2 files changed, 37 insertions, 24 deletions

diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp b/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
index 742646b0555..7cd06931249 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
@@ -856,12 +856,14 @@ void DwarfDebug::finishSubprogramDefinitions() {
           // If this subprogram has an abstract definition, reference that
           SPCU->addDIEEntry(*D, dwarf::DW_AT_abstract_origin, *AbsSPDIE);
       } else {
-        if (!D)
+        if (!D && TheCU.getEmissionKind() != DIBuilder::LineTablesOnly)
           // Lazily construct the subprogram if we didn't see either concrete or
-          // inlined versions during codegen.
+          // inlined versions during codegen. (except in -gmlt ^ where we want
+          // to omit these entirely)
           D = SPCU->getOrCreateSubprogramDIE(SP);
-        // And attach the attributes
-        SPCU->applySubprogramAttributesToDefinition(SP, *D);
+        if (D)
+          // And attach the attributes
+          SPCU->applySubprogramAttributesToDefinition(SP, *D);
       }
     }
   }
@@ -1690,6 +1692,24 @@ void DwarfDebug::endFunction(const MachineFunction *MF) {
   LexicalScope *FnScope = LScopes.getCurrentFunctionScope();
   DwarfCompileUnit &TheCU = *SPMap.lookup(FnScope->getScopeNode());
 
+  // Add the range of this function to the list of ranges for the CU.
+  TheCU.addRange(RangeSpan(FunctionBeginSym, FunctionEndSym));
+
+  // Under -gmlt, skip building the subprogram if there are no inlined
+  // subroutines inside it.
+  if (TheCU.getCUNode().getEmissionKind() == DIBuilder::LineTablesOnly &&
+      LScopes.getAbstractScopesList().empty()) {
+    assert(ScopeVariables.empty());
+    assert(CurrentFnArguments.empty());
+    assert(DbgValues.empty());
+    assert(AbstractVariables.empty());
+    LabelsBeforeInsn.clear();
+    LabelsAfterInsn.clear();
+    PrevLabel = nullptr;
+    CurFn = nullptr;
+    return;
+  }
+
   // Construct abstract scopes.
   for (LexicalScope *AScope : LScopes.getAbstractScopesList()) {
     DISubprogram SP(AScope->getScopeNode());
@@ -1710,10 +1730,6 @@ void DwarfDebug::endFunction(const MachineFunction *MF) {
   if (!CurFn->getTarget().Options.DisableFramePointerElim(*CurFn))
     TheCU.addFlag(CurFnDIE, dwarf::DW_AT_APPLE_omit_frame_ptr);
 
-  // Add the range of this function to the list of ranges for the CU.
-  RangeSpan Span(FunctionBeginSym, FunctionEndSym);
-  TheCU.addRange(std::move(Span));
-
   // Clear debug info
   // Ownership of DbgVariables is a bit subtle - ScopeVariables owns all the
   // DbgVariables except those that are also in AbstractVariables (since they
diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp b/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp
index 4bf18db32ff..b6514e6b5d6 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp
@@ -2049,23 +2049,20 @@ void DwarfUnit::emitHeader(const MCSymbol *ASectionSym) const {
 }
 
 void DwarfCompileUnit::addRange(RangeSpan Range) {
-  // Only add a range for this unit if we're emitting full debug.
-  if (getCUNode().getEmissionKind() == DIBuilder::FullDebug) {
-    bool SameAsPrevCU = this == DD->getPrevCU();
-    DD->setPrevCU(this);
-    // If we have no current ranges just add the range and return, otherwise,
-    // check the current section and CU against the previous section and CU we
-    // emitted into and the subprogram was contained within. If these are the
-    // same then extend our current range, otherwise add this as a new range.
-    if (CURanges.empty() || !SameAsPrevCU ||
-        (&CURanges.back().getEnd()->getSection() !=
-         &Range.getEnd()->getSection())) {
-      CURanges.push_back(Range);
-      return;
-    }
-
-    CURanges.back().setEnd(Range.getEnd());
+  bool SameAsPrevCU = this == DD->getPrevCU();
+  DD->setPrevCU(this);
+  // If we have no current ranges just add the range and return, otherwise,
+  // check the current section and CU against the previous section and CU we
+  // emitted into and the subprogram was contained within. If these are the
+  // same then extend our current range, otherwise add this as a new range.
+  if (CURanges.empty() || !SameAsPrevCU ||
+      (&CURanges.back().getEnd()->getSection() !=
+       &Range.getEnd()->getSection())) {
+    CURanges.push_back(Range);
+    return;
   }
+
+  CURanges.back().setEnd(Range.getEnd());
 }
 
 void DwarfCompileUnit::initStmtList(MCSymbol *DwarfLineSectionSym) {