DebugInfo: Create abstract function definitions even when concrete definitions preceed inline definitions.

After much puppetry, here's the major piece of the work to ensure that
even when a concrete definition preceeds all inline definitions, an
abstract definition is still created and referenced from both concrete
and inline definitions.

Variables are still broken in this case (see comment in
dbg-value-inlined-parameter.ll test case) and will be addressed in
follow up work.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@209677 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 35 insertions, 46 deletions

diff --git a/lib/CodeGen/AsmPrinter/DwarfDebug.cpp b/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
index c28c20d68a..c0badde368 100644
--- a/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
+++ b/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
@@ -316,20 +316,6 @@ DIE &DwarfDebug::updateSubprogramScopeDIE(DwarfCompileUnit &SPCU,
                                           DISubprogram SP) {
   DIE *SPDie = SPCU.getOrCreateSubprogramDIE(SP);
 
-  assert(SPDie && "Unable to find subprogram DIE!");
-
-  // If we're updating an abstract DIE, then we will be adding the children and
-  // object pointer later on. But what we don't want to do is process the
-  // concrete DIE twice.
-  if (DIE *AbsSPDIE = AbstractSPDies.lookup(SP)) {
-    assert(SPDie == AbsSPDIE);
-    // Pick up abstract subprogram DIE.
-    SPDie = &SPCU.createAndAddDIE(
-        dwarf::DW_TAG_subprogram,
-        *SPCU.getOrCreateContextDIE(resolve(SP.getContext())));
-    SPCU.addDIEEntry(*SPDie, dwarf::DW_AT_abstract_origin, *AbsSPDIE);
-  }
-
   attachLowHighPC(SPCU, *SPDie, FunctionBeginSym, FunctionEndSym);
 
   const TargetRegisterInfo *RI = Asm->TM.getRegisterInfo();
@@ -525,6 +511,8 @@ void DwarfDebug::constructAbstractSubprogramScopeDIE(DwarfCompileUnit &TheCU,
 
   DISubprogram SP(Scope->getScopeNode());
 
+  ProcessedSPNodes.insert(SP);
+
   DIE *&AbsDef = AbstractSPDies[SP];
   if (AbsDef)
     return;
@@ -532,10 +520,24 @@ void DwarfDebug::constructAbstractSubprogramScopeDIE(DwarfCompileUnit &TheCU,
   // Find the subprogram's DwarfCompileUnit in the SPMap in case the subprogram
   // was inlined from another compile unit.
   DwarfCompileUnit &SPCU = *SPMap[SP];
-  AbsDef = SPCU.getOrCreateSubprogramDIE(SP);
+  DIE *ContextDIE;
+
+  // Some of this is duplicated from DwarfUnit::getOrCreateSubprogramDIE, with
+  // the important distinction that the DIDescriptor is not associated with the
+  // DIE (since the DIDescriptor will be associated with the concrete DIE, if
+  // any). It could be refactored to some common utility function.
+  if (DISubprogram SPDecl = SP.getFunctionDeclaration()) {
+    ContextDIE = &SPCU.getUnitDie();
+    SPCU.getOrCreateSubprogramDIE(SPDecl);
+  } else
+    ContextDIE = SPCU.getOrCreateContextDIE(resolve(SP.getContext()));
 
-  if (!ProcessedSPNodes.insert(SP))
-    return;
+  // Passing null as the associated DIDescriptor because the abstract definition
+  // shouldn't be found by lookup.
+  AbsDef = &SPCU.createAndAddDIE(dwarf::DW_TAG_subprogram, *ContextDIE,
+                                 DIDescriptor());
+  SPCU.applySubprogramAttributes(SP, *AbsDef);
+  SPCU.addGlobalName(SP.getName(), *AbsDef, resolve(SP.getContext()));
 
   SPCU.addUInt(*AbsDef, dwarf::DW_AT_inline, None, dwarf::DW_INL_inlined);
   createAndAddScopeChildren(SPCU, Scope, *AbsDef);
@@ -686,28 +688,6 @@ DwarfCompileUnit &DwarfDebug::constructDwarfCompileUnit(DICompileUnit DIUnit) {
   return NewCU;
 }
 
-// Construct subprogram DIE.
-void DwarfDebug::constructSubprogramDIE(DwarfCompileUnit &TheCU,
-                                        const MDNode *N) {
-  // FIXME: We should only call this routine once, however, during LTO if a
-  // program is defined in multiple CUs we could end up calling it out of
-  // beginModule as we walk the CUs.
-
-  DwarfCompileUnit *&CURef = SPMap[N];
-  if (CURef)
-    return;
-  CURef = &TheCU;
-
-  DISubprogram SP(N);
-  assert(SP.isSubprogram());
-  assert(SP.isDefinition());
-
-  DIE &SubprogramDie = *TheCU.getOrCreateSubprogramDIE(SP);
-
-  // Expose as a global name.
-  TheCU.addGlobalName(SP.getName(), SubprogramDie, resolve(SP.getContext()));
-}
-
 void DwarfDebug::constructImportedEntityDIE(DwarfCompileUnit &TheCU,
                                             const MDNode *N) {
   DIImportedEntity Module(N);
@@ -826,12 +806,19 @@ void DwarfDebug::finishSubprogramDefinitions() {
       if (SPMap[SP] != SPCU)
         continue;
       DIE *D = SPCU->getDIE(SP);
-      if (!D)
-        // Lazily construct the subprogram if we didn't see either concrete or
-        // inlined versions during codegen.
-        D = SPCU->getOrCreateSubprogramDIE(SP);
-      SPCU->applySubprogramAttributes(SP, *D);
-      SPCU->addGlobalName(SP.getName(), *D, resolve(SP.getContext()));
+      if (DIE *AbsSPDIE = AbstractSPDies.lookup(SP)) {
+        if (D)
+          // If this subprogram has an abstract definition, reference that
+          SPCU->addDIEEntry(*D, dwarf::DW_AT_abstract_origin, *AbsSPDIE);
+      } else {
+        if (!D)
+          // Lazily construct the subprogram if we didn't see either concrete or
+          // inlined versions during codegen.
+          D = SPCU->getOrCreateSubprogramDIE(SP);
+        // And attach the attributes
+        SPCU->applySubprogramAttributes(SP, *D);
+        SPCU->addGlobalName(SP.getName(), *D, resolve(SP.getContext()));
+      }
     }
   }
 }
@@ -861,7 +848,9 @@ void DwarfDebug::collectDeadVariables() {
         if (Variables.getNumElements() == 0)
           continue;
 
-        DIE *SPDIE = SPCU->getDIE(SP);
+        DIE *SPDIE = AbstractSPDies.lookup(SP);
+        if (!SPDIE)
+          SPDIE = SPCU->getDIE(SP);
         assert(SPDIE);
         for (unsigned vi = 0, ve = Variables.getNumElements(); vi != ve; ++vi) {
           DIVariable DV(Variables.getElement(vi));