+    CU.replaceRetainedTypes(RetainedTypes);
+  if (MDTuple *GlobalVariables = reduceTuple(O, CU.getGlobalVariables().get()))
+    CU.replaceGlobalVariables(GlobalVariables);
+  if (MDTuple *ImportedEntities =
+          reduceTuple(O, CU.getImportedEntities().get()))
+    CU.replaceImportedEntities(ImportedEntities);
+}
+
+static void removeDebugInfoFromModule(Oracle &O, Module &M) {
+  for (DICompileUnit *CU : M.debug_compile_units()) {
+    reduceCompileUnit(O, *CU);
+  }
+}
+
+void reduceDebugInfoDeltaPass(TestRunner &Test) {
+  outs() << "*** Reducing DebugInfo...\n";
+  runDeltaPass(Test, removeDebugInfoFromModule);
+  outs() << "----------------------------\n";
+}
+
+} // namespace llvm