Summary:
This change ensures that the .dynsym section will be parsed even when there's already is a .symtab.
It is motivated because of minidebuginfo (https://sourceware.org/gdb/current/onlinedocs/gdb/MiniDebugInfo.html#MiniDebugInfo).
There it says:
Keep all the function symbols not already in the dynamic symbol table.
That means the .symtab embedded inside the .gnu_debugdata does NOT contain the symbols from .dynsym. But in order to put a breakpoint on all symbols we need to load both. I hope this makes sense.
My other patch D66791 implements support for minidebuginfo, that's why I need this change.
Reviewers: labath, espindola, alexshap
Subscribers: JDevlieghere, emaste, arichardson, MaskRay, lldb-commits
Tags: #lldb
Differential Revision: https://reviews.llvm.org/D67390
llvm-svn: 371599
Summary:
In an attempt to make file-address-based lookups more predictable, in D55998
we started ignoring sections which would result in file address
overlaps. It turns out this was too aggressive because thread-local
sections typically will have file addresses which apear to overlap
regular data/code. This does not cause a problem at runtime because
thread-local sections are loaded into memory using special logic, but it
can cause problems for lldb when trying to lookup objects by their file
address.
This patch changes ObjectFileELF to permit thread-local sections to
overlap regular ones by essentially giving them a separate address
space. It also makes them more symmetrical to regular sections by
creating container sections from PT_TLS segments.
Simultaneously, the patch changes the regular file address lookup logic
to ignore sections with the thread-specific bit set. I believe this is
what the users looking up file addresses would typically expect, as
looking up thread-local data generally requires more complex logic (e.g.
DWARF has a special opcode for that).
Reviewers: clayborg, jingham, MaskRay
Subscribers: emaste, aprantl, arichardson, lldb-commits
Differential Revision: https://reviews.llvm.org/D65282
llvm-svn: 368010
Summary:
The debug link and build-id lookups are two independent ways one can
search for a separate symbol file. However, our implementation in
SymbolVendorELF was tying the two together and refusing to look up the
symbol file based on a build id if the file did not contain a debug
link.
This patch makes it possible to search for the symbol file with
just one of the two methods available. To demonstrate, I split the
build-id-case test into two, so that we test the search using both
methods.
Reviewers: jankratochvil, mgorny, clayborg, espindola, alexshap
Subscribers: emaste, arichardson, MaskRay, lldb-commits
Differential Revision: https://reviews.llvm.org/D65561
llvm-svn: 367994
With this style, a compressed section is indicated by a "z" in the section
name, instead of a section header flag. This patch consists of two small tweaks:
- use an llvm Decompressor method in order to properly detect compressed sections
- make sure we recognise .zdebug_info (and friends) when classifying section types.
llvm-svn: 365654
Split the recognition into NetBSD executables & shared libraries
and core(5) files.
Introduce new owner type: "NetBSD-CORE", as core(5) files are not tagged
in the same way as regular NetBSD executables.
Stop using incorrectly ABI_TAG and ABI_SIZE. Introduce IDENT_TAG,
IDENT_DECSZ, IDENT_NAMESZ and PROCINFO.
The new values detect correctly the NetBSD images.
The patch has been originally written by Kamil Rytarowski. I've added
tests and applied minor code changes per review. The work has been
sponsored by the NetBSD Foundation.
Differential Revision: https://reviews.llvm.org/D42870
llvm-svn: 354466
The code was assuming that the elf file will have a PT_LOAD segment
starting from the first byte of the file. While this is true for files
generated by most linkers (it's a way of saving space), it is not a
requirement. And files not satisfying this constraint can still be
perfectly executable. yaml2obj is one of the tools which produces files
like this.
This patch relaxes the check in ObjectFileELF to take the address of the
first PT_LOAD segment as the base address of the object (instead of the
one with the offset 0). Since the PT_LOAD segments are supposed to be
sorted according to the VM address, this entry will also be the one with
the lowest VM address.
If we ever run into files which don't have the PT_LOAD segments sorted,
we can easily change this code to return the lowest VM address as the
base address (if that is the correct thing to do for these files).
llvm-svn: 350923
Summary:
The concept of a base address was already present in the implementation
(it's needed for computing section load addresses properly), but it was
never exposed through this function. This fixes that.
llvm-svn: 350804
Summary:
This is the result of the discussion in D55356, where it was suggested
as a solution to representing the addresses that logically belong to a
module in memory, but are not a part of any of its sections.
The ELF PT_LOAD segments are similar to the MachO "load commands",
except that the relationship between them and the object file sections
is a bit weaker. While in the MachO case, the sections belonging to a
specific segment are placed directly inside it in the object file
logical structur, in the ELF case, the sections and segments form two
separate hierarchies. This means that it is in theory possible to create
an elf file where only a part of a section would belong to some segment
(and another part to a different one). However, I am not aware of any
tool which would produce such a file (and most tools will have problems
ingesting them), so this means it is still possible to follow the MachO
model and make sections children of the PT_LOAD segments.
In case we run into (corrupt?) files with overlapping sections, I have
added code (and tests) which adjusts the sizes and/or drops the offending
sections in order to present a reasonable image to the upper layers of
LLDB. This is mostly done for completeness, as I don't anticipate
running into this situation in the real world. However, if we do run
into it, and the current behavior is not suitable for some reason, we
can implement this logic differently.
Reviewers: clayborg, jankratochvil, krytarowski, joerg, espindola
Subscribers: emaste, arichardson, lldb-commits
Differential Revision: https://reviews.llvm.org/D55998
llvm-svn: 350742
Summary:
The first section header does not define a real section. Instead it is
used for various elf extensions. This patch skips creation of a section
for index 0.
This has one furtunate side-effect, in that it allows us to use the section
header index as the Section ID (where 0 is also invalid). This way, we
can get rid of a lot of spurious +1s in the ObjectFileELF code.
Reviewers: clayborg, krytarowski, joerg, espindola
Subscribers: emaste, lldb-commits, arichardson
Differential Revision: https://reviews.llvm.org/D55757
llvm-svn: 349498
Summary:
This patch attempts to move as much code as possible out of the
CreateSections function to make room for future improvements there. Some
of this may be slightly over-engineered (VMAddressProvider), but I
wanted to keep the logic of this function very simple, because once I
start taking segment headers into acount (as discussed in D55356), the
function is going to grow significantly.
While in there, I also added tests for various bits of functionality.
This should be NFC, except that I changed the order of hac^H^Heuristicks
for determining section type slightly. Previously, name-based deduction
(.symtab -> symtab) would take precedence over type-based (SHT_SYMTAB ->
symtab) one. In fact we would assert if we ran into a .text section with
type SHT_SYMTAB. Though unlikely to matter in practice, this order
seemed wrong to me, so I have inverted it.
Reviewers: clayborg, krytarowski, espindola
Subscribers: emaste, arichardson, lldb-commits
Differential Revision: https://reviews.llvm.org/D55706
llvm-svn: 349268
We've recently developed a convention where the tests are placed into
subfolders according to the object file type. This applies that
convention to existing tests too.
llvm-svn: 349027
Konrad Kleine