[llvm] r254355 - [llvm-dwp] Initial partial prototype
Xinliang David Li via llvm-commits
llvm-commits at lists.llvm.org
Mon Nov 30 23:03:48 PST 2015
Note that file local static variable initialization can add non trivial
runtime overhead of a guard variable read for each execution of the scope
in which the static variable is defined (in the loop of this case). It can
also bloat the code size a lot due to calls to __cxa_guard_acquire|lrelease
etc.
David
On Mon, Nov 30, 2015 at 8:56 PM, David Blaikie via llvm-commits <
llvm-commits at lists.llvm.org> wrote:
>
>
> On Mon, Nov 30, 2015 at 8:26 PM, Sean Silva <chisophugis at gmail.com> wrote:
>
>>
>>
>> On Mon, Nov 30, 2015 at 4:48 PM, David Blaikie via llvm-commits <
>> llvm-commits at lists.llvm.org> wrote:
>>
>>> Author: dblaikie
>>> Date: Mon Nov 30 18:48:39 2015
>>> New Revision: 254355
>>>
>>> URL: http://llvm.org/viewvc/llvm-project?rev=254355&view=rev
>>> Log:
>>> [llvm-dwp] Initial partial prototype
>>>
>>> This just concatenates the common DWP sections without doing any of the
>>> fancy DWP things like:
>>>
>>> 1) update str_offsets
>>> 2) deduplicating strings
>>> 3) merging/creating cu/tu_index
>>>
>>> Patches for these will follow shortly.
>>>
>>> (also not sure about target triple/object file type for this tool - do I
>>> really need a whole triple just to write an object file that contains
>>> purely static/hardcoded bytes in each section? & I guess I should just
>>> pick it based on the first input, maybe, rather than hardcoding for now
>>> - but we only produce .dwo on ELF platforms with objcopy for now anyway)
>>>
>>> Added:
>>> llvm/trunk/test/tools/llvm-dwp/
>>> llvm/trunk/test/tools/llvm-dwp/Inputs/
>>> llvm/trunk/test/tools/llvm-dwp/Inputs/simple/
>>> llvm/trunk/test/tools/llvm-dwp/Inputs/simple/a.cpp
>>> llvm/trunk/test/tools/llvm-dwp/Inputs/simple/a.dwo
>>> llvm/trunk/test/tools/llvm-dwp/Inputs/simple/b.cpp
>>> llvm/trunk/test/tools/llvm-dwp/Inputs/simple/b.dwo
>>> llvm/trunk/test/tools/llvm-dwp/X86/
>>> llvm/trunk/test/tools/llvm-dwp/X86/lit.local.cfg
>>> llvm/trunk/test/tools/llvm-dwp/X86/simple.test
>>> Modified:
>>> llvm/trunk/include/llvm/ADT/StringMap.h
>>> llvm/trunk/include/llvm/ADT/StringSet.h
>>> llvm/trunk/tools/llvm-dwp/llvm-dwp.cpp
>>>
>>> Modified: llvm/trunk/include/llvm/ADT/StringMap.h
>>> URL:
>>> http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/ADT/StringMap.h?rev=254355&r1=254354&r2=254355&view=diff
>>>
>>> ==============================================================================
>>> --- llvm/trunk/include/llvm/ADT/StringMap.h (original)
>>> +++ llvm/trunk/include/llvm/ADT/StringMap.h Mon Nov 30 18:48:39 2015
>>> @@ -232,6 +232,13 @@ public:
>>> : StringMapImpl(InitialSize,
>>> static_cast<unsigned>(sizeof(MapEntryTy))),
>>> Allocator(A) {}
>>>
>>> + StringMap(std::initializer_list<std::pair<StringRef, ValueTy>> List)
>>> + : StringMapImpl(static_cast<unsigned>(sizeof(MapEntryTy))) {
>>> + for (const auto &P : List) {
>>> + insert(P);
>>> + }
>>> + }
>>> +
>>> StringMap(StringMap &&RHS)
>>> : StringMapImpl(std::move(RHS)),
>>> Allocator(std::move(RHS.Allocator)) {}
>>>
>>>
>>> Modified: llvm/trunk/include/llvm/ADT/StringSet.h
>>> URL:
>>> http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/ADT/StringSet.h?rev=254355&r1=254354&r2=254355&view=diff
>>>
>>> ==============================================================================
>>> --- llvm/trunk/include/llvm/ADT/StringSet.h (original)
>>> +++ llvm/trunk/include/llvm/ADT/StringSet.h Mon Nov 30 18:48:39 2015
>>> @@ -23,6 +23,11 @@ namespace llvm {
>>> class StringSet : public llvm::StringMap<char, AllocatorTy> {
>>> typedef llvm::StringMap<char, AllocatorTy> base;
>>> public:
>>> + StringSet() = default;
>>> + StringSet(std::initializer_list<StringRef> S) {
>>> + for (StringRef X : S)
>>> + insert(X);
>>> + }
>>>
>>> std::pair<typename base::iterator, bool> insert(StringRef Key) {
>>> assert(!Key.empty());
>>>
>>> Added: llvm/trunk/test/tools/llvm-dwp/Inputs/simple/a.cpp
>>> URL:
>>> http://llvm.org/viewvc/llvm-project/llvm/trunk/test/tools/llvm-dwp/Inputs/simple/a.cpp?rev=254355&view=auto
>>>
>>> ==============================================================================
>>> --- llvm/trunk/test/tools/llvm-dwp/Inputs/simple/a.cpp (added)
>>> +++ llvm/trunk/test/tools/llvm-dwp/Inputs/simple/a.cpp Mon Nov 30
>>> 18:48:39 2015
>>> @@ -0,0 +1,2 @@
>>> +struct foo { };
>>> +foo a;
>>>
>>> Added: llvm/trunk/test/tools/llvm-dwp/Inputs/simple/a.dwo
>>> URL:
>>> http://llvm.org/viewvc/llvm-project/llvm/trunk/test/tools/llvm-dwp/Inputs/simple/a.dwo?rev=254355&view=auto
>>>
>>> ==============================================================================
>>> Binary files llvm/trunk/test/tools/llvm-dwp/Inputs/simple/a.dwo (added)
>>> and llvm/trunk/test/tools/llvm-dwp/Inputs/simple/a.dwo Mon Nov 30 18:48:39
>>> 2015 differ
>>>
>>> Added: llvm/trunk/test/tools/llvm-dwp/Inputs/simple/b.cpp
>>> URL:
>>> http://llvm.org/viewvc/llvm-project/llvm/trunk/test/tools/llvm-dwp/Inputs/simple/b.cpp?rev=254355&view=auto
>>>
>>> ==============================================================================
>>> --- llvm/trunk/test/tools/llvm-dwp/Inputs/simple/b.cpp (added)
>>> +++ llvm/trunk/test/tools/llvm-dwp/Inputs/simple/b.cpp Mon Nov 30
>>> 18:48:39 2015
>>> @@ -0,0 +1,3 @@
>>> +struct bar { };
>>> +void b(bar) {
>>> +}
>>>
>>> Added: llvm/trunk/test/tools/llvm-dwp/Inputs/simple/b.dwo
>>> URL:
>>> http://llvm.org/viewvc/llvm-project/llvm/trunk/test/tools/llvm-dwp/Inputs/simple/b.dwo?rev=254355&view=auto
>>>
>>> ==============================================================================
>>> Binary files llvm/trunk/test/tools/llvm-dwp/Inputs/simple/b.dwo (added)
>>> and llvm/trunk/test/tools/llvm-dwp/Inputs/simple/b.dwo Mon Nov 30 18:48:39
>>> 2015 differ
>>>
>>> Added: llvm/trunk/test/tools/llvm-dwp/X86/lit.local.cfg
>>> URL:
>>> http://llvm.org/viewvc/llvm-project/llvm/trunk/test/tools/llvm-dwp/X86/lit.local.cfg?rev=254355&view=auto
>>>
>>> ==============================================================================
>>> --- llvm/trunk/test/tools/llvm-dwp/X86/lit.local.cfg (added)
>>> +++ llvm/trunk/test/tools/llvm-dwp/X86/lit.local.cfg Mon Nov 30 18:48:39
>>> 2015
>>> @@ -0,0 +1,4 @@
>>> +if not 'X86' in config.root.targets:
>>> + config.unsupported = True
>>> +
>>> +config.suffixes = ['.test', '.cpp', '.m', '.s']
>>>
>>> Added: llvm/trunk/test/tools/llvm-dwp/X86/simple.test
>>> URL:
>>> http://llvm.org/viewvc/llvm-project/llvm/trunk/test/tools/llvm-dwp/X86/simple.test?rev=254355&view=auto
>>>
>>> ==============================================================================
>>> --- llvm/trunk/test/tools/llvm-dwp/X86/simple.test (added)
>>> +++ llvm/trunk/test/tools/llvm-dwp/X86/simple.test Mon Nov 30 18:48:39
>>> 2015
>>> @@ -0,0 +1,58 @@
>>> +RUN: llvm-dwp %p/../Inputs/simple/a.dwo %p/../Inputs/simple/b.dwo -o %t
>>> +RUN: llvm-dwarfdump %t | FileCheck %s
>>> +
>>> +FIXME: For some reason, piping straight from llvm-dwp to llvm-dwarfdump
>>> doesn't behave well - looks like dwarfdump is reading/closes before dwp has
>>> finished.
>>> +
>>> +DWP from non-type-unit debug info for these two translation units:
>>> +a.cpp:
>>> + struct foo { };
>>> + foo a;
>>> +
>>> +b.cpp:
>>> + struct bar { };
>>> + void b(bar) {
>>> + }
>>> +
>>> +CHECK: .debug_abbrev.dwo contents:
>>> +CHECK: Abbrev table for offset: 0x00000000
>>> +CHECK: DW_TAG_compile_unit
>>> +CHECK: DW_TAG_variable
>>> +CHECK: DW_TAG_structure_type
>>> +CHECK: Abbrev table for offset: 0x00000031
>>> +CHECK: DW_TAG_compile_unit
>>> +CHECK: DW_TAG_structure_type
>>> +CHECK: DW_TAG_subprogram
>>> +CHECK: DW_TAG_formal_parameter
>>> +
>>> +CHECK: .debug_info.dwo contents:
>>> +CHECK: 0x00000000: Compile Unit: length = 0x00000025 version = 0x0004
>>> abbr_offset = 0x0000 addr_size = 0x08 (next unit at 0x00000029)
>>> +CHECK: DW_TAG_compile_unit
>>> +CHECK: DW_AT_name {{.*}} "a.cpp"
>>> +CHECK: DW_TAG_variable
>>> +CHECK: DW_AT_name {{.*}} "a"
>>> +CHECK: DW_TAG_structure_type
>>> +CHECK: DW_AT_name {{.*}} "foo"
>>> +
>>> +FIXME: Using cu_index, identify that abbr_offset is 0x0031, not 0x0000
>>> +CHECK: 0x00000029: Compile Unit: length = 0x00000031 version = 0x0004
>>> abbr_offset = 0x0000 addr_size = 0x08 (next unit at 0x0000005e)
>>> +FIXME: Using cu_index, use strings based on the right str index offset
>>> +CHECK: DW_AT_name {{.*}} "a.cpp"
>>> +FIXME: Using cu_index to find the right abbrevs at abbr_offset, this
>>> abbrevation should actually be structure_type
>>> +CHECK: DW_TAG_variable
>>> +
>>> +CHECK: .debug_cu_index contents:
>>> +FIXME: Emit and verify the cu_index contents
>>> +
>>> +CHECK: .debug_str.dwo contents:
>>> +CHECK: "clang version
>>> +CHECK: 0x[[ACPP:.*]]: "a.cpp"
>>> +FIXME: Remove duplicates
>>> +CHECK: "clang version
>>> +CHECK: 0x[[BCPP:.*]]: "b.cpp"
>>> +
>>> +CHECK: .debug_str_offsets.dwo contents:
>>> +CHECK: : 00000000
>>> +CHECK: : [[ACPP]]
>>> +CHECK: : 00000000
>>> +FIXME: Update str offset indexes, this should be BCPP \/
>>> +CHECK: : [[ACPP]]
>>>
>>> Modified: llvm/trunk/tools/llvm-dwp/llvm-dwp.cpp
>>> URL:
>>> http://llvm.org/viewvc/llvm-project/llvm/trunk/tools/llvm-dwp/llvm-dwp.cpp?rev=254355&r1=254354&r2=254355&view=diff
>>>
>>> ==============================================================================
>>> --- llvm/trunk/tools/llvm-dwp/llvm-dwp.cpp (original)
>>> +++ llvm/trunk/tools/llvm-dwp/llvm-dwp.cpp Mon Nov 30 18:48:39 2015
>>> @@ -1,2 +1,144 @@
>>> -int main() {
>>> +#include "llvm/ADT/STLExtras.h"
>>> +#include "llvm/ADT/StringSet.h"
>>> +#include "llvm/CodeGen/AsmPrinter.h"
>>> +#include "llvm/MC/MCAsmInfo.h"
>>> +#include "llvm/MC/MCContext.h"
>>> +#include "llvm/MC/MCInstrInfo.h"
>>> +#include "llvm/MC/MCObjectFileInfo.h"
>>> +#include "llvm/MC/MCRegisterInfo.h"
>>> +#include "llvm/MC/MCSectionELF.h"
>>> +#include "llvm/MC/MCStreamer.h"
>>> +#include "llvm/Object/ObjectFile.h"
>>> +#include "llvm/Support/Options.h"
>>> +#include "llvm/Support/FileSystem.h"
>>> +#include "llvm/Support/MemoryBuffer.h"
>>> +#include "llvm/Support/TargetRegistry.h"
>>> +#include "llvm/Support/raw_ostream.h"
>>> +#include "llvm/Target/TargetMachine.h"
>>> +#include "llvm/Support/TargetSelect.h"
>>> +#include <memory>
>>> +#include <list>
>>> +#include <unordered_set>
>>> +
>>> +using namespace llvm;
>>> +using namespace cl;
>>> +
>>> +OptionCategory DwpCategory("Specific Options");
>>> +static list<std::string> InputFiles(Positional, OneOrMore,
>>> + desc("<input files>"),
>>> cat(DwpCategory));
>>> +
>>> +static opt<std::string> OutputFilename(Required, "o", desc("Specify the
>>> output file."),
>>> + value_desc("filename"),
>>> cat(DwpCategory));
>>> +
>>> +static int error(const Twine &Error, const Twine &Context) {
>>> + errs() << Twine("while processing ") + Context + ":\n";
>>> + errs() << Twine("error: ") + Error + "\n";
>>> + return 1;
>>> +}
>>> +
>>> +static std::error_code writeSection(MCStreamer &Out, MCSection
>>> *OutSection,
>>> + const object::SectionRef &Sym) {
>>> + StringRef Contents;
>>> + if (auto Err = Sym.getContents(Contents))
>>> + return Err;
>>> + Out.SwitchSection(OutSection);
>>> + Out.EmitBytes(Contents);
>>> + return std::error_code();
>>> +}
>>> +
>>> +static std::error_code write(MCStreamer &Out, ArrayRef<std::string>
>>> Inputs) {
>>> + for (const auto &Input : Inputs) {
>>> + auto ErrOrObj = object::ObjectFile::createObjectFile(Input);
>>> + if (!ErrOrObj)
>>> + return ErrOrObj.getError();
>>> + const auto *Obj = ErrOrObj->getBinary();
>>> + for (const auto &Section : Obj->sections()) {
>>> + const auto &MCOFI = *Out.getContext().getObjectFileInfo();
>>> + static const StringMap<MCSection *> KnownSections = {
>>> + {"debug_info.dwo", MCOFI.getDwarfInfoDWOSection()},
>>> + {"debug_types.dwo", MCOFI.getDwarfTypesDWOSection()},
>>> + {"debug_str_offsets.dwo", MCOFI.getDwarfStrOffDWOSection()},
>>> + {"debug_str.dwo", MCOFI.getDwarfStrDWOSection()},
>>> + {"debug_loc.dwo", MCOFI.getDwarfLocDWOSection()},
>>> + {"debug_abbrev.dwo", MCOFI.getDwarfAbbrevDWOSection()}};
>>>
>>
>> How can this be `static` when it depends on a local variable? I'm
>> actually somewhat surprised it compiles.
>>
>
> Static variables are initialized the first time control passes through
> them - they can use any state (global, local, etc) like a non-static local
> variable would.
>
> Though, as it turns out, I'm moving away from that design (while it
> doesn't need to be more general, it is a bit hokey that if you called this
> twice (if, for some reason, your DWP tool was designed to emit more than
> one DWP file) it would not work) - just moved the map to the top level of
> this function and made it non-static. It's equivalent here/for this use and
> doesn't have weird "only works the first call" behavior.
>
> My next patch, which is adding str/str_index support will have that
> refactored away to remove the static here.
>
> - Dave
>
>
>>
>> -- Sean Silva
>>
>>
>>> + StringRef Name;
>>> + if (std::error_code Err = Section.getName(Name))
>>> + return Err;
>>> + if (MCSection *OutSection =
>>> +
>>> KnownSections.lookup(Name.substr(Name.find_first_not_of("._"))))
>>> + if (auto Err = writeSection(Out, OutSection, Section))
>>> + return Err;
>>> + }
>>> + }
>>> + return std::error_code();
>>> +}
>>> +
>>> +int main(int argc, char** argv) {
>>> +
>>> + ParseCommandLineOptions(argc, argv, "merge split dwarf (.dwo) files");
>>> +
>>> + llvm::InitializeAllTargetInfos();
>>> + llvm::InitializeAllTargetMCs();
>>> + llvm::InitializeAllTargets();
>>> + llvm::InitializeAllAsmPrinters();
>>> +
>>> + std::string ErrorStr;
>>> + StringRef Context = "dwarf streamer init";
>>> +
>>> + Triple TheTriple("x86_64-linux-gnu");
>>> +
>>> + // Get the target.
>>> + const Target *TheTarget =
>>> + TargetRegistry::lookupTarget("", TheTriple, ErrorStr);
>>> + if (!TheTarget)
>>> + return error(ErrorStr, Context);
>>> + std::string TripleName = TheTriple.getTriple();
>>> +
>>> + // Create all the MC Objects.
>>> + std::unique_ptr<MCRegisterInfo>
>>> MRI(TheTarget->createMCRegInfo(TripleName));
>>> + if (!MRI)
>>> + return error(Twine("no register info for target ") + TripleName,
>>> Context);
>>> +
>>> + std::unique_ptr<MCAsmInfo> MAI(TheTarget->createMCAsmInfo(*MRI,
>>> TripleName));
>>> + if (!MAI)
>>> + return error("no asm info for target " + TripleName, Context);
>>> +
>>> + MCObjectFileInfo MOFI;
>>> + MCContext MC(MAI.get(), MRI.get(), &MOFI);
>>> + MOFI.InitMCObjectFileInfo(TheTriple, Reloc::Default,
>>> CodeModel::Default,
>>> + MC);
>>> +
>>> + auto MAB = TheTarget->createMCAsmBackend(*MRI, TripleName, "");
>>> + if (!MAB)
>>> + return error("no asm backend for target " + TripleName, Context);
>>> +
>>> + std::unique_ptr<MCInstrInfo> MII(TheTarget->createMCInstrInfo());
>>> + if (!MII)
>>> + return error("no instr info info for target " + TripleName,
>>> Context);
>>> +
>>> + std::unique_ptr<MCSubtargetInfo> MSTI(
>>> + TheTarget->createMCSubtargetInfo(TripleName, "", ""));
>>> + if (!MSTI)
>>> + return error("no subtarget info for target " + TripleName, Context);
>>> +
>>> + MCCodeEmitter *MCE = TheTarget->createMCCodeEmitter(*MII, *MRI, MC);
>>> + if (!MCE)
>>> + return error("no code emitter for target " + TripleName, Context);
>>> +
>>> + // Create the output file.
>>> + std::error_code EC;
>>> + raw_fd_ostream OutFile(OutputFilename, EC, sys::fs::F_None);
>>> + if (EC)
>>> + return error(Twine(OutputFilename) + ": " + EC.message(), Context);
>>> +
>>> + std::unique_ptr<MCStreamer> MS(TheTarget->createMCObjectStreamer(
>>> + TheTriple, MC, *MAB, OutFile, MCE, *MSTI, false,
>>> + /*DWARFMustBeAtTheEnd*/ false));
>>> + if (!MS)
>>> + return error("no object streamer for target " + TripleName,
>>> Context);
>>> +
>>> + if (auto Err = write(*MS, InputFiles))
>>> + return error(Err.message(), "Writing DWP file");
>>> +
>>> + MS->Finish();
>>> }
>>>
>>>
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>>>
>>
>>
>
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