From 59eaa3874663f80ce111a4781b8f1db82995210c Mon Sep 17 00:00:00 2001 From: David Blaikie Date: Fri, 28 Jun 2013 20:05:11 +0000 Subject: DebugInfo: PR14728: TLS support Based on GCC's output for TLS variables (OP_constNu, x@dtpoff, OP_lo_user), this implements debug info support for TLS in ELF. Verified that this output is correct/sufficient on Linux (using gold - if you're using binutils-ld, you'll need something with the fix for http://sourceware.org/bugzilla/show_bug.cgi?id=15685 in it). Support on non-ELF is sort of "arbitrary" at the moment - if Apple folks want to discuss (or just go ahead & implement) how this should work in MachO, etc, I'm open. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@185203 91177308-0d34-0410-b5e6-96231b3b80d8 --- .../llvm/CodeGen/TargetLoweringObjectFileImpl.h | 3 ++ include/llvm/Target/TargetLoweringObjectFile.h | 4 +++ lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp | 21 +++++++++++-- lib/CodeGen/TargetLoweringObjectFileImpl.cpp | 4 +++ lib/Target/TargetLoweringObjectFile.cpp | 6 ++++ test/DebugInfo/X86/tls.ll | 34 ++++++++++++++++++++++ 6 files changed, 69 insertions(+), 3 deletions(-) create mode 100644 test/DebugInfo/X86/tls.ll diff --git a/include/llvm/CodeGen/TargetLoweringObjectFileImpl.h b/include/llvm/CodeGen/TargetLoweringObjectFileImpl.h index 5b22c9c..5e11ecf 100644 --- a/include/llvm/CodeGen/TargetLoweringObjectFileImpl.h +++ b/include/llvm/CodeGen/TargetLoweringObjectFileImpl.h @@ -72,6 +72,9 @@ public: getStaticCtorSection(unsigned Priority = 65535) const; virtual const MCSection * getStaticDtorSection(unsigned Priority = 65535) const; + + /// \brief Describe a TLS variable address within debug info. + virtual const MCSymbolRefExpr *getDebugThreadLocalSymbol(const MCSymbol *Sym) const; }; diff --git a/include/llvm/Target/TargetLoweringObjectFile.h b/include/llvm/Target/TargetLoweringObjectFile.h index 9958755..a17feeb 100644 --- a/include/llvm/Target/TargetLoweringObjectFile.h +++ b/include/llvm/Target/TargetLoweringObjectFile.h @@ -138,6 +138,10 @@ public: return StaticDtorSection; } + /// \brief Create a symbol reference to describe the given TLS variable when + /// emitting the address in debug info. + virtual const MCSymbolRefExpr *getDebugThreadLocalSymbol(const MCSymbol *Sym) const; + protected: virtual const MCSection * SelectSectionForGlobal(const GlobalValue *GV, SectionKind Kind, diff --git a/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp b/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp index 6bd4f08..339a5d2 100644 --- a/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp +++ b/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp @@ -27,6 +27,7 @@ #include "llvm/Target/Mangler.h" #include "llvm/Target/TargetFrameLowering.h" #include "llvm/Target/TargetMachine.h" +#include "llvm/Target/TargetLoweringObjectFile.h" #include "llvm/Target/TargetRegisterInfo.h" using namespace llvm; @@ -1351,7 +1352,23 @@ void CompileUnit::createGlobalVariableDIE(const MDNode *N) { if (isGlobalVariable) { addToAccelTable = true; DIEBlock *Block = new (DIEValueAllocator) DIEBlock(); - addOpAddress(Block, Asm->Mang->getSymbol(GV.getGlobal())); + const MCSymbol *Sym = Asm->Mang->getSymbol(GV.getGlobal()); + if (GV.getGlobal()->isThreadLocal()) { + // FIXME: Make this work with -gsplit-dwarf. + unsigned PointerSize = Asm->getDataLayout().getPointerSize(); + assert((PointerSize == 4 || PointerSize == 8) && + "Add support for other sizes if necessary"); + // 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)); + // 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 + addOpAddress(Block, Sym); // Do not create specification DIE if context is either compile unit // or a subprogram. if (GVContext && GV.isDefinition() && !GVContext.isCompileUnit() && @@ -1413,8 +1430,6 @@ void CompileUnit::createGlobalVariableDIE(const MDNode *N) { if (GV.getLinkageName() != "" && GV.getName() != GV.getLinkageName()) addAccelName(GV.getLinkageName(), AddrDIE); } - - return; } /// constructSubrangeDIE - Construct subrange DIE from DISubrange. diff --git a/lib/CodeGen/TargetLoweringObjectFileImpl.cpp b/lib/CodeGen/TargetLoweringObjectFileImpl.cpp index 7e7359a..69d5591 100644 --- a/lib/CodeGen/TargetLoweringObjectFileImpl.cpp +++ b/lib/CodeGen/TargetLoweringObjectFileImpl.cpp @@ -401,6 +401,10 @@ TargetLoweringObjectFileELF::InitializeELF(bool UseInitArray_) { SectionKind::getDataRel()); } +const MCSymbolRefExpr *TargetLoweringObjectFileELF::getDebugThreadLocalSymbol(const MCSymbol *Sym) const { + return MCSymbolRefExpr::Create(Sym, MCSymbolRefExpr::VK_DTPOFF, getContext()); +} + //===----------------------------------------------------------------------===// // MachO //===----------------------------------------------------------------------===// diff --git a/lib/Target/TargetLoweringObjectFile.cpp b/lib/Target/TargetLoweringObjectFile.cpp index f5121e3..fc50aa5 100644 --- a/lib/Target/TargetLoweringObjectFile.cpp +++ b/lib/Target/TargetLoweringObjectFile.cpp @@ -317,3 +317,9 @@ getTTypeReference(const MCSymbolRefExpr *Sym, unsigned Encoding, } } } + +const MCSymbolRefExpr *TargetLoweringObjectFile::getDebugThreadLocalSymbol(const MCSymbol *Sym) const { + // FIXME: It's not clear what, if any, default this should have - perhaps a + // null return could mean 'no location' & we should just do that here. + return MCSymbolRefExpr::Create(Sym, *Ctx); +} diff --git a/test/DebugInfo/X86/tls.ll b/test/DebugInfo/X86/tls.ll new file mode 100644 index 0000000..2ed673a --- /dev/null +++ b/test/DebugInfo/X86/tls.ll @@ -0,0 +1,34 @@ +; RUN: llc -mtriple=x86_64-unknown-unknown -O0 -filetype=asm < %s | FileCheck %s +; RUN: llc -mtriple=i386-unknown-unknown -O0 -filetype=asm < %s | FileCheck --check-prefix=CHECK-32 %s + +; FIXME: add relocation and DWARF expression support to llvm-dwarfdump & use +; that here instead of raw assembly printing + +; 10 bytes of data in this DW_FORM_block1 representation of the location of 'tls' +; CHECK: .byte 10{{ *}}# DW_AT_location +; DW_OP_const8u (0x0e == 14) of adress +; CHECK: .byte 14 +; The debug relocation of the address of the tls variable +; CHECK: .quad tls@DTPOFF +; DW_OP_lo_user based on GCC/GDB extension presumably (by experiment) to support TLS +; CHECK: .byte 224 + +; same again, except with a 32 bit address +; CHECK-32: .byte 6{{ *}}# DW_AT_location +; CHECK-32: .byte 12 +; CHECK-32: .long tls@DTPOFF +; CHECK-32: .byte 224 + +@tls = thread_local global i32 7, 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 !""} ; [ 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} -- cgit v1.1