3 files changed, 41 insertions, 17 deletions

diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp b/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
index 2fe6a2dfb7e..40fe0e9cb49 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
@@ -94,6 +94,11 @@ static cl::opt<bool> GenerateARangeSection("generate-arange-section",
                                            cl::desc("Generate dwarf aranges"),
                                            cl::init(false));
 
+static cl::opt<bool>
+    GenerateDwarfTypeUnits("generate-type-units", cl::Hidden,
+                           cl::desc("Generate DWARF4 type units."),
+                           cl::init(false));
+
 static cl::opt<bool> SplitDwarfCrossCuReferences(
     "split-dwarf-cross-cu-references", cl::Hidden,
     cl::desc("Enable cross-cu references in DWO files"), cl::init(false));
@@ -284,6 +289,29 @@ void DbgVariable::addMMIEntry(const DbgVariable &V) {
          "conflicting locations for variable");
 }
 
+static AccelTableKind computeAccelTableKind(unsigned DwarfVersion,
+                                            bool GenerateTypeUnits,
+                                            DebuggerKind Tuning,
+                                            const Triple &TT) {
+  // Honor an explicit request.
+  if (AccelTables != AccelTableKind::Default)
+    return AccelTables;
+
+  // Accelerator tables with type units are currently not supported.
+  if (GenerateTypeUnits)
+    return AccelTableKind::None;
+
+  // Accelerator tables get emitted if targetting DWARF v5 or LLDB.  DWARF v5
+  // always implies debug_names. For lower standard versions we use apple
+  // accelerator tables on apple platforms and debug_names elsewhere.
+  if (DwarfVersion >= 5)
+    return AccelTableKind::Dwarf;
+  if (Tuning == DebuggerKind::LLDB)
+    return TT.isOSBinFormatMachO() ? AccelTableKind::Apple
+                                   : AccelTableKind::Dwarf;
+  return AccelTableKind::None;
+}
+
 DwarfDebug::DwarfDebug(AsmPrinter *A, Module *M)
     : DebugHandlerBase(A), DebugLocs(A->OutStreamer->isVerboseAsm()),
       InfoHolder(A, "info_string", DIEValueAllocator),
@@ -302,16 +330,6 @@ DwarfDebug::DwarfDebug(AsmPrinter *A, Module *M)
   else
     DebuggerTuning = DebuggerKind::GDB;
 
-  // Turn on accelerator tables by default, if tuning for LLDB and the target is
-  // supported.
-  if (AccelTables == AccelTableKind::Default) {
-    if (tuneForLLDB() && A->TM.getTargetTriple().isOSBinFormatMachO())
-      TheAccelTableKind = AccelTableKind::Apple;
-    else
-      TheAccelTableKind = AccelTableKind::None;
-  } else
-    TheAccelTableKind = AccelTables;
-
   if (DwarfInlinedStrings == Default)
     UseInlineStrings = TT.isNVPTX();
   else
@@ -346,6 +364,11 @@ DwarfDebug::DwarfDebug(AsmPrinter *A, Module *M)
   else
     UseSectionsAsReferences = DwarfSectionsAsReferences == Enable;
 
+  GenerateTypeUnits = GenerateDwarfTypeUnits;
+
+  TheAccelTableKind = computeAccelTableKind(
+      DwarfVersion, GenerateTypeUnits, DebuggerTuning, A->TM.getTargetTriple());
+
   // Work around a GDB bug. GDB doesn't support the standard opcode;
   // SCE doesn't support GNU's; LLDB prefers the standard opcode, which
   // is defined as of DWARF 3.
diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.h b/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.h
index 42988d53b8b..6f4cefe6107 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.h
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.h
@@ -279,6 +279,9 @@ class DwarfDebug : public DebugHandlerBase {
   ///Allow emission of the .debug_loc section.
   bool UseLocSection = true;
 
+  /// Generate DWARF v4 type units.
+  bool GenerateTypeUnits;
+
   /// DWARF5 Experimental Options
   /// @{
   AccelTableKind TheAccelTableKind;
@@ -546,6 +549,9 @@ public:
   /// Returns whether .debug_loc section should be emitted.
   bool useLocSection() const { return UseLocSection; }
 
+  /// Returns whether to generate DWARF v4 type units.
+  bool generateTypeUnits() const { return GenerateTypeUnits; }
+
   // Experimental DWARF5 features.
 
   /// Returns what kind (if any) of accelerator tables to emit.
diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp b/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp
index 9af555464d4..43b835b2c4a 100644
--- a/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp
+++ b/llvm/lib/CodeGen/AsmPrinter/DwarfUnit.cpp
@@ -47,11 +47,6 @@ using namespace llvm;
 
 #define DEBUG_TYPE "dwarfdebug"
 
-static cl::opt<bool>
-GenerateDwarfTypeUnits("generate-type-units", cl::Hidden,
-                       cl::desc("Generate DWARF4 type units."),
-                       cl::init(false));
-
 DIEDwarfExpression::DIEDwarfExpression(const AsmPrinter &AP, DwarfUnit &DU,
                                        DIELoc &DIE)
     : DwarfExpression(AP.getDwarfVersion()), AP(AP), DU(DU),
@@ -185,7 +180,7 @@ bool DwarfUnit::isShareableAcrossCUs(const DINode *D) const {
     return false;
   return (isa<DIType>(D) ||
           (isa<DISubprogram>(D) && !cast<DISubprogram>(D)->isDefinition())) &&
-         !GenerateDwarfTypeUnits;
+         !DD->generateTypeUnits();
 }
 
 DIE *DwarfUnit::getDIE(const DINode *D) const {
@@ -768,7 +763,7 @@ DIE *DwarfUnit::getOrCreateTypeDIE(const MDNode *TyNode) {
   else if (auto *STy = dyn_cast<DISubroutineType>(Ty))
     constructTypeDIE(TyDIE, STy);
   else if (auto *CTy = dyn_cast<DICompositeType>(Ty)) {
-    if (GenerateDwarfTypeUnits && !Ty->isForwardDecl())
+    if (DD->generateTypeUnits() && !Ty->isForwardDecl())
       if (MDString *TypeId = CTy->getRawIdentifier()) {
         DD->addDwarfTypeUnitType(getCU(), TypeId->getString(), TyDIE, CTy);
         // Skip updating the accelerator tables since this is not the full type.