From 2e5d20bd478868c80aa595e969d17734690f9b4d Mon Sep 17 00:00:00 2001
From: Kristina Bessonova <kbessonova@accesssoftek.com>
Date: Sun, 19 Jan 2020 16:28:35 +0200
Subject: [PATCH] [llvm-dwarfdump][Statistics] Ignore declarations of global
 variables

Reviewed by: djtodoro

Differential Revision: https://reviews.llvm.org/D73001
---
 llvm/test/tools/llvm-dwarfdump/X86/statistics.ll | 17 +++++++++++++++--
 llvm/tools/llvm-dwarfdump/Statistics.cpp         | 18 +++++++++++-------
 2 files changed, 26 insertions(+), 9 deletions(-)

diff --git a/llvm/test/tools/llvm-dwarfdump/X86/statistics.ll b/llvm/test/tools/llvm-dwarfdump/X86/statistics.ll
index 4e2e111..4fa7f93 100644
--- a/llvm/test/tools/llvm-dwarfdump/X86/statistics.ll
+++ b/llvm/test/tools/llvm-dwarfdump/X86/statistics.ll
@@ -2,6 +2,11 @@
 ; RUN:   | llvm-dwarfdump -statistics - | FileCheck %s
 ; CHECK: "version":4
 
+; namespace test {
+;  extern int a;
+; }
+; using test::a;
+;
 ; int GlobalConst = 42;
 ; int Global;
 ;
@@ -19,9 +24,13 @@
 ; Following variables/arguments/members should be counted:
 ;     - GlobalConst,
 ;     - Global,
-;     - s, s.constant ('fn' and its arguments should be skipped),
+;     - s, s.constant,
 ;     - square::i,
 ;     - cube::i, cube::squared
+; Skipped entities:
+;     - declaration of test::a,
+;     - non-constant member S:fn,
+;     - arguments of S:fn.
 
 ; CHECK: "unique source variables":7
 ; +1 extra inline i.
@@ -100,7 +109,7 @@ attributes #2 = { noinline nounwind optnone ssp uwtable }
 
 !0 = !DIGlobalVariableExpression(var: !1, expr: !DIExpression())
 !1 = distinct !DIGlobalVariable(name: "GlobalConst", scope: !2, file: !3, line: 1, type: !8, isLocal: false, isDefinition: true)
-!2 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !3, producer: "clang version 6.0.0 (trunk 310529) (llvm/trunk 310534)", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !4, globals: !5)
+!2 = distinct !DICompileUnit(language: DW_LANG_C_plus_plus, file: !3, producer: "clang version 6.0.0 (trunk 310529) (llvm/trunk 310534)", isOptimized: false, runtimeVersion: 0, emissionKind: FullDebug, enums: !4, imports: !48, globals: !5)
 !3 = !DIFile(filename: "/tmp/quality.cpp", directory: "/Volumes/Data/llvm")
 !4 = !{}
 !5 = !{!0, !6, !9}
@@ -146,3 +155,7 @@ attributes #2 = { noinline nounwind optnone ssp uwtable }
 !45 = !DIDerivedType(tag: DW_TAG_member, name: "fn", scope: !11, file: !3, line: 5, baseType: !46, size: 64)
 !46 = !DIDerivedType(tag: DW_TAG_pointer_type, baseType: !47, size: 64)
 !47 = !DISubroutineType(types: !22)
+!48 = !{!49}
+!49 = !DIImportedEntity(tag: DW_TAG_imported_declaration, scope: !2, entity: !50, file: !3, line: 2)
+!50 = !DIGlobalVariable(name: "a", linkageName: "_ZN4test1aE", scope: !51, file: !3, line: 2, type: !8, isLocal: false, isDefinition: false)
+!51 = !DINamespace(name: "test", scope: !2)
diff --git a/llvm/tools/llvm-dwarfdump/Statistics.cpp b/llvm/tools/llvm-dwarfdump/Statistics.cpp
index 642484f..6bc1b0e 100644
--- a/llvm/tools/llvm-dwarfdump/Statistics.cpp
+++ b/llvm/tools/llvm-dwarfdump/Statistics.cpp
@@ -202,7 +202,7 @@ static void collectStatsForDie(DWARFDie Die, std::string FnPrefix,
   uint64_t BytesEntryValuesCovered = 0;
   auto &FnStats = FnStatMap[FnPrefix];
   bool IsParam = Die.getTag() == dwarf::DW_TAG_formal_parameter;
-  bool IsLocalVar = Die.getTag() == dwarf::DW_TAG_variable;
+  bool IsVariable = Die.getTag() == dwarf::DW_TAG_variable;
 
   if (Die.getTag() == dwarf::DW_TAG_call_site ||
       Die.getTag() == dwarf::DW_TAG_GNU_call_site) {
@@ -216,11 +216,15 @@ static void collectStatsForDie(DWARFDie Die, std::string FnPrefix,
     return;
   }
 
-  if (!IsParam && !IsLocalVar && Die.getTag() != dwarf::DW_TAG_member) {
+  if (!IsParam && !IsVariable && Die.getTag() != dwarf::DW_TAG_member) {
     // Not a variable or constant member.
     return;
   }
 
+  // Ignore declarations of global variables.
+  if (IsVariable && Die.find(dwarf::DW_AT_declaration))
+    return;
+
   if (Die.findRecursively(dwarf::DW_AT_decl_file) &&
       Die.findRecursively(dwarf::DW_AT_decl_line))
     HasSrcLoc = true;
@@ -282,17 +286,17 @@ static void collectStatsForDie(DWARFDie Die, std::string FnPrefix,
     LocStats.NumVarParam++;
     if (IsParam)
       LocStats.NumParam++;
-    else if (IsLocalVar)
+    else if (IsVariable)
       LocStats.NumVar++;
 
     collectLocStats(BytesCovered, BytesInScope, LocStats.VarParamLocStats,
                     LocStats.ParamLocStats, LocStats.VarLocStats, IsParam,
-                    IsLocalVar);
+                    IsVariable);
     // Non debug entry values coverage statistics.
     collectLocStats(BytesCovered - BytesEntryValuesCovered, BytesInScope,
                     LocStats.VarParamNonEntryValLocStats,
                     LocStats.ParamNonEntryValLocStats,
-                    LocStats.VarNonEntryValLocStats, IsParam, IsLocalVar);
+                    LocStats.VarNonEntryValLocStats, IsParam, IsVariable);
   }
 
   // Collect PC range coverage data.
@@ -314,7 +318,7 @@ static void collectStatsForDie(DWARFDie Die, std::string FnPrefix,
           std::min(BytesInScope, BytesCovered);
       GlobalStats.ParamScopeBytes += BytesInScope;
       GlobalStats.ParamScopeEntryValueBytesCovered += BytesEntryValuesCovered;
-    } else if (IsLocalVar) {
+    } else if (IsVariable) {
       GlobalStats.VarScopeBytesCovered += std::min(BytesInScope, BytesCovered);
       GlobalStats.VarScopeBytes += BytesInScope;
       GlobalStats.VarScopeEntryValueBytesCovered += BytesEntryValuesCovered;
@@ -334,7 +338,7 @@ static void collectStatsForDie(DWARFDie Die, std::string FnPrefix,
         FnStats.NumParamSourceLocations++;
       if (HasLoc)
         FnStats.NumParamLocations++;
-    } else if (IsLocalVar) {
+    } else if (IsVariable) {
       FnStats.NumVars++;
       if (HasType)
         FnStats.NumVarTypes++;
-- 
2.7.4