In the textual format, `noduplicates` means no COMDAT/section group
deduplication is performed. Therefore, if both sets of sections are retained, and
they happen to define strong external symbols with the same names,
there will be a duplicate definition linker error.
In PE/COFF, the selection kind lowers to `IMAGE_COMDAT_SELECT_NODUPLICATES`.
The name describes the corollary instead of the immediate semantics. The name
can cause confusion to other binary formats (ELF, wasm) which have implemented/
want to implement the "no deduplication" selection kind. Rename it to be clearer.
Reviewed By: rnk
Differential Revision: https://reviews.llvm.org/D106319
Currently 1 byte global object has a ridiculous 63 bytes redzone.
This patch reduces the redzone size to be less than 32 if the size of global object is less than or equal to half of 32 (the minimal size of redzone).
A 12 bytes object has a 20 bytes redzone, a 20 bytes object has a 44 bytes redzone.
Reviewed By: MaskRay, #sanitizers, vitalybuka
Differential Revision: https://reviews.llvm.org/D102469
Under NPM, the asan-globals-md analysis is required but cannot be run
within the asan function pass due to module analyses not being able to
run from a function pass. So this pins all tests using "-asan" to the
legacy PM and adds a corresponding RUN line with
-passes='require<asan-globals-md>,function(asan)'.
Now all tests in Instrumentation/AddressSanitizer pass when
-enable-new-pm is by default on.
Tests were automatically converted using the following python script and
failures were manually fixed up.
import sys
for i in sys.argv:
with open(i, 'r') as f:
s = f.read()
with open(i, 'w') as f:
for l in s.splitlines():
if "RUN:" in l and ' -asan -asan-module ' in l and '\\' not in l:
f.write(l.replace(' -asan -asan-module ', ' -asan -asan-module -enable-new-pm=0 '))
f.write('\n')
f.write(l.replace(' -asan -asan-module ', " -passes='require<asan-globals-md>,function(asan),module(asan-module)' "))
f.write('\n')
elif "RUN:" in l and ' -asan ' in l and '\\' not in l:
f.write(l.replace(' -asan ', ' -asan -enable-new-pm=0 '))
f.write('\n')
f.write(l.replace(' -asan ', " -passes='require<asan-globals-md>,function(asan)' "))
f.write('\n')
else:
f.write(l)
f.write('\n')
See https://bugs.llvm.org/show_bug.cgi?id=46611.
Reviewed By: vitalybuka
Differential Revision: https://reviews.llvm.org/D83921
Summary:
This matches ELF.
This makes the number of ASan failures under the new pass manager on
Windows go from 18 to 1.
Under the old pass manager, the ASan module pass was one of the very
last things run, so these globals didn't get removed due to GlobalOpt.
But with the NPM the ASan module pass that adds these globals are run
much earlier in the pipeline and GlobalOpt ends up removing them.
Reviewers: vitalybuka, hans
Subscribers: hiraditya, llvm-commits
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D81175
Summary:
ICF prevented by removing unnamed_addr and local_unnamed_addr for all sanitized
globals.
Also in general unnamed_addr is not valid here as address now is important for
ODR violation detector and redzone poisoning.
Before the patch ICF on globals caused:
1. false ODR reports when we register global on the same address more than once
2. globals buffer overflow if we fold variables of smaller type inside of large
type. Then the smaller one will poison redzone which overlaps with the larger one.
Reviewers: eugenis, pcc
Subscribers: hiraditya, llvm-commits
Differential Revision: https://reviews.llvm.org/D55857
llvm-svn: 349706
Use a combination of !associated, comdat, @llvm.compiler.used and
custom sections to allow dead stripping of globals and their asan
metadata. Sometimes.
Currently this works on LLD, which supports SHF_LINK_ORDER with
sh_link pointing to the associated section.
This also works on BFD, which seems to treat comdats as
all-or-nothing with respect to linker GC. There is a weird quirk
where the "first" global in each link is never GC-ed because of the
section symbols.
At this moment it does not work on Gold (as in the globals are never
stripped).
This is a second re-land of r298158. This time, this feature is
limited to -fdata-sections builds.
llvm-svn: 301587
This way, when the linker adds padding between globals, we can skip over
the zero padding bytes and reliably find the start of the next metadata
global.
llvm-svn: 288096
Summary:
This is similar to what was done for Darwin in rL264645 /
http://reviews.llvm.org/D16737, but it uses COFF COMDATs to achive the
same result instead of relying on new custom linker features.
As on MachO, this creates one metadata global per instrumented global.
The metadata global is placed in the custom .ASAN$GL section, which the
ASan runtime will iterate over during initialization. There are no other
references to the metadata, so normal linker dead stripping would
discard it. However, the metadata is put in a COMDAT group with the
instrumented global, so that it will be discarded if and only if the
instrumented global is discarded.
I didn't update the ASan ABI version check since this doesn't affect
non-Windows platforms, and the WinASan ABI isn't really stable yet.
Implementing this for ELF will require extending LLVM IR and MC a bit so
that we can use non-COMDAT section groups.
Reviewers: pcc, kcc, mehdi_amini, kubabrecka
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D26770
llvm-svn: 287576
Arthur Eubanks