From ce20d460e2a96c05ff8a2d5a6d57d6a6ef5a1cfa Mon Sep 17 00:00:00 2001 From: Manman Ren Date: Tue, 29 Oct 2013 22:57:10 +0000 Subject: [PATCH] Debug Info: support for DW_FORM_ref_addr. To support ref_addr, we calculate the section offset of a DIE (i.e. offset of a DIE from beginning of the debug info section). The Offset field in DIE is currently CU-relative. To calculate the section offset, we add a DebugInfoOffset field in CompileUnit to store the offset of a CU from beginning of the debug info section. We set the value in DwarfUnits::computeSizeAndOffset for each CompileUnit. A helper function DIE::getCompileUnit is added to return the CU DIE that the input DIE belongs to. We also add a map CUDieMap in DwarfDebug to help finding the CU for a given CU DIE. For a cross-referenced DIE, we first find the CU DIE it belongs to with getCompileUnit, then we use CUDieMap to get the corresponding CU for the CU DIE. Adding the section offset of the CU with the CU-relative offset of a DIE gives us the seciton offset of the DIE. We correctly emit ref_addr with relocation using EmitLabelPlusOffset when doesDwarfUseRelocationsAcrossSections is true. This commit handles the emission of DW_FORM_ref_addr when we have an attribute with FORM_ref_addr. A follow-on patch will start using ref_addr when adding a DIEEntry. This commit will be tested and verified in the follow-on patch. Reviewed off-list by Eric, Thanks. llvm-svn: 193658 --- llvm/lib/CodeGen/AsmPrinter/DIE.cpp | 12 ++++++ llvm/lib/CodeGen/AsmPrinter/DIE.h | 3 ++ .../CodeGen/AsmPrinter/DwarfCompileUnit.cpp | 3 +- .../lib/CodeGen/AsmPrinter/DwarfCompileUnit.h | 6 +++ llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp | 43 ++++++++++++++++++- llvm/lib/CodeGen/AsmPrinter/DwarfDebug.h | 3 ++ 6 files changed, 67 insertions(+), 3 deletions(-) diff --git a/llvm/lib/CodeGen/AsmPrinter/DIE.cpp b/llvm/lib/CodeGen/AsmPrinter/DIE.cpp index f9bf8b98a601..334c10831612 100644 --- a/llvm/lib/CodeGen/AsmPrinter/DIE.cpp +++ b/llvm/lib/CodeGen/AsmPrinter/DIE.cpp @@ -112,6 +112,18 @@ DIE::~DIE() { delete Children[i]; } +/// Climb up the parent chain to get the compile unit DIE to which this DIE +/// belongs. +const DIE *DIE::getCompileUnit() const { + const DIE *p = this; + while (p) { + if (p->getTag() == dwarf::DW_TAG_compile_unit) + return p; + p = p->getParent(); + } + llvm_unreachable("We should not have orphaned DIEs."); +} + DIEValue *DIE::findAttribute(uint16_t Attribute) { const SmallVectorImpl &Values = getValues(); const DIEAbbrev &Abbrevs = getAbbrev(); diff --git a/llvm/lib/CodeGen/AsmPrinter/DIE.h b/llvm/lib/CodeGen/AsmPrinter/DIE.h index 6d4f305c8400..96a01327f769 100644 --- a/llvm/lib/CodeGen/AsmPrinter/DIE.h +++ b/llvm/lib/CodeGen/AsmPrinter/DIE.h @@ -146,6 +146,9 @@ namespace llvm { const std::vector &getChildren() const { return Children; } const SmallVectorImpl &getValues() const { return Values; } DIE *getParent() const { return Parent; } + /// Climb up the parent chain to get the compile unit DIE this DIE belongs + /// to. + const DIE *getCompileUnit() const; void setOffset(unsigned O) { Offset = O; } void setSize(unsigned S) { Size = S; } diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp b/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp index db8558cfeca3..27ba19a89647 100644 --- a/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp +++ b/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.cpp @@ -33,7 +33,8 @@ using namespace llvm; /// CompileUnit - Compile unit constructor. CompileUnit::CompileUnit(unsigned UID, DIE *D, const MDNode *N, AsmPrinter *A, DwarfDebug *DW, DwarfUnits *DWU) - : UniqueID(UID), Node(N), CUDie(D), Asm(A), DD(DW), DU(DWU), IndexTyDie(0) { + : UniqueID(UID), Node(N), CUDie(D), Asm(A), DD(DW), DU(DWU), IndexTyDie(0), + DebugInfoOffset(0) { DIEIntegerOne = new (DIEValueAllocator) DIEInteger(1); insertDIE(N, D); } diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.h b/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.h index 1759ac4bdaa1..4a59ec544de4 100644 --- a/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.h +++ b/llvm/lib/CodeGen/AsmPrinter/DwarfCompileUnit.h @@ -120,6 +120,9 @@ public: return AccelTypes; } + unsigned getDebugInfoOffset() const { return DebugInfoOffset; } + void setDebugInfoOffset(unsigned DbgInfoOff) { DebugInfoOffset = DbgInfoOff; } + /// hasContent - Return true if this compile unit has something to write out. /// bool hasContent() const { return !CUDie->getChildren().empty(); } @@ -347,6 +350,9 @@ private: /// getOrCreateStaticMemberDIE - Create new static data member DIE. DIE *getOrCreateStaticMemberDIE(DIDerivedType DT); + /// Offset of the CUDie from beginning of debug info section. + unsigned DebugInfoOffset; + /// getLowerBoundDefault - Return the default lower bound for an array. If the /// DWARF version doesn't handle the language, return -1. int64_t getDefaultLowerBound() const; diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp b/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp index f491d01876c7..722dd32d7edc 100644 --- a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp +++ b/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.cpp @@ -821,6 +821,7 @@ CompileUnit *DwarfDebug::constructCompileUnit(const MDNode *N) { InfoHolder.addUnit(NewCU); CUMap.insert(std::make_pair(N, NewCU)); + CUDieMap.insert(std::make_pair(Die, NewCU)); return NewCU; } @@ -1915,7 +1916,8 @@ void DwarfDebug::recordSourceLine(unsigned Line, unsigned Col, const MDNode *S, // Emit Methods //===----------------------------------------------------------------------===// -// Compute the size and offset of a DIE. +// Compute the size and offset of a DIE. The offset is relative to start of the +// CU. It returns the offset after laying out the DIE. unsigned DwarfUnits::computeSizeAndOffset(DIE *Die, unsigned Offset) { // Get the children. @@ -1960,16 +1962,26 @@ DwarfUnits::computeSizeAndOffset(DIE *Die, unsigned Offset) { // Compute the size and offset for each DIE. void DwarfUnits::computeSizeAndOffsets() { + // Offset from the first CU in the debug info section is 0 initially. + unsigned SecOffset = 0; + // Iterate over each compile unit and set the size and offsets for each // DIE within each compile unit. All offsets are CU relative. for (SmallVectorImpl::iterator I = CUs.begin(), E = CUs.end(); I != E; ++I) { + (*I)->setDebugInfoOffset(SecOffset); + + // CU-relative offset is reset to 0 here. unsigned Offset = sizeof(int32_t) + // Length of Compilation Unit Info sizeof(int16_t) + // DWARF version number sizeof(int32_t) + // Offset Into Abbrev. Section sizeof(int8_t); // Pointer Size (in bytes) - computeSizeAndOffset((*I)->getCUDie(), Offset); + + // EndOffset here is CU-relative, after laying out + // all of the CU DIE. + unsigned EndOffset = computeSizeAndOffset((*I)->getCUDie(), Offset); + SecOffset += EndOffset; } } @@ -2049,6 +2061,33 @@ void DwarfDebug::emitDIE(DIE *Die, std::vector *Abbrevs) { Asm->OutStreamer.AddComment(dwarf::AttributeString(Attr)); switch (Attr) { + case dwarf::DW_AT_abstract_origin: + case dwarf::DW_AT_type: + case dwarf::DW_AT_friend: + case dwarf::DW_AT_specification: + case dwarf::DW_AT_import: + case dwarf::DW_AT_containing_type: { + DIEEntry *E = cast(Values[i]); + DIE *Origin = E->getEntry(); + unsigned Addr = Origin->getOffset(); + if (Form == dwarf::DW_FORM_ref_addr) { + assert(!useSplitDwarf() && "TODO: dwo files can't have relocations."); + // For DW_FORM_ref_addr, output the offset from beginning of debug info + // section. Origin->getOffset() returns the offset from start of the + // compile unit. + CompileUnit *CU = CUDieMap.lookup(Origin->getCompileUnit()); + assert(CU && "CUDie should belong to a CU."); + Addr += CU->getDebugInfoOffset(); + if (Asm->MAI->doesDwarfUseRelocationsAcrossSections()) + Asm->EmitLabelPlusOffset(DwarfInfoSectionSym, Addr, + DIEEntry::getRefAddrSize(Asm)); + else + Asm->OutStreamer.EmitIntValue(Addr, DIEEntry::getRefAddrSize(Asm)); + } else { + Asm->EmitInt32(Addr); + } + break; + } case dwarf::DW_AT_ranges: { // DW_AT_range Value encodes offset in debug_range section. DIEInteger *V = cast(Values[i]); diff --git a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.h b/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.h index 83ea0cc967ad..d3ce12c67a9b 100644 --- a/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.h +++ b/llvm/lib/CodeGen/AsmPrinter/DwarfDebug.h @@ -329,6 +329,9 @@ class DwarfDebug { // Maps subprogram MDNode with its corresponding CompileUnit. DenseMap SPMap; + // Maps a CU DIE with its corresponding CompileUnit. + DenseMap CUDieMap; + // Used to uniquely define abbreviations. FoldingSet AbbreviationsSet;