PR14728: DebugInfo: TLS variables with -gsplit-dwarf

llvm-svn: 185398

lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp

@@ -201,15 +201,12 @@ void CompileUnit::addLabelAddress(DIE *Die, unsigned Attribute,
 /// form given and an op of either DW_FORM_addr or DW_FORM_GNU_addr_index.
 ///
 void CompileUnit::addOpAddress(DIE *Die, const MCSymbol *Sym) {
-
   if (!DD->useSplitDwarf()) {
     addUInt(Die, 0, dwarf::DW_FORM_data1, dwarf::DW_OP_addr);
     addLabel(Die, 0, dwarf::DW_FORM_udata, Sym);
   } else {
-    unsigned idx = DU->getAddrPoolIndex(Sym);
-    DIEValue *Value = new (DIEValueAllocator) DIEInteger(idx);
     addUInt(Die, 0, dwarf::DW_FORM_data1, dwarf::DW_OP_GNU_addr_index);
-    Die->addValue(0, dwarf::DW_FORM_GNU_addr_index, Value);
+    addUInt(Die, 0, dwarf::DW_FORM_GNU_addr_index, DU->getAddrPoolIndex(Sym));
   }
 }
 
@@ -1358,13 +1355,19 @@ void CompileUnit::createGlobalVariableDIE(const MDNode *N) {
       unsigned PointerSize = Asm->getDataLayout().getPointerSize();
       assert((PointerSize == 4 || PointerSize == 8) &&
              "Add support for other sizes if necessary");
+      const MCSymbolRefExpr *Ref =
+          Asm->getObjFileLowering().getDebugThreadLocalSymbol(Sym);
       // Based on GCC's support for TLS:
-      // 1) Start with a constNu of the appropriate pointer size
-      addUInt(Block, 0, dwarf::DW_FORM_data1,
-              PointerSize == 4 ? dwarf::DW_OP_const4u : dwarf::DW_OP_const8u);
-      // 2) containing the (relocated) address of the TLS variable
-      addLabel(Block, 0, dwarf::DW_FORM_udata,
-               Asm->getObjFileLowering().getDebugThreadLocalSymbol(Sym));
+      if (!DD->useSplitDwarf()) {
+        // 1) Start with a constNu of the appropriate pointer size
+        addUInt(Block, 0, dwarf::DW_FORM_data1,
+                PointerSize == 4 ? dwarf::DW_OP_const4u : dwarf::DW_OP_const8u);
+        // 2) containing the (relocated) address of the TLS variable
+        addLabel(Block, 0, dwarf::DW_FORM_udata, Ref);
+      } else {
+        addUInt(Block, 0, dwarf::DW_FORM_data1, dwarf::DW_OP_GNU_const_index);
+        addUInt(Block, 0, dwarf::DW_FORM_udata, DU->getAddrPoolIndex(Ref));
+      }
       // 3) followed by a custom OP to tell the debugger about TLS (presumably)
       addUInt(Block, 0, dwarf::DW_FORM_data1, dwarf::DW_OP_lo_user);
     } else

lib/CodeGen/AsmPrinter/DwarfDebug.cpp

@@ -248,7 +248,11 @@ unsigned DwarfUnits::getStringPoolIndex(StringRef Str) {
 }
 
 unsigned DwarfUnits::getAddrPoolIndex(const MCSymbol *Sym) {
-  std::pair<DenseMap<const MCSymbol *, unsigned>::iterator, bool> P =
+  return getAddrPoolIndex(MCSymbolRefExpr::Create(Sym, Asm->OutContext));
+}
+
+unsigned DwarfUnits::getAddrPoolIndex(const MCSymbolRefExpr *Sym) {
+  std::pair<DenseMap<const MCSymbolRefExpr *, unsigned>::iterator, bool> P =
       AddressPool.insert(std::make_pair(Sym, NextAddrPoolNumber));
   if (P.second)
     ++NextAddrPoolNumber;
@@ -2357,10 +2361,11 @@ void DwarfUnits::emitAddresses(const MCSection *AddrSection) {
 
   // Get all of the address pool entries and put them in an array by their ID so
   // we can sort them.
-  SmallVector<std::pair<unsigned, const MCSymbol *>, 64> Entries;
+  SmallVector<std::pair<unsigned, const MCSymbolRefExpr *>, 64> Entries;
 
-  for (DenseMap<const MCSymbol *, unsigned>::iterator I = AddressPool.begin(),
-                                                      E = AddressPool.end();
+  for (DenseMap<const MCSymbolRefExpr *, unsigned>::iterator
+           I = AddressPool.begin(),
+           E = AddressPool.end();
        I != E; ++I)
     Entries.push_back(std::make_pair(I->second, I->first));
 
@@ -2368,8 +2373,8 @@ void DwarfUnits::emitAddresses(const MCSection *AddrSection) {
 
   for (unsigned i = 0, e = Entries.size(); i != e; ++i) {
     // Emit a label for reference from debug information entries.
-    if (const MCSymbol *Sym = Entries[i].second)
-      Asm->EmitLabelReference(Sym, Asm->getDataLayout().getPointerSize());
+    if (const MCSymbolRefExpr *Sym = Entries[i].second)
+      Asm->OutStreamer.EmitValue(Sym, Asm->getDataLayout().getPointerSize());
     else
       Asm->OutStreamer.EmitIntValue(0, Asm->getDataLayout().getPointerSize());
   }

lib/CodeGen/AsmPrinter/DwarfDebug.h

@@ -197,7 +197,7 @@ typedef StringMap<std::pair<MCSymbol*, unsigned>,
 
 // A Symbol->unsigned mapping of addresses used by indirect
 // references.
-typedef DenseMap<const MCSymbol *, unsigned> AddrPool;
+typedef DenseMap<const MCSymbolRefExpr *, unsigned> AddrPool;
 
 /// \brief Collects and handles information specific to a particular
 /// collection of units.
@@ -270,6 +270,7 @@ public:
 
   /// \brief Returns the index into the address pool with the given
   /// label/symbol.
+  unsigned getAddrPoolIndex(const MCSymbolRefExpr *);
   unsigned getAddrPoolIndex(const MCSymbol *);
 
   /// \brief Returns the address pool.

test/DebugInfo/X86/tls-fission.ll

@@ -0,0 +1,31 @@
+; RUN: llc -split-dwarf=Enable -mtriple=x86_64-linux -O0 -filetype=asm < %s | FileCheck %s
+
+; FIXME: add relocation and DWARF expression support to llvm-dwarfdump & use
+; that here instead of raw assembly printing
+
+; CHECK: debug_info.dwo
+; 3 bytes of data in this DW_FORM_block1 representation of the location of 'tls'
+; CHECK: .byte 3{{ *}}# DW_AT_location
+; DW_OP_const_index (0xfx == 252) to refer to the debug_addr table
+; CHECK-NEXT: .byte 252
+; an index of zero into the debug_addr table
+; CHECK-NEXT: .byte 0
+; DW_OP_lo_user based on GCC/GDB extension presumably (by experiment) to support TLS
+; CHECK-NEXT: .byte 224
+; check that the expected TLS address description is the first thing in the debug_addr section
+; CHECK: debug_addr
+; CHECK-NEXT: .quad	tls@DTPOFF
+
+@tls = thread_local global i32 0, align 4
+
+!llvm.dbg.cu = !{!0}
+!llvm.module.flags = !{!7}
+
+!0 = metadata !{i32 786449, metadata !1, i32 4, metadata !"clang version 3.4 ", i1 false, metadata !"", i32 0, metadata !2, metadata !2, metadata !2, metadata !3, metadata !2, metadata !"tls.dwo"} ; [ DW_TAG_compile_unit ] [/tmp/tls.cpp] [DW_LANG_C_plus_plus]
+!1 = metadata !{metadata !"tls.cpp", metadata !"/tmp"}
+!2 = metadata !{i32 0}
+!3 = metadata !{metadata !4}
+!4 = metadata !{i32 786484, i32 0, null, metadata !"tls", metadata !"tls", metadata !"", metadata !5, i32 1, metadata !6, i32 0, i32 1, i32* @tls, null} ; [ DW_TAG_variable ] [tls] [line 1] [def]
+!5 = metadata !{i32 786473, metadata !1}          ; [ DW_TAG_file_type ] [/tmp/tls.cpp]
+!6 = metadata !{i32 786468, null, null, metadata !"int", i32 0, i64 32, i64 32, i64 0, i32 0, i32 5} ; [ DW_TAG_base_type ] [int] [line 0, size 32, align 32, offset 0, enc DW_ATE_signed]
+!7 = metadata !{i32 2, metadata !"Dwarf Version", i32 3}