method instead.
This is not quite a named constructor: Construction may fail, and
MachOObjectFiles are usually passed by unique_ptr anyway, so create
returns an Expected<std::unique_ptr<MachOObjectFile>>.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@264469 91177308-0d34-0410-b5e6-96231b3b80d8
in the test suite. While this is not really an interesting tool and option to run
on a Mach-O file to show the symbol table in a generic libObject format
it shouldn’t crash.
The reason for the crash was in MachOObjectFile::getSymbolType() when it was
calling MachOObjectFile::getSymbolSection() without checking its return value
for the error case.
What makes this fix require a fair bit of diffs is that the method getSymbolType() is
in the class ObjectFile defined without an ErrorOr<> so I needed to add that all
the sub classes. And all of the uses needed to be updated and the return value
needed to be checked for the error case.
The MachOObjectFile version of getSymbolType() “can” get an error in trying to
come up with the libObject’s internal SymbolRef::Type when the Mach-O symbol
symbol type is an N_SECT type because the code is trying to select from the
SymbolRef::ST_Data or SymbolRef::ST_Function values for the SymbolRef::Type.
And it needs the Mach-O section to use isData() and isBSS to determine if
it will return SymbolRef::ST_Data.
One other possible fix I considered is to simply return SymbolRef::ST_Other
when MachOObjectFile::getSymbolSection() returned an error. But since in
the past when I did such changes that “ate an error in the libObject code” I
was asked instead to push the error out of the libObject code I chose not
to implement the fix this way.
As currently written both the COFF and ELF versions of getSymbolType()
can’t get an error. But if isReservedSectionNumber() wanted to check for
the two known negative values rather than allowing all negative values or
the code wanted to add the same check as in getSymbolAddress() to use
getSection() and check for the error then these versions of getSymbolType()
could return errors.
At the end of the day the error printed now is the generic “Invalid data was
encountered while parsing the file” for object_error::parse_failed. In the
future when we thread Lang’s new TypedError for recoverable error handling
though libObject this will improve. And where the added // Diagnostic(…
comment is, it would be changed to produce and error message
like “bad section index (42) for symbol at index 8” for this case.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@264187 91177308-0d34-0410-b5e6-96231b3b80d8
in MachOObjectFile::getSymbolByIndex() when a Mach-O file has
a symbol table load command but the number of symbols are zero.
The code in MachOObjectFile::symbol_begin_impl() should not be
assuming there is a symbol at index 0, in cases there is no symbol
table load command or the count of symbol is zero. So I also fixed
that. And needed to fix MachOObjectFile::symbol_end_impl() to
also do the same thing for no symbol table or one with zero entries.
The code in MachOObjectFile::getSymbolByIndex() should trigger
the report_fatal_error() for programmatic errors for any index when
there is no symbol table load command and not return the end iterator.
So also fixed that. Note there is no test case as this is a programmatic
error.
The test case using the file macho-invalid-bad-symbol-index has
a symbol table load command with its number of symbols (nsyms)
is zero. Which was incorrectly testing the bad triggering of the
report_fatal_error() in in MachOObjectFile::getSymbolByIndex().
This test case is an invalid Mach-O file but not for that reason.
It appears this Mach-O file use to have an nsyms value of 11,
and what makes this Mach-O file invalid is the counts and
indexes into the symbol table of the dynamic load command
are now invalid because the number of symbol table entries
(nsyms) is now zero. Which can be seen with the existing
llvm-obdump:
% llvm-objdump -private-headers macho-invalid-bad-symbol-index
…
Load command 4
cmd LC_SYMTAB
cmdsize 24
symoff 4216
nsyms 0
stroff 4392
strsize 144
Load command 5
cmd LC_DYSYMTAB
cmdsize 80
ilocalsym 0
nlocalsym 8 (past the end of the symbol table)
iextdefsym 8 (greater than the number of symbols)
nextdefsym 2 (past the end of the symbol table)
iundefsym 10 (greater than the number of symbols)
nundefsym 1 (past the end of the symbol table)
...
And the native darwin tools generates an error for this file:
% nm macho-invalid-bad-symbol-index
nm: object: macho-invalid-bad-symbol-index truncated or malformed object (ilocalsym plus nlocalsym in LC_DYSYMTAB load command extends past the end of the symbol table)
I added new checks for the indexes and sizes for these in the
constructor of MachOObjectFile. And added comments for what
would be a proper diagnostic messages.
And changed the test case using macho-invalid-bad-symbol-index
to test for the new error now produced.
Also added a test with a valid Mach-O file with a symbol table
load command where the number of symbols is zero that shows
the report_fatal_error() is not called.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@258576 91177308-0d34-0410-b5e6-96231b3b80d8
but to return object_error::parse_failed. Then made the code in llvm-nm
do for Mach-O files what is done in the darwin native tools which is to
print "bad string index" for bad string indexes. Updated the error message
in the llvm-objdump test, and added tests to show llvm-nm prints
"bad string index" and a test to print the actual bad string index value
which in this case is 0xfe000002 when printing the fields as raw hex.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@258520 91177308-0d34-0410-b5e6-96231b3b80d8
but to return object_error::parse_failed. Then made the code in llvm-nm
do for Mach-O files what is done in the darwin native tools which is to
print "(?,?)" or just "s" for bad section indexes. Also added a test to show
it prints the bad section index of "42" when printing the fields as raw hex.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@258434 91177308-0d34-0410-b5e6-96231b3b80d8
In `MachOObjectFile::getSymbolType` we currently always return `SymbolRef::ST_Function` for symbols from any section. In order for llvm-symbolizer to correctly symbolize Mach-O globals, symbols from data and BSS sections should return `SymbolRef::ST_Data`.
Differential Revision: http://reviews.llvm.org/D14576
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@252867 91177308-0d34-0410-b5e6-96231b3b80d8
from malformed Mach-O files that caused a crash because of a
section header had a size that extended past the end of the file.
rdar://22983603
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@249768 91177308-0d34-0410-b5e6-96231b3b80d8
While introducing support for MinVersionLoadCommand in llvm-readobj I noticed there's
no API to extract Major/Minor/Update components conveniently. Currently consumers
do the bit twiddling on their own, but this will change from now on.
I'll convert llvm-objdump (and llvm-readobj) in a later commit.
Differential Revision: http://reviews.llvm.org/D12282
Reviewed by: rafael
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@245938 91177308-0d34-0410-b5e6-96231b3b80d8
This function can actually fail since the symbol contains an index to the
section and that can be invalid.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@244375 91177308-0d34-0410-b5e6-96231b3b80d8
getSymbolValue now returns a value that in convenient for most callers:
* 0 for undefined
* symbol size for common symbols
* offset/address for symbols the rest
Code that needs something more specific can check getSymbolFlags.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@241605 91177308-0d34-0410-b5e6-96231b3b80d8
At least not in the interface exposed by ObjectFile. This matches what ELF and
COFF implement.
Adjust existing code that was expecting them to have values. No overall
functionality change intended.
Another option would be to change the interface and the ELF and COFF
implementations to say that the value of a common symbol is its size.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@241593 91177308-0d34-0410-b5e6-96231b3b80d8
They are implemented like that in some object formats, but for the interface
provided by lib/Object, SF_Undefined and SF_Common are different things.
This matches the ELF and COFF implementation and fixes llvm-nm for MachO.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@241587 91177308-0d34-0410-b5e6-96231b3b80d8
In these two contexts we really just want the raw n_value. No need to use
getSymbolValue which checks for special cases where, semantically, the symbol
has no value.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@241584 91177308-0d34-0410-b5e6-96231b3b80d8
Originally added in r139314.
Back then it didn't actually get the address, it got whatever value the
relocation used: address or offset.
The values in different object formats are:
* MachO: Always an offset.
* COFF: Always an address, but when talking about the virtual address of
sections it says: "for simplicity, compilers should set this to zero".
* ELF: An offset for .o files and and address for .so files. In the case of the
.so, the relocation in not linked to any section (sh_info is 0). We can't
really compute an offset.
Some API mappings would be:
* Use getAddress for everything. It would be quite cumbersome. To compute the
address elf has to follow sh_info, which can be corrupted and therefore the
method has to return an ErrorOr. The address of the section is also the same
for every relocation in a section, so we shouldn't have to check the error
and fetch the value for every relocation.
* Use a getValue and make it up to the user to know what it is getting.
* Use a getOffset and:
* Assert for dynamic ELF objects. That is a very peculiar case and it is
probably fair to ask any tool that wants to support it to use ELF.h. The
only tool we have that reads those (llvm-readobj) already does that. The
only other use case I can think of is a dynamic linker.
* Check that COFF .obj files have sections with zero virtual address spaces. If
it turns out that some assembler/compiler produces these, we can change
COFFObjectFile::getRelocationOffset to subtract it. Given COFF format,
this can be done without the need for ErrorOr.
The getRelocationAddress method was never implemented for COFF. It also
had exactly one use in a very peculiar case: a shortcut for adding the
section value to a pcrel reloc on MachO.
Given that, I don't expect that there is any use out there of the C API. If
that is not the case, let me know and I will add it back with the implementation
inlined and do a proper deprecation.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@241450 91177308-0d34-0410-b5e6-96231b3b80d8
Lang Hames
Kevin Enderby
Steven Wu
Craig Topper
Kuba Brecka
NAKAMURA Takumi
Davide Italiano
Rafael Espindola