[llvm] r239075 - [Object, MachO] Cache parsed MachO header in MachOObjectFile. NFC.
Alexey Samsonov
vonosmas at gmail.com
Thu Jun 4 15:11:59 PDT 2015
On Thu, Jun 4, 2015 at 2:58 PM, David Blaikie <dblaikie at gmail.com> wrote:
>
>
> On Thu, Jun 4, 2015 at 2:37 PM, Rafael Espíndola <
> rafael.espindola at gmail.com> wrote:
>
>> Is asan OK with this? I would assume that a union of
>> MachO::mach_header_64 and MachO::mach_header is necessary.
>>
>
Sanitizers are fine, as we don't do out-of-bounds access or uninitialized
value read. Although I agree that using a union would probably be better...
>
> Perhaps it'd be better to just make mach_header_64 defined:
>
> struct mach_header_64 {
> mach_header m;
> uint32_t reserved;
> };
>
Then we won't be able to access some mach_header_64 fields directly.
> or somesuch - then there's no weird type punning, perhaps? (though maybe
> still invalid if we're trying to point to a 32 bit header from a
> mach_header_64* ?)
>
>
>>
>> Cheers,
>> Rafael
>>
>>
>> On 4 June 2015 at 15:22, Alexey Samsonov <vonosmas at gmail.com> wrote:
>> > Author: samsonov
>> > Date: Thu Jun 4 14:22:03 2015
>> > New Revision: 239075
>> >
>> > URL: http://llvm.org/viewvc/llvm-project?rev=239075&view=rev
>> > Log:
>> > [Object, MachO] Cache parsed MachO header in MachOObjectFile. NFC.
>> >
>> > Summary:
>> > Avoid parsing object file each time MachOObjectFile::getHeader() is
>> > called. Instead, cache the header in MachOObjectFile constructor, where
>> > it's parsed anyway. In future, we must avoid constructing the object
>> > at all if the header can't be parsed.
>> >
>> > Test Plan: regression test suite.
>> >
>> > Reviewers: rafael
>> >
>> > Subscribers: llvm-commits
>> >
>> > Modified:
>> > llvm/trunk/include/llvm/Object/MachO.h
>> > llvm/trunk/lib/Object/MachOObjectFile.cpp
>> >
>> > Modified: llvm/trunk/include/llvm/Object/MachO.h
>> > URL:
>> http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Object/MachO.h?rev=239075&r1=239074&r2=239075&view=diff
>> >
>> ==============================================================================
>> > --- llvm/trunk/include/llvm/Object/MachO.h (original)
>> > +++ llvm/trunk/include/llvm/Object/MachO.h Thu Jun 4 14:22:03 2015
>> > @@ -385,8 +385,8 @@ public:
>> >
>> > MachO::any_relocation_info getRelocation(DataRefImpl Rel) const;
>> > MachO::data_in_code_entry getDice(DataRefImpl Rel) const;
>> > - MachO::mach_header getHeader() const;
>> > - MachO::mach_header_64 getHeader64() const;
>> > + const MachO::mach_header &getHeader() const;
>> > + const MachO::mach_header_64 &getHeader64() const;
>> > uint32_t
>> > getIndirectSymbolTableEntry(const MachO::dysymtab_command &DLC,
>> > unsigned Index) const;
>> > @@ -433,6 +433,7 @@ private:
>> > LoadCommandInfo getFirstLoadCommandInfo() const;
>> > LoadCommandInfo getNextLoadCommandInfo(const LoadCommandInfo &L)
>> const;
>> >
>> > + MachO::mach_header_64 Header64;
>> > typedef SmallVector<const char*, 1> SectionList;
>> > SectionList Sections;
>> > typedef SmallVector<const char*, 1> LibraryList;
>> >
>> > Modified: llvm/trunk/lib/Object/MachOObjectFile.cpp
>> > URL:
>> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Object/MachOObjectFile.cpp?rev=239075&r1=239074&r2=239075&view=diff
>> >
>> ==============================================================================
>> > --- llvm/trunk/lib/Object/MachOObjectFile.cpp (original)
>> > +++ llvm/trunk/lib/Object/MachOObjectFile.cpp Thu Jun 4 14:22:03 2015
>> > @@ -187,7 +187,16 @@ MachOObjectFile::MachOObjectFile(MemoryB
>> > DataInCodeLoadCmd(nullptr), LinkOptHintsLoadCmd(nullptr),
>> > DyldInfoLoadCmd(nullptr), UuidLoadCmd(nullptr),
>> > HasPageZeroSegment(false) {
>> > - uint32_t LoadCommandCount = this->getHeader().ncmds;
>> > + // Parse header.
>> > + if (is64Bit())
>> > + Header64 = getStruct<MachO::mach_header_64>(this, getPtr(this, 0));
>> > + else
>> > + // First fields of MachO::mach_header_64 are the same as
>> > + // in MachO::mach_header.
>> > + *reinterpret_cast<MachO::mach_header *>(&this->Header64) =
>> > + getStruct<MachO::mach_header>(this, getPtr(this, 0));
>> > +
>> > + uint32_t LoadCommandCount = getHeader().ncmds;
>> > if (LoadCommandCount == 0)
>> > return;
>> >
>> > @@ -1195,21 +1204,9 @@ unsigned MachOObjectFile::getArch() cons
>> >
>> > Triple MachOObjectFile::getArch(const char **McpuDefault,
>> > Triple *ThumbTriple) const {
>> > - Triple T;
>> > - if (is64Bit()) {
>> > - MachO::mach_header_64 H_64;
>> > - H_64 = getHeader64();
>> > - T = MachOObjectFile::getArch(H_64.cputype, H_64.cpusubtype,
>> McpuDefault);
>> > - *ThumbTriple = MachOObjectFile::getThumbArch(H_64.cputype,
>> H_64.cpusubtype,
>> > - McpuDefault);
>> > - } else {
>> > - MachO::mach_header H;
>> > - H = getHeader();
>> > - T = MachOObjectFile::getArch(H.cputype, H.cpusubtype, McpuDefault);
>> > - *ThumbTriple = MachOObjectFile::getThumbArch(H.cputype,
>> H.cpusubtype,
>> > - McpuDefault);
>> > - }
>> > - return T;
>> > + const auto &Header = getHeader();
>> > + *ThumbTriple = getThumbArch(Header.cputype, Header.cpusubtype,
>> McpuDefault);
>> > + return getArch(Header.cputype, Header.cpusubtype, McpuDefault);
>> > }
>> >
>> > relocation_iterator MachOObjectFile::section_rel_begin(unsigned Index)
>> const {
>> > @@ -2164,12 +2161,15 @@ MachOObjectFile::getDice(DataRefImpl Rel
>> > return getStruct<MachO::data_in_code_entry>(this, P);
>> > }
>> >
>> > -MachO::mach_header MachOObjectFile::getHeader() const {
>> > - return getStruct<MachO::mach_header>(this, getPtr(this, 0));
>> > +const MachO::mach_header &MachOObjectFile::getHeader() const {
>> > + // First fields of MachO::mach_header_64 are the same as
>> > + // in MachO::mach_header.
>> > + return *reinterpret_cast<const MachO::mach_header
>> *>(&this->Header64);
>> > }
>> >
>> > -MachO::mach_header_64 MachOObjectFile::getHeader64() const {
>> > - return getStruct<MachO::mach_header_64>(this, getPtr(this, 0));
>> > +const MachO::mach_header_64 &MachOObjectFile::getHeader64() const {
>> > + assert(is64Bit());
>> > + return Header64;
>> > }
>> >
>> > uint32_t MachOObjectFile::getIndirectSymbolTableEntry(
>> >
>> >
>> > _______________________________________________
>> > llvm-commits mailing list
>> > llvm-commits at cs.uiuc.edu
>> > http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits
>> _______________________________________________
>> llvm-commits mailing list
>> llvm-commits at cs.uiuc.edu
>> http://lists.cs.uiuc.edu/mailman/listinfo/llvm-commits
>>
>
>
--
Alexey Samsonov
vonosmas at gmail.com
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.llvm.org/pipermail/llvm-commits/attachments/20150604/cf210c96/attachment.html>
More information about the llvm-commits
mailing list