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-rw-r--r--lld/MachO/CMakeLists.txt1
-rw-r--r--lld/MachO/Dwarf.cpp49
-rw-r--r--lld/MachO/Dwarf.h53
-rw-r--r--lld/MachO/InputFiles.cpp24
-rw-r--r--lld/MachO/InputFiles.h6
-rw-r--r--lld/MachO/InputSection.h9
-rw-r--r--lld/MachO/OutputSegment.h1
-rw-r--r--lld/MachO/SyntheticSections.cpp104
-rw-r--r--lld/MachO/SyntheticSections.h23
-rw-r--r--lld/MachO/Writer.cpp7
-rw-r--r--lld/test/MachO/stabs.s114
11 files changed, 383 insertions, 8 deletions
diff --git a/lld/MachO/CMakeLists.txt b/lld/MachO/CMakeLists.txt
index 6ddc88fb8618..6a8b5d336583 100644
--- a/lld/MachO/CMakeLists.txt
+++ b/lld/MachO/CMakeLists.txt
@@ -9,6 +9,7 @@ add_lld_library(lldMachO2
UnwindInfoSection.cpp
Driver.cpp
DriverUtils.cpp
+ Dwarf.cpp
ExportTrie.cpp
InputFiles.cpp
InputSection.cpp
diff --git a/lld/MachO/Dwarf.cpp b/lld/MachO/Dwarf.cpp
new file mode 100644
index 000000000000..121f54fb1f79
--- /dev/null
+++ b/lld/MachO/Dwarf.cpp
@@ -0,0 +1,49 @@
+//===- DWARF.cpp ----------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "Dwarf.h"
+#include "InputFiles.h"
+#include "InputSection.h"
+#include "OutputSegment.h"
+
+#include <memory>
+
+using namespace lld;
+using namespace lld::macho;
+using namespace llvm;
+
+std::unique_ptr<DwarfObject> DwarfObject::create(ObjFile *obj) {
+ auto dObj = std::make_unique<DwarfObject>();
+ bool hasDwarfInfo = false;
+ for (SubsectionMap subsecMap : obj->subsections) {
+ for (auto it : subsecMap) {
+ InputSection *isec = it.second;
+ if (!(isDebugSection(isec->flags) &&
+ isec->segname == segment_names::dwarf))
+ continue;
+
+ if (isec->name == "__debug_info") {
+ dObj->infoSection.Data = toStringRef(isec->data);
+ hasDwarfInfo = true;
+ continue;
+ }
+
+ if (StringRef *s = StringSwitch<StringRef *>(isec->name)
+ .Case("__debug_abbrev", &dObj->abbrevSection)
+ .Case("__debug_str", &dObj->strSection)
+ .Default(nullptr)) {
+ *s = toStringRef(isec->data);
+ hasDwarfInfo = true;
+ }
+ }
+ }
+
+ if (hasDwarfInfo)
+ return dObj;
+ return nullptr;
+}
diff --git a/lld/MachO/Dwarf.h b/lld/MachO/Dwarf.h
new file mode 100644
index 000000000000..119f2778fc6b
--- /dev/null
+++ b/lld/MachO/Dwarf.h
@@ -0,0 +1,53 @@
+//===- DWARF.h -----------------------------------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===-------------------------------------------------------------------===//
+
+#ifndef LLD_MACHO_DWARF_H
+#define LLD_MACHO_DWARF_H
+
+#include "llvm/ADT/StringRef.h"
+#include "llvm/DebugInfo/DWARF/DWARFObject.h"
+
+namespace lld {
+namespace macho {
+
+class ObjFile;
+
+// Implements the interface between LLVM's DWARF-parsing utilities and LLD's
+// InputSection structures.
+class DwarfObject final : public llvm::DWARFObject {
+public:
+ bool isLittleEndian() const override { return true; }
+
+ llvm::Optional<llvm::RelocAddrEntry> find(const llvm::DWARFSection &sec,
+ uint64_t pos) const override {
+ // TODO: implement this
+ return llvm::None;
+ }
+
+ void forEachInfoSections(
+ llvm::function_ref<void(const llvm::DWARFSection &)> f) const override {
+ f(infoSection);
+ }
+
+ llvm::StringRef getAbbrevSection() const override { return abbrevSection; }
+ llvm::StringRef getStrSection() const override { return strSection; }
+
+ // Returns an instance of DwarfObject if the given object file has the
+ // relevant DWARF debug sections.
+ static std::unique_ptr<DwarfObject> create(ObjFile *);
+
+private:
+ llvm::DWARFSection infoSection;
+ llvm::StringRef abbrevSection;
+ llvm::StringRef strSection;
+};
+
+} // namespace macho
+} // namespace lld
+
+#endif
diff --git a/lld/MachO/InputFiles.cpp b/lld/MachO/InputFiles.cpp
index 2f65951a49c7..921b69995d43 100644
--- a/lld/MachO/InputFiles.cpp
+++ b/lld/MachO/InputFiles.cpp
@@ -44,6 +44,7 @@
#include "InputFiles.h"
#include "Config.h"
#include "Driver.h"
+#include "Dwarf.h"
#include "ExportTrie.h"
#include "InputSection.h"
#include "MachOStructs.h"
@@ -54,6 +55,7 @@
#include "Symbols.h"
#include "Target.h"
+#include "lld/Common/DWARF.h"
#include "lld/Common/ErrorHandler.h"
#include "lld/Common/Memory.h"
#include "lld/Common/Reproduce.h"
@@ -387,6 +389,28 @@ ObjFile::ObjFile(MemoryBufferRef mb) : InputFile(ObjKind, mb) {
// parsed all the symbols.
for (size_t i = 0, n = subsections.size(); i < n; ++i)
parseRelocations(sectionHeaders[i], subsections[i]);
+
+ parseDebugInfo();
+}
+
+void ObjFile::parseDebugInfo() {
+ std::unique_ptr<DwarfObject> dObj = DwarfObject::create(this);
+ if (!dObj)
+ return;
+
+ auto *ctx = make<DWARFContext>(
+ std::move(dObj), "",
+ [&](Error err) { warn(getName() + ": " + toString(std::move(err))); },
+ [&](Error warning) {
+ warn(getName() + ": " + toString(std::move(warning)));
+ });
+
+ // TODO: Since object files can contain a lot of DWARF info, we should verify
+ // that we are parsing just the info we need
+ const DWARFContext::compile_unit_range &units = ctx->compile_units();
+ auto it = units.begin();
+ compileUnit = it->get();
+ assert(std::next(it) == units.end());
}
// The path can point to either a dylib or a .tbd file.
diff --git a/lld/MachO/InputFiles.h b/lld/MachO/InputFiles.h
index a1405aa66ea2..4356350e7c17 100644
--- a/lld/MachO/InputFiles.h
+++ b/lld/MachO/InputFiles.h
@@ -15,6 +15,7 @@
#include "lld/Common/Memory.h"
#include "llvm/ADT/DenseSet.h"
#include "llvm/BinaryFormat/MachO.h"
+#include "llvm/DebugInfo/DWARF/DWARFUnit.h"
#include "llvm/Object/Archive.h"
#include "llvm/Support/MemoryBuffer.h"
#include "llvm/TextAPI/MachO/InterfaceFile.h"
@@ -91,6 +92,11 @@ class ObjFile : public InputFile {
public:
explicit ObjFile(MemoryBufferRef mb);
static bool classof(const InputFile *f) { return f->kind() == ObjKind; }
+
+ llvm::DWARFUnit *compileUnit = nullptr;
+
+private:
+ void parseDebugInfo();
};
// command-line -sectcreate file
diff --git a/lld/MachO/InputSection.h b/lld/MachO/InputSection.h
index 1449c87dceb5..4ef8d84bc8a0 100644
--- a/lld/MachO/InputSection.h
+++ b/lld/MachO/InputSection.h
@@ -35,15 +35,20 @@ struct Reloc {
llvm::PointerUnion<Symbol *, InputSection *> referent;
};
-inline bool isZeroFill(uint8_t flags) {
+inline bool isZeroFill(uint32_t flags) {
return llvm::MachO::isVirtualSection(flags & llvm::MachO::SECTION_TYPE);
}
-inline bool isThreadLocalVariables(uint8_t flags) {
+inline bool isThreadLocalVariables(uint32_t flags) {
return (flags & llvm::MachO::SECTION_TYPE) ==
llvm::MachO::S_THREAD_LOCAL_VARIABLES;
}
+inline bool isDebugSection(uint32_t flags) {
+ return (flags & llvm::MachO::SECTION_ATTRIBUTES_USR) ==
+ llvm::MachO::S_ATTR_DEBUG;
+}
+
class InputSection {
public:
virtual ~InputSection() = default;
diff --git a/lld/MachO/OutputSegment.h b/lld/MachO/OutputSegment.h
index 62342370bf81..63b62d5e9109 100644
--- a/lld/MachO/OutputSegment.h
+++ b/lld/MachO/OutputSegment.h
@@ -23,6 +23,7 @@ constexpr const char data[] = "__DATA";
constexpr const char linkEdit[] = "__LINKEDIT";
constexpr const char dataConst[] = "__DATA_CONST";
constexpr const char ld[] = "__LD"; // output only with -r
+constexpr const char dwarf[] = "__DWARF";
} // namespace segment_names
diff --git a/lld/MachO/SyntheticSections.cpp b/lld/MachO/SyntheticSections.cpp
index 5d603d6f90d3..feaa4b5d3e22 100644
--- a/lld/MachO/SyntheticSections.cpp
+++ b/lld/MachO/SyntheticSections.cpp
@@ -20,7 +20,9 @@
#include "lld/Common/ErrorHandler.h"
#include "lld/Common/Memory.h"
#include "llvm/Support/EndianStream.h"
+#include "llvm/Support/FileSystem.h"
#include "llvm/Support/LEB128.h"
+#include "llvm/Support/Path.h"
using namespace llvm;
using namespace llvm::support;
@@ -574,17 +576,100 @@ SymtabSection::SymtabSection(StringTableSection &stringTableSection)
stringTableSection(stringTableSection) {}
uint64_t SymtabSection::getRawSize() const {
- return symbols.size() * sizeof(structs::nlist_64);
+ return getNumSymbols() * sizeof(structs::nlist_64);
+}
+
+void SymtabSection::emitBeginSourceStab(DWARFUnit *compileUnit) {
+ StabsEntry stab(MachO::N_SO);
+ SmallString<261> dir(compileUnit->getCompilationDir());
+ StringRef sep = sys::path::get_separator();
+ // We don't use `path::append` here because we want an empty `dir` to result
+ // in an absolute path. `append` would give us a relative path for that case.
+ if (!dir.endswith(sep))
+ dir += sep;
+ stab.strx = stringTableSection.addString(
+ saver.save(dir + compileUnit->getUnitDIE().getShortName()));
+ stabs.emplace_back(std::move(stab));
+}
+
+void SymtabSection::emitEndSourceStab() {
+ StabsEntry stab(MachO::N_SO);
+ stab.sect = 1;
+ stabs.emplace_back(std::move(stab));
+}
+
+void SymtabSection::emitObjectFileStab(ObjFile *file) {
+ StabsEntry stab(MachO::N_OSO);
+ stab.sect = target->cpuSubtype;
+ SmallString<261> path(file->getName());
+ std::error_code ec = sys::fs::make_absolute(path);
+ if (ec)
+ fatal("failed to get absolute path for " + file->getName());
+
+ stab.strx = stringTableSection.addString(saver.save(path.str()));
+ stab.desc = 1;
+ stabs.emplace_back(std::move(stab));
+}
+
+void SymtabSection::emitFunStabs(Defined *defined) {
+ {
+ StabsEntry stab(MachO::N_FUN);
+ stab.sect = 1;
+ stab.strx = stringTableSection.addString(defined->getName());
+ stab.value = defined->getVA();
+ stabs.emplace_back(std::move(stab));
+ }
+
+ {
+ StabsEntry stab(MachO::N_FUN);
+ // FIXME this should be the size of the symbol. Using the section size in
+ // lieu is only correct if .subsections_via_symbols is set.
+ stab.value = defined->isec->getSize();
+ stabs.emplace_back(std::move(stab));
+ }
}
void SymtabSection::finalizeContents() {
- // TODO support other symbol types
+ InputFile *lastFile = nullptr;
for (Symbol *sym : symtab->getSymbols()) {
+ // TODO support other symbol types
if (isa<Defined>(sym) || sym->isInGot() || sym->isInStubs()) {
sym->symtabIndex = symbols.size();
symbols.push_back({sym, stringTableSection.addString(sym->getName())});
}
+
+ // Emit STABS symbols so that dsymutil and/or the debugger can map address
+ // regions in the final binary to the source and object files from which
+ // they originated.
+ if (auto *defined = dyn_cast<Defined>(sym)) {
+ if (defined->isAbsolute())
+ continue;
+
+ InputSection *isec = defined->isec;
+ // XXX is it right to assume that all symbols in __text are function
+ // symbols?
+ if (isec->name == "__text") {
+ ObjFile *file = dyn_cast<ObjFile>(isec->file);
+ assert(file);
+ if (!file->compileUnit)
+ continue;
+
+ if (lastFile == nullptr || lastFile != file) {
+ if (lastFile != nullptr)
+ emitEndSourceStab();
+ lastFile = file;
+
+ emitBeginSourceStab(file->compileUnit);
+ emitObjectFileStab(file);
+ }
+ emitFunStabs(defined);
+ }
+ // TODO emit stabs for non-function symbols too
+ }
}
+
+ if (!stabs.empty())
+ emitEndSourceStab();
}
void SymtabSection::writeTo(uint8_t *buf) const {
@@ -602,12 +687,23 @@ void SymtabSection::writeTo(uint8_t *buf) const {
nList->n_type = MachO::N_EXT | MachO::N_SECT;
nList->n_sect = defined->isec->parent->index;
// For the N_SECT symbol type, n_value is the address of the symbol
- nList->n_value = defined->value + defined->isec->getVA();
+ nList->n_value = defined->getVA();
}
nList->n_desc |= defined->isWeakDef() ? MachO::N_WEAK_DEF : 0;
}
++nList;
}
+
+ // Emit the stabs entries after the "real" symbols. We cannot emit them
+ // before as that would render Symbol::symtabIndex inaccurate.
+ for (const StabsEntry &entry : stabs) {
+ nList->n_strx = entry.strx;
+ nList->n_type = entry.type;
+ nList->n_sect = entry.sect;
+ nList->n_desc = entry.desc;
+ nList->n_value = entry.value;
+ ++nList;
+ }
}
IndirectSymtabSection::IndirectSymtabSection()
@@ -656,7 +752,7 @@ StringTableSection::StringTableSection()
uint32_t StringTableSection::addString(StringRef str) {
uint32_t strx = size;
- strings.push_back(str);
+ strings.push_back(str); // TODO: consider deduplicating strings
size += str.size() + 1; // account for null terminator
return strx;
}
diff --git a/lld/MachO/SyntheticSections.h b/lld/MachO/SyntheticSections.h
index 1736b6a900ca..4a8820a285a8 100644
--- a/lld/MachO/SyntheticSections.h
+++ b/lld/MachO/SyntheticSections.h
@@ -20,6 +20,10 @@
#include "llvm/ADT/SetVector.h"
#include "llvm/Support/raw_ostream.h"
+namespace llvm {
+class DWARFUnit;
+} // namespace llvm
+
namespace lld {
namespace macho {
@@ -48,6 +52,7 @@ constexpr const char ehFrame[] = "__eh_frame";
class Defined;
class DylibSymbol;
class LoadCommand;
+class ObjFile;
class SyntheticSection : public OutputSection {
public:
@@ -405,16 +410,32 @@ struct SymtabEntry {
size_t strx;
};
+struct StabsEntry {
+ uint8_t type;
+ uint32_t strx = 0;
+ uint8_t sect = 0;
+ uint16_t desc = 0;
+ uint64_t value = 0;
+
+ explicit StabsEntry(uint8_t type) : type(type) {}
+};
+
class SymtabSection : public LinkEditSection {
public:
SymtabSection(StringTableSection &);
void finalizeContents();
- size_t getNumSymbols() const { return symbols.size(); }
+ size_t getNumSymbols() const { return stabs.size() + symbols.size(); }
uint64_t getRawSize() const override;
void writeTo(uint8_t *buf) const override;
private:
+ void emitBeginSourceStab(llvm::DWARFUnit *compileUnit);
+ void emitEndSourceStab();
+ void emitObjectFileStab(ObjFile *);
+ void emitFunStabs(Defined *);
+
StringTableSection &stringTableSection;
+ std::vector<StabsEntry> stabs;
std::vector<SymtabEntry> symbols;
};
diff --git a/lld/MachO/Writer.cpp b/lld/MachO/Writer.cpp
index fa42c1c7e61c..e9d88af90ecc 100644
--- a/lld/MachO/Writer.cpp
+++ b/lld/MachO/Writer.cpp
@@ -578,6 +578,10 @@ void Writer::createOutputSections() {
MapVector<std::pair<StringRef, StringRef>, MergedOutputSection *>
mergedOutputSections;
for (InputSection *isec : inputSections) {
+ // Instead of emitting DWARF sections, we emit STABS symbols to the object
+ // files that contain them.
+ if (isDebugSection(isec->flags) && isec->segname == segment_names::dwarf)
+ continue;
MergedOutputSection *&osec =
mergedOutputSections[{isec->segname, isec->name}];
if (osec == nullptr)
@@ -591,8 +595,9 @@ void Writer::createOutputSections() {
if (unwindInfoSection && segname == segment_names::ld) {
assert(osec->name == section_names::compactUnwind);
unwindInfoSection->setCompactUnwindSection(osec);
- } else
+ } else {
getOrCreateOutputSegment(segname)->addOutputSection(osec);
+ }
}
for (SyntheticSection *ssec : syntheticSections) {
diff --git a/lld/test/MachO/stabs.s b/lld/test/MachO/stabs.s
new file mode 100644
index 000000000000..5e85ccc3bc4a
--- /dev/null
+++ b/lld/test/MachO/stabs.s
@@ -0,0 +1,114 @@
+# REQUIRES: x86
+# UNSUPPORTED: system-windows
+# RUN: split-file %s %t
+# RUN: llvm-mc -filetype=obj -triple=x86_64-apple-darwin %t/test.s -o %t/test.o
+# RUN: llvm-mc -filetype=obj -triple=x86_64-apple-darwin %t/foo.s -o %t/foo.o
+
+# RUN: %lld -lSystem %t/test.o %t/foo.o -o %t/test
+# RUN: llvm-nm -pa %t/test | FileCheck %s -DDIR=%t
+
+## Check that we emit absolute paths to the object files in our OSO entries
+## even if our inputs are relative paths.
+# RUN: cd %t && %lld -lSystem test.o foo.o -o test
+# RUN: llvm-nm -pa %t/test | FileCheck %s -DDIR=%t
+
+# CHECK-DAG: [[#%x, MAIN:]] T _main
+# CHECK-DAG: [[#%x, FOO: ]] T _foo
+# CHECK: 0000000000000000 - 00 0000 SO /tmp/test.cpp
+# CHECK-NEXT: 0000000000000000 - 03 0001 OSO [[DIR]]/test.o
+# CHECK-NEXT: [[#MAIN]] - 01 0000 FUN _main
+# CHECK-NEXT: 0000000000000001 - 00 0000 FUN
+# CHECK-NEXT: 0000000000000000 - 01 0000 SO
+# CHECK-NEXT: 0000000000000000 - 00 0000 SO /foo.cpp
+# CHECK-NEXT: 0000000000000000 - 03 0001 OSO [[DIR]]/foo.o
+# CHECK-NEXT: [[#FOO]] - 01 0000 FUN _foo
+# CHECK-NEXT: 0000000000000001 - 00 0000 FUN
+# CHECK-NEXT: 0000000000000000 - 01 0000 SO
+
+#--- test.s
+.text
+.globl _main
+_main:
+Lfunc_begin0:
+ retq
+Lfunc_end0:
+
+.section __DWARF,__debug_str,regular,debug
+ .asciz "test.cpp" ## string offset=0
+ .asciz "/tmp" ## string offset=9
+.section __DWARF,__debug_abbrev,regular,debug
+Lsection_abbrev:
+ .byte 1 ## Abbreviation Code
+ .byte 17 ## DW_TAG_compile_unit
+ .byte 1 ## DW_CHILDREN_yes
+ .byte 3 ## DW_AT_name
+ .byte 14 ## DW_FORM_strp
+ .byte 27 ## DW_AT_comp_dir
+ .byte 14 ## DW_FORM_strp
+ .byte 17 ## DW_AT_low_pc
+ .byte 1 ## DW_FORM_addr
+ .byte 18 ## DW_AT_high_pc
+ .byte 6 ## DW_FORM_data4
+ .byte 0 ## EOM(1)
+.section __DWARF,__debug_info,regular,debug
+.set Lset0, Ldebug_info_end0-Ldebug_info_start0 ## Length of Unit
+ .long Lset0
+Ldebug_info_start0:
+ .short 4 ## DWARF version number
+.set Lset1, Lsection_abbrev-Lsection_abbrev ## Offset Into Abbrev. Section
+ .long Lset1
+ .byte 8 ## Address Size (in bytes)
+ .byte 1 ## Abbrev [1] 0xb:0x48 DW_TAG_compile_unit
+ .long 0 ## DW_AT_name
+ .long 9 ## DW_AT_comp_dir
+ .quad Lfunc_begin0 ## DW_AT_low_pc
+.set Lset3, Lfunc_end0-Lfunc_begin0 ## DW_AT_high_pc
+ .long Lset3
+ .byte 0 ## End Of Children Mark
+Ldebug_info_end0:
+.subsections_via_symbols
+.section __DWARF,__debug_line,regular,debug
+
+#--- foo.s
+.text
+.globl _foo
+_foo:
+Lfunc_begin0:
+ retq
+Lfunc_end0:
+
+.section __DWARF,__debug_str,regular,debug
+ .asciz "foo.cpp" ## string offset=0
+ .asciz "" ## string offset=8
+.section __DWARF,__debug_abbrev,regular,debug
+Lsection_abbrev:
+ .byte 1 ## Abbreviation Code
+ .byte 17 ## DW_TAG_compile_unit
+ .byte 1 ## DW_CHILDREN_yes
+ .byte 3 ## DW_AT_name
+ .byte 14 ## DW_FORM_strp
+ .byte 27 ## DW_AT_comp_dir
+ .byte 14 ## DW_FORM_strp
+ .byte 17 ## DW_AT_low_pc
+ .byte 1 ## DW_FORM_addr
+ .byte 18 ## DW_AT_high_pc
+ .byte 6 ## DW_FORM_data4
+ .byte 0 ## EOM(1)
+.section __DWARF,__debug_info,regular,debug
+.set Lset0, Ldebug_info_end0-Ldebug_info_start0 ## Length of Unit
+ .long Lset0
+Ldebug_info_start0:
+ .short 4 ## DWARF version number
+.set Lset1, Lsection_abbrev-Lsection_abbrev ## Offset Into Abbrev. Section
+ .long Lset1
+ .byte 8 ## Address Size (in bytes)
+ .byte 1 ## Abbrev [1] 0xb:0x48 DW_TAG_compile_unit
+ .long 0 ## DW_AT_name
+ .long 8 ## DW_AT_comp_dir
+ .quad Lfunc_begin0 ## DW_AT_low_pc
+.set Lset3, Lfunc_end0-Lfunc_begin0 ## DW_AT_high_pc
+ .long Lset3
+ .byte 0 ## End Of Children Mark
+Ldebug_info_end0:
+.subsections_via_symbols
+.section __DWARF,__debug_line,regular,debug