As mentioned by commit c5d38924dc6688c15b3fa133abeb3626e8f0767c (Apr 2020),
PC-relative entries avoid dynamic relocations and can therefore make the
section read-only.
This is similar to D78082 and D78590. We cannot commit to support
compiler/runtime built at different versions, so just don't play with versions.
For Mach-O support (incomplete yet), we use non-temporary `lxray_fn_idx[0-9]+`
symbols. Label differences are represented as a pair of UNSIGNED and SUBTRACTOR
relocations. The SUBTRACTOR external relocation requires r_extern==1 (needs to
reference a symbol table entry) which can be satisfied by `lxray_fn_idx[0-9]+`.
A `lxray_fn_idx[0-9]+` symbol also serves as the atom for this dead-strippable
section (follow-up to commit b9a134aa629de23a1dcf4be32e946e4e308fc64d).
Differential Revision: https://reviews.llvm.org/D152661
The Clang built-in function is void __xray_typedevent(size_t, const void *, size_t),
but the LLVM intrinsics has smaller integer types. Since we only allow
64-bit ELF/Mach-O targets, we can change llvm.xray.typedevent to
i64/ptr/i64.
This allows encoding more information and avoids i16 legalization for
many non-X86 targets.
fdrLoggingHandleTypedEvent only supports uint16_t event type.
Adds x-ray support for hexagon to llvm codegen, clang driver,
compiler-rt libs.
Differential Revision: https://reviews.llvm.org/D113638
Reapplying this after 543a9ad7c460bb8d641b1b7c67bbc032c9bfdb45,
which fixes the leak introduced there.
Building xray with recent clang on a 64-bit system results in a number
of -Wformat warnings:
compiler-rt/lib/xray/xray_allocator.h:70:11: warning: format specifies type 'int' but the argument has type '__sanitizer::uptr' (aka 'unsigned long') [-Wformat]
RoundedSize, B);
^~~~~~~~~~~
compiler-rt/lib/xray/xray_allocator.h:119:11: warning: format specifies type 'int' but the argument has type '__sanitizer::uptr' (aka 'unsigned long') [-Wformat]
RoundedSize, B);
^~~~~~~~~~~
Since `__sanitizer::uptr` has the same size as `size_t`, these can be
fixed by using the printf specifier `%zu`.
compiler-rt/lib/xray/xray_basic_logging.cpp:348:46: warning: format specifies type 'int' but the argument has type '__sanitizer::tid_t' (aka 'unsigned long long') [-Wformat]
Report("Cleaned up log for TID: %d\n", GetTid());
~~ ^~~~~~~~
%llu
compiler-rt/lib/xray/xray_basic_logging.cpp:353:62: warning: format specifies type 'int' but the argument has type '__sanitizer::tid_t' (aka 'unsigned long long') [-Wformat]
Report("Skipping buffer for TID: %d; Offset = %llu\n", GetTid(),
~~ ^~~~~~~~
%llu
Since `__sanitizer::tid_t` is effectively declared as `unsigned long
long`, these can be fixed by using the printf specifier `%llu`.
compiler-rt/lib/xray/xray_basic_logging.cpp:354:14: warning: format specifies type 'unsigned long long' but the argument has type 'size_t' (aka 'unsigned long') [-Wformat]
TLD.BufferOffset);
^~~~~~~~~~~~~~~~
Since `BufferOffset` is declared as `size_t`, this one can be fixed by
using `%zu` as a printf specifier.
compiler-rt/lib/xray/xray_interface.cpp:172:50: warning: format specifies type 'int' but the argument has type 'uint64_t' (aka 'unsigned long') [-Wformat]
Report("Unsupported sled kind '%d' @%04x\n", Sled.Address, int(Sled.Kind));
~~ ^~~~~~~~~~~~
%lu
Since ``xray::SledEntry::Address` is declared as `uint64_t`, this one
can be fixed by using `PRIu64`, and adding `<cinttypes>`.
compiler-rt/lib/xray/xray_interface.cpp:308:62: warning: format specifies type 'long long' but the argument has type 'size_t' (aka 'unsigned long') [-Wformat]
Report("System page size is not a power of two: %lld\n", PageSize);
~~~~ ^~~~~~~~
%zu
compiler-rt/lib/xray/xray_interface.cpp:359:64: warning: format specifies type 'long long' but the argument has type 'size_t' (aka 'unsigned long') [-Wformat]
Report("Provided page size is not a power of two: %lld\n", PageSize);
~~~~ ^~~~~~~~
%zu
Since `PageSize` is declared as `size_t`, these can be fixed by using
`%zu` as a printf specifier.
Reviewed By: vitalybuka
Differential Revision: https://reviews.llvm.org/D114469
Summary:
Add a flag to omit the xray_fn_idx to cut size overhead and relocations
roughly in half at the cost of reduced performance for single function
patching. Minor additions to compiler-rt support per-function patching
without the index.
Reviewers: dberris, MaskRay, johnislarry
Subscribers: hiraditya, arphaman, cfe-commits, #sanitizers, llvm-commits
Tags: #clang, #sanitizers, #llvm
Differential Revision: https://reviews.llvm.org/D81995
Follow-up of D78082 and D78590.
Otherwise, because xray_instr_map is now read-only, the absolute
relocation used for Sled.Function will cause a text relocation.
xray_instr_map contains absolute addresses of sleds, which are relocated
by `R_*_RELATIVE` when linked in -pie or -shared mode.
By making these addresses relative to PC, we can avoid the dynamic
relocations and remove the SHF_WRITE flag from xray_instr_map. We can
thus save VM pages containg xray_instr_map (because they are not
modified).
This patch changes x86-64 and bumps the sled version to 2. Subsequent
changes will change powerpc64le and AArch64.
Reviewed By: dberris, ianlevesque
Differential Revision: https://reviews.llvm.org/D78082
