7 files changed, 24 insertions, 76 deletions
diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp b/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
index a51342a7fee..0daca72b30d 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp
@@ -695,25 +695,6 @@ void DwarfCompileUnit::finishSubprogramDefinition(const DISubprogram *SP) {
       applySubprogramAttributesToDefinition(SP, *D);
   }
 }
-void DwarfCompileUnit::collectDeadVariables(const DISubprogram *SP) {
-  assert(SP && "CU's subprogram list contains a non-subprogram");
-  assert(SP->isDefinition() &&
-         "CU's subprogram list contains a subprogram declaration");
-  auto Variables = SP->getVariables();
-  if (Variables.size() == 0)
-    return;
-
-  DIE *SPDIE = DU->getAbstractSPDies().lookup(SP);
-  if (!SPDIE)
-    SPDIE = getDIE(SP);
-  assert(SPDIE);
-  for (const DILocalVariable *DV : Variables) {
-    DbgVariable NewVar(DV, /* IA */ nullptr, DD);
-    auto VariableDie = constructVariableDIE(NewVar);
-    applyVariableAttributes(NewVar, *VariableDie);
-    SPDIE->addChild(std::move(VariableDie));
-  }
-}
 
 void DwarfCompileUnit::emitHeader(bool UseOffsets) {
   // Don't bother labeling the .dwo unit, as its offset isn't used.
diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.h b/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.h
index bacf87d95c4..1170b379080 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.h
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.h
@@ -180,8 +180,6 @@ public:
 
   void finishSubprogramDefinition(const DISubprogram *SP);
 
-  void collectDeadVariables(const DISubprogram *SP);
-
   /// Set the skeleton unit associated with this unit.
   void setSkeleton(DwarfCompileUnit &Skel) { Skeleton = &Skel; }
 
diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp b/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
index d9d265ef2b9..9195ca310a2 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
@@ -526,32 +526,10 @@ void DwarfDebug::finishVariableDefinitions() {
 
 void DwarfDebug::finishSubprogramDefinitions() {
   for (const auto &P : SPMap)
-    forBothCUs(*P.second, [&](DwarfCompileUnit &CU) {
-      CU.finishSubprogramDefinition(cast<DISubprogram>(P.first));
-    });
-}
-
-// Collect info for variables that were optimized out.
-void DwarfDebug::collectDeadVariables() {
-  const Module *M = MMI->getModule();
-
-  if (NamedMDNode *CU_Nodes = M->getNamedMetadata("llvm.dbg.cu")) {
-    for (MDNode *N : CU_Nodes->operands()) {
-      auto *TheCU = cast<DICompileUnit>(N);
-      if (TheCU->getEmissionKind() == DICompileUnit::NoDebug)
-        continue;
-
-      // Construct subprogram DIE and add variables DIEs.
-      DwarfCompileUnit *SPCU =
-          static_cast<DwarfCompileUnit *>(CUMap.lookup(TheCU));
-      assert(SPCU && "Unable to find Compile Unit!");
-      for (auto *SP : TheCU->getSubprograms()) {
-        if (ProcessedSPNodes.count(SP) != 0)
-          continue;
-        SPCU->collectDeadVariables(SP);
-      }
-    }
-  }
+    if (ProcessedSPNodes.count(P.first))
+      forBothCUs(*P.second, [&](DwarfCompileUnit &CU) {
+          CU.finishSubprogramDefinition(cast<DISubprogram>(P.first));
+        });
 }
 
 void DwarfDebug::finalizeModuleInfo() {
@@ -561,9 +539,6 @@ void DwarfDebug::finalizeModuleInfo() {
 
   finishVariableDefinitions();
 
-  // Collect info for variables that were optimized out.
-  collectDeadVariables();
-
   // Handle anything that needs to be done on a per-unit basis after
   // all other generation.
   for (const auto &P : CUMap) {
@@ -1129,6 +1104,10 @@ void DwarfDebug::endFunction(const MachineFunction *MF) {
     PrevCU = nullptr;
     CurFn = nullptr;
     DebugHandlerBase::endFunction(MF);
+    // Mark functions with no debug info on any instructions, but a
+    // valid DISubprogram as processed.
+    if (auto *SP = MF->getFunction()->getSubprogram())
+      ProcessedSPNodes.insert(SP);
     return;
   }
 
diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.h b/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.h
index f0859ec1a8f..1f83434c530 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.h
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.h
@@ -320,9 +320,6 @@ class DwarfDebug : public DebugHandlerBase {
   /// Construct a DIE for this abstract scope.
   void constructAbstractSubprogramScopeDIE(LexicalScope *Scope);
 
-  /// Collect info for variables that were optimized out.
-  void collectDeadVariables();
-
   void finishVariableDefinitions();
 
   void finishSubprogramDefinitions();
diff --git a/llvm/test/DebugInfo/Generic/cross-cu-linkonce-distinct.ll b/llvm/test/DebugInfo/Generic/cross-cu-linkonce-distinct.ll
index b649ba662b1..875c39862dc 100644
--- a/llvm/test/DebugInfo/Generic/cross-cu-linkonce-distinct.ll
+++ b/llvm/test/DebugInfo/Generic/cross-cu-linkonce-distinct.ll
@@ -26,24 +26,16 @@
 ; }
 ; int (*y)(int) = &func;
 
+; The DISubprogram should show up in compile unit a.
 ; CHECK: DW_TAG_compile_unit
-; CHECK:   DW_TAG_subprogram
 ; CHECK-NOT: DW_TAG
-; CHECK:     DW_AT_name {{.*}} "func"
-; CHECK: DW_TAG_compile_unit
-
-; FIXME: Maybe we should drop the subprogram here - since the function was
-; emitted in one CU, due to linkonce_odr uniquing. We certainly don't emit the
-; subprogram here if the source location for this definition is the same (see
-; test/DebugInfo/cross-cu-linkonce.ll), though it's very easy to tickle that
-; into failing even without duplicating the source as has been done in this
-; case (two cpp files in different directories, including the same header that
-; contains an inline function - clang will produce distinct subprogram metadata
-; that won't deduplicate owing to the file location information containing the
-; directory of the source file even though the file name is absolute, not
-; relative)
+; CHECK:    DW_AT_name {{.*}}"b.cpp"
+; CHECK-NOT: DW_TAG_subprogram
 
-; CHECK: DW_TAG_subprogram
+; CHECK: DW_TAG_compile_unit
+; CHECK-NOT: DW_TAG
+; CHECK:     DW_AT_name {{.*}}"a.cpp"
+; CHECK:     DW_AT_name {{.*}} "func"
 
 @x = global i32 (i32)* @_Z4funci, align 8
 @y = global i32 (i32)* @_Z4funci, align 8
@@ -61,7 +53,7 @@ define linkonce_odr i32 @_Z4funci(i32 %i) #0 !dbg !4 {
 ; Function Attrs: nounwind readnone
 declare void @llvm.dbg.declare(metadata, metadata, metadata) #1
 
-attributes #0 = { inlinehint nounwind uwtable "less-precise-fpmad"="false" "no-frame-pointer-elim"="true" "no-frame-pointer-elim-non-leaf" "no-infs-fp-math"="false" "no-nans-fp-math"="false" "stack-protector-buffer-size"="8" "unsafe-fp-math"="false" "use-soft-float"="false" }
+attributes #0 = { inlinehint nounwind uwtable }
 attributes #1 = { nounwind readnone }
 
 !llvm.dbg.cu = !{!12, !0}
diff --git a/llvm/test/DebugInfo/Generic/nodebug.ll b/llvm/test/DebugInfo/Generic/nodebug.ll
index 35da65d3b8b..aa7f85a91a6 100644
--- a/llvm/test/DebugInfo/Generic/nodebug.ll
+++ b/llvm/test/DebugInfo/Generic/nodebug.ll
@@ -16,10 +16,8 @@
 ;   f1();
 ; }
 
-; Check that there's only one DW_TAG_subprogram, nothing for the 'f2' function.
-; CHECK: DW_TAG_subprogram
-; CHECK-NOT: DW_TAG
-; CHECK:   DW_AT_name {{.*}} "f1"
+; Check that there's no DW_TAG_subprogram, not even for the 'f2' function.
+; CHECK: DW_TAG_compile_unit
 ; CHECK-NOT: DW_TAG_subprogram
 
 @i = external global i32
diff --git a/llvm/test/DebugInfo/X86/debug-dead-local-var.ll b/llvm/test/DebugInfo/X86/debug-dead-local-var.ll
index 66a45a78dba..fc04f6dc416 100644
--- a/llvm/test/DebugInfo/X86/debug-dead-local-var.ll
+++ b/llvm/test/DebugInfo/X86/debug-dead-local-var.ll
@@ -11,9 +11,12 @@
 ;   return 1;
 ; }
 
-; Check that we still have the structure type for X even though we're not
-; going to emit a low/high_pc for foo.
-; CHECK: DW_TAG_structure_type
+; Check that we don't have the structure type for X since its scope has
+; been optimized away.
+; CHECK-NOT: DW_TAG_structure_type
+; CHECK: DW_TAG_subprogram
+; CHECK: DW_AT_name {{.*}}"bar"
+; CHECK-NOT: DW_TAG_structure_type
 
 ; Function Attrs: nounwind readnone uwtable
 define i32 @bar() #0 !dbg !4 {