Remove support for versioned debug info.

Versioned debug info support has been a burden to maintain & also compromised
current debug info verification by causing test cases testing old debug info to
remain rather than being updated to the latest. It also makes it hard to add or
change the metadata schema by requiring various backwards-compatibility in the
DI* hierarchy.

So it's being removed in preparation for new changes to the schema to tidy up
old/unnecessary fields and add new fields needed for new debug info (well, new
to LLVM at least).

The more surprising part of this is the changes to DI*::Verify - this became
necessary due to the changes to AsmWriter. AsmWriter was relying on the version
test to decide which bits of metadata were actually debug info when printing
the comment annotations. Without the version information the tag numbers were
too common & it would print debug info on random metadata that happened to
start with an integer that matched a tag number. Instead this change makes the
Verify functions more precise (just adding "number of operands" checks - not
type checking those operands yet) & relies on that to decide which metadata is
debug info metadata.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@176838 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 24 insertions, 108 deletions

diff --git a/lib/CodeGen/AsmPrinter/DwarfDebug.cpp b/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
index bc0e84b0f1..30bfa78989 100644
--- a/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
+++ b/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
@@ -756,82 +756,6 @@ void DwarfDebug::constructSubprogramDIE(CompileUnit *TheCU,
     TheCU->addGlobalName(SP.getName(), SubprogramDie);
 }
 
-// Collect debug info from named mdnodes such as llvm.dbg.enum and llvm.dbg.ty.
-void DwarfDebug::collectInfoFromNamedMDNodes(const Module *M) {
-  if (NamedMDNode *NMD = M->getNamedMetadata("llvm.dbg.sp"))
-    for (unsigned i = 0, e = NMD->getNumOperands(); i != e; ++i) {
-      const MDNode *N = NMD->getOperand(i);
-      if (CompileUnit *CU = CUMap.lookup(DISubprogram(N).getCompileUnit()))
-        constructSubprogramDIE(CU, N);
-    }
-
-  if (NamedMDNode *NMD = M->getNamedMetadata("llvm.dbg.gv"))
-    for (unsigned i = 0, e = NMD->getNumOperands(); i != e; ++i) {
-      const MDNode *N = NMD->getOperand(i);
-      if (CompileUnit *CU = CUMap.lookup(DIGlobalVariable(N).getCompileUnit()))
-        CU->createGlobalVariableDIE(N);
-    }
-
-  if (NamedMDNode *NMD = M->getNamedMetadata("llvm.dbg.enum"))
-    for (unsigned i = 0, e = NMD->getNumOperands(); i != e; ++i) {
-      DIType Ty(NMD->getOperand(i));
-      if (CompileUnit *CU = CUMap.lookup(Ty.getCompileUnit()))
-        CU->getOrCreateTypeDIE(Ty);
-    }
-
-  if (NamedMDNode *NMD = M->getNamedMetadata("llvm.dbg.ty"))
-    for (unsigned i = 0, e = NMD->getNumOperands(); i != e; ++i) {
-      DIType Ty(NMD->getOperand(i));
-      if (CompileUnit *CU = CUMap.lookup(Ty.getCompileUnit()))
-        CU->getOrCreateTypeDIE(Ty);
-    }
-}
-
-// Collect debug info using DebugInfoFinder.
-// FIXME - Remove this when dragonegg switches to DIBuilder.
-bool DwarfDebug::collectLegacyDebugInfo(const Module *M) {
-  DebugInfoFinder DbgFinder;
-  DbgFinder.processModule(*M);
-
-  bool HasDebugInfo = false;
-  // Scan all the compile-units to see if there are any marked as the main
-  // unit. If not, we do not generate debug info.
-  for (DebugInfoFinder::iterator I = DbgFinder.compile_unit_begin(),
-         E = DbgFinder.compile_unit_end(); I != E; ++I) {
-    if (DICompileUnit(*I).isMain()) {
-      HasDebugInfo = true;
-      break;
-    }
-  }
-  if (!HasDebugInfo) return false;
-
-  // Emit initial sections so we can refer to them later.
-  emitSectionLabels();
-
-  // Create all the compile unit DIEs.
-  for (DebugInfoFinder::iterator I = DbgFinder.compile_unit_begin(),
-         E = DbgFinder.compile_unit_end(); I != E; ++I)
-    constructCompileUnit(*I);
-
-  // Create DIEs for each global variable.
-  for (DebugInfoFinder::iterator I = DbgFinder.global_variable_begin(),
-         E = DbgFinder.global_variable_end(); I != E; ++I) {
-    const MDNode *N = *I;
-    if (CompileUnit *CU = CUMap.lookup(DIGlobalVariable(N).getCompileUnit()))
-      CU->createGlobalVariableDIE(N);
-  }
-
-  // Create DIEs for each subprogram.
-  for (DebugInfoFinder::iterator I = DbgFinder.subprogram_begin(),
-         E = DbgFinder.subprogram_end(); I != E; ++I) {
-    const MDNode *N = *I;
-    if (CompileUnit *CU = CUMap.lookup(DISubprogram(N).getCompileUnit()))
-      constructSubprogramDIE(CU, N);
-  }
-
-  return HasDebugInfo;
-}
-
 // Emit all Dwarf sections that should come prior to the content. Create
 // global DIEs and emit initial debug info sections. This is invoked by
 // the target AsmPrinter.
@@ -844,30 +768,28 @@ void DwarfDebug::beginModule() {
   // If module has named metadata anchors then use them, otherwise scan the
   // module using debug info finder to collect debug info.
   NamedMDNode *CU_Nodes = M->getNamedMetadata("llvm.dbg.cu");
-  if (CU_Nodes) {
-    // Emit initial sections so we can reference labels later.
-    emitSectionLabels();
-
-    for (unsigned i = 0, e = CU_Nodes->getNumOperands(); i != e; ++i) {
-      DICompileUnit CUNode(CU_Nodes->getOperand(i));
-      CompileUnit *CU = constructCompileUnit(CUNode);
-      DIArray GVs = CUNode.getGlobalVariables();
-      for (unsigned i = 0, e = GVs.getNumElements(); i != e; ++i)
-        CU->createGlobalVariableDIE(GVs.getElement(i));
-      DIArray SPs = CUNode.getSubprograms();
-      for (unsigned i = 0, e = SPs.getNumElements(); i != e; ++i)
-        constructSubprogramDIE(CU, SPs.getElement(i));
-      DIArray EnumTypes = CUNode.getEnumTypes();
-      for (unsigned i = 0, e = EnumTypes.getNumElements(); i != e; ++i)
-        CU->getOrCreateTypeDIE(EnumTypes.getElement(i));
-      DIArray RetainedTypes = CUNode.getRetainedTypes();
-      for (unsigned i = 0, e = RetainedTypes.getNumElements(); i != e; ++i)
-        CU->getOrCreateTypeDIE(RetainedTypes.getElement(i));
-    }
-  } else if (!collectLegacyDebugInfo(M))
+  if (!CU_Nodes)
     return;
 
-  collectInfoFromNamedMDNodes(M);
+  // Emit initial sections so we can reference labels later.
+  emitSectionLabels();
+
+  for (unsigned i = 0, e = CU_Nodes->getNumOperands(); i != e; ++i) {
+    DICompileUnit CUNode(CU_Nodes->getOperand(i));
+    CompileUnit *CU = constructCompileUnit(CUNode);
+    DIArray GVs = CUNode.getGlobalVariables();
+    for (unsigned i = 0, e = GVs.getNumElements(); i != e; ++i)
+      CU->createGlobalVariableDIE(GVs.getElement(i));
+    DIArray SPs = CUNode.getSubprograms();
+    for (unsigned i = 0, e = SPs.getNumElements(); i != e; ++i)
+      constructSubprogramDIE(CU, SPs.getElement(i));
+    DIArray EnumTypes = CUNode.getEnumTypes();
+    for (unsigned i = 0, e = EnumTypes.getNumElements(); i != e; ++i)
+      CU->getOrCreateTypeDIE(EnumTypes.getElement(i));
+    DIArray RetainedTypes = CUNode.getRetainedTypes();
+    for (unsigned i = 0, e = RetainedTypes.getNumElements(); i != e; ++i)
+      CU->getOrCreateTypeDIE(RetainedTypes.getElement(i));
+  }
 
   // Tell MMI that we have debug info.
   MMI->setDebugInfoAvailability(true);
@@ -1211,16 +1133,10 @@ DwarfDebug::collectVariableInfo(const MachineFunction *MF,
     if (DV.getTag() == dwarf::DW_TAG_arg_variable &&
         DISubprogram(DV.getContext()).describes(MF->getFunction()))
       Scope = LScopes.getCurrentFunctionScope();
-    else {
-      if (DV.getVersion() <= LLVMDebugVersion9)
-        Scope = LScopes.findLexicalScope(MInsn->getDebugLoc());
-      else {
-        if (MDNode *IA = DV.getInlinedAt())
-          Scope = LScopes.findInlinedScope(DebugLoc::getFromDILocation(IA));
-        else
-          Scope = LScopes.findLexicalScope(cast<MDNode>(DV->getOperand(1)));
-      }
-    }
+    else if (MDNode *IA = DV.getInlinedAt())
+      Scope = LScopes.findInlinedScope(DebugLoc::getFromDILocation(IA));
+    else
+      Scope = LScopes.findLexicalScope(cast<MDNode>(DV->getOperand(1)));
     // If variable scope is not found then skip this variable.
     if (!Scope)
       continue;