Summary: This protects lld from a null pointer dereference when a faulty input file has such invalid sh_link fields.
Reviewers: ruiu, espindola
Reviewed By: ruiu
Subscribers: emaste, arichardson, llvm-commits
Differential Revision: https://reviews.llvm.org/D51743
llvm-svn: 341611
Summary:
r338767 updated the COFF and wasm linker SymbolTable code to be
strutured more like the ELF linker's. That inadvertedly changed the
behavior of the COFF linker so that lazy symbols would be marked as
used in regular objects. This change adds an overload of the insert()
function, similar to the ELF linker, which does not perform that
marking.
Reviewers: ruiu, rnk, hans
Subscribers: aheejin, sunfish, llvm-commits
Differential Revision: https://reviews.llvm.org/D51720
llvm-svn: 341585
If the coff timestamp is set to a hash, like lld-link does if /Brepro is
passed, the coff spec suggests that a IMAGE_DEBUG_TYPE_REPRO entry is in the
debug directory. This lets lld-link write such a section.
Fixes PR38429, see bug for details.
Differential Revision: https://reviews.llvm.org/D51652
llvm-svn: 341486
section will not have an input file. Don't crash under those circumstances.
Neither clang nor llvm-mc generates R_X86_64_PC32 relocations due to
https://reviews.llvm.org/D43383, which makes it hard to write a test case.
However, gcc does generate such relocations. I want to get a fix in now,
but will figure out a way to actually exercise this code path as soon
as I can.
llvm-svn: 341408
When building a shared libc++.dll, it pulls in libc++abi.a statically
with the --wholearchive flag. If such a build is done with
--export-all-symbols, it's reasonable to assume that everything
from that library also should be exported with the same rules as normal
local object files, even though we normally avoid autoexporting things
from libc++abi.a in other cases when linking a DLL (user code).
Differential Revision: https://reviews.llvm.org/D51529
llvm-svn: 341403
Following D50807, and heading towards D50664, this intermediary change does the following:
1. Upgrade all custom Error types in llvm/trunk/lib/DebugInfo/ to use the new StringError behavior (D50807).
2. Implement std::is_error_code_enum and make_error_code() for DebugInfo error enumerations.
3. Rename GenericError -> PDBError (the file will be renamed in a subsequent commit)
4. Update custom error messages to follow the same formatting: (\w\s*)+\.
5. Keep generic "file not found" (ENOENT) errors as they are in PDB code. Previously, there used to be a custom enumeration for that purpose.
6. Remove a few extraneous LF in log() implementations. Printing LF is a responsability at a higher level, not at the error level.
Differential Revision: https://reviews.llvm.org/D51499
llvm-svn: 341228
This patch moves the checking for too large offsets into merge sections
earlier.
Without this change the large offset generated in the added test-case
will cause an assert (as it happens to be a value reserved as a
"tombstone" in the DenseMap implementation) when OffsetMap is queried in
getSectionPiece().
To simplify the code and avoid future mistakes I have refactored so that
there is only one function that looks up offsets in the OffsetMap.
Differential Revision: https://reviews.llvm.org/D51180
llvm-svn: 341206
After fixing up the runtime pseudo relocation, the .refptr.<var>
will be a plain pointer with the same value as the IAT entry itself.
To save a little binary size and reduce the number of runtime pseudo
relocations, redirect references to the IAT entry (via the __imp_<var>
symbol) itself and discard the .refptr.<var> chunk (as long as the
same section chunk doesn't contain anything else than the single
pointer).
As there are now cases for both setting the Live variable to true
and false externally, remove the accessors and setters and just make
the variable public instead.
Differential Revision: https://reviews.llvm.org/D51456
llvm-svn: 341175
It's always replaced with the same (short) static string, so just put that
there directly.
No intended behavior change.
https://reviews.llvm.org/D51357
llvm-svn: 341134
Since the order and placement of the non-wanted elements might not
be obvious, it feels more straightforward to hardcode the whole list
with -NEXT elements (and checking for the end of the output with
CHECK-EMPTY) instead of adding CHECK-NOT lines at the right places
where the unwanted elements would appear if they erroneously
were to included.
llvm-svn: 341016
These symbols are declared early with the same value, so they otherwise
appear identical to ICF.
Differential Revision: https://reviews.llvm.org/D51376
llvm-svn: 340998
This builds all dependencies of lld-test/check-lld, without running
the tests. This matches llvm-test-depends and clang-test-depends.
Differential Revision: https://reviews.llvm.org/D51439
llvm-svn: 340943
There's no point in keeping them as separate sections.
This differs from GNU ld, which places .ctors and .dtors content in
.text (implemented by a built-in linker script). But since the content
only is pointers, there's no need to have it executable.
GNU ld also leaves .CRT separate as its own standalone section.
MSVC merges .CRT into .rdata similarly, with a directive embedded in
an object file in msvcrt.lib or libcmt.lib.
Differential Revision: https://reviews.llvm.org/D51414
llvm-svn: 340940
With this patch, lld creates a .note.GNU_stack and adds that to an
output file if it is creating a re-linkable object file (i.e. if -r
is given). If we don't do this, and if you use GNU linkers as a final
linker, they create an executable whose stack area is executable,
which is considered pretty bad these days.
Differential Revision: https://reviews.llvm.org/D51400
llvm-svn: 340902
Relanding r340564, original commit message:
Fixes the handling of *_DS relocations used on DQ-form instructions where we
were overwriting some of the extended opcode bits. Also adds an alignment check
so that the user will receive a diagnostic error if the value we are writing
is not properly aligned.
Differential Revision: https://reviews.llvm.org/D51124
llvm-svn: 340832
Looking at the current implementation and algorithm description,
it does not seem we need to keep vector with all edges for
each cluster and can just remember the best one. This is NFC change.
Differential revision: https://reviews.llvm.org/D50609
llvm-svn: 340806
Normally, in order to reference exported data symbols from a different
DLL, the declarations need to have the dllimport attribute, in order to
use the __imp_<var> symbol (which contains an address to the actual
variable) instead of the variable itself directly. This isn't an issue
in the same way for functions, since any reference to the function without
the dllimport attribute will end up as a reference to a thunk which loads
the actual target function from the import address table (IAT).
GNU ld, in MinGW environments, supports automatically importing data
symbols from DLLs, even if the references didn't have the appropriate
dllimport attribute. Since the PE/COFF format doesn't support the kind
of relocations that this would require, the MinGW's CRT startup code
has an custom framework of their own for manually fixing the missing
relocations once module is loaded and the target addresses in the IAT
are known.
For this to work, the linker (originall in GNU ld) creates a list of
remaining references needing fixup, which the runtime processes on
startup before handing over control to user code.
While this feature is rather controversial, it's one of the main features
allowing unix style libraries to be used on windows without any extra
porting effort.
Some sort of automatic fixing of data imports is also necessary for the
itanium C++ ABI on windows (as clang implements it right now) for importing
vtable pointers in certain cases, see D43184 for some discussion on that.
The runtime pseudo relocation handler supports 8/16/32/64 bit addresses,
either PC relative references (like IMAGE_REL_*_REL32*) or absolute
references (IMAGE_REL_AMD64_ADDR32, IMAGE_REL_AMD64_ADDR32,
IMAGE_REL_I386_DIR32). On linking, the relocation is handled as a
relocation against the corresponding IAT slot. For the absolute references,
a normal base relocation is created, to update the embedded address
in case the image is loaded at a different address.
The list of runtime pseudo relocations contains the RVA of the
imported symbol (the IAT slot), the RVA of the location the relocation
should be applied to, and a size of the memory location. When the
relocations are fixed at runtime, the difference between the actual
IAT slot value and the IAT slot address is added to the reference,
doing the right thing for both absolute and relative references.
With this patch alone, things work fine for i386 binaries, and mostly
for x86_64 binaries, with feature parity with GNU ld. Despite this,
there are a few gotchas:
- References to data from within code works fine on both x86 architectures,
since their relocations consist of plain 32 or 64 bit absolute/relative
references. On ARM and AArch64, references to data doesn't consist of
a plain 32 or 64 bit embedded address or offset in the code. On ARMNT,
it's usually a MOVW+MOVT instruction pair represented by a
IMAGE_REL_ARM_MOV32T relocation, each instruction containing 16 bit of
the target address), on AArch64, it's usually an ADRP+ADD/LDR/STR
instruction pair with an even more complex encoding, storing a PC
relative address (with a range of +/- 4 GB). This could theoretically
be remedied by extending the runtime pseudo relocation handler with new
relocation types, to support these instruction encodings. This isn't an
issue for GCC/GNU ld since they don't support windows on ARMNT/AArch64.
- For x86_64, if references in code are encoded as 32 bit PC relative
offsets, the runtime relocation will fail if the target turns out to be
out of range for a 32 bit offset.
- Fixing up the relocations at runtime requires making sections writable
if necessary, with the VirtualProtect function. In Windows Store/UWP apps,
this function is forbidden.
These limitations are addressed by a few later patches in lld and
llvm.
Differential Revision: https://reviews.llvm.org/D50917
llvm-svn: 340726
For this relocation, which applies to two consecutive instructions,
it's plausible that the second instruction might not actually be
the right one.
Differential Revision: https://reviews.llvm.org/D50998
llvm-svn: 340715
I removed the ".exe" regex in the wrong place. lld-link in front of the
"error:" no longer has the suffix; the --plugin-opt diagnostic still has it.
llvm-svn: 340590
This reverts commit 5125b44dbb5d06b715213e4bec75c7346bfcc7d3.
ppc64-dq.s and ppc64-error-missaligned-dq.s fail on several of the build-bots.
Reverting to investigate.
llvm-svn: 340568
Fixes the handling of *_DS relocations used on DQ-form instructions where we
were overwriting some of the extended opcode bits. Also adds an alignment check
so that the user will receive a diagnostic error if the value we are writing
is not properly aligned.
Differential Revision: https://reviews.llvm.org/D51124
llvm-svn: 340564
This is a minor follow-up to https://reviews.llvm.org/D49189. On Windows, lld
used to print "lld-link.exe: error: ...". Now it just prints "lld-link: error:
...". This matches what link.exe does (it prints "LINK : ...") and makes lld's
output less dependent on the host system.
https://reviews.llvm.org/D51133
llvm-svn: 340487
newline() in ErrorHandler.cpp already tries to insert newlines between messages
that contain embedded newlines, so getSymbolLocations() shouldn't return a
string that ends in a newline -- else we end up with two newlines between error
messages.
Makes lld-link's output look more like ld.lld output.
https://reviews.llvm.org/D51117
llvm-svn: 340482
