[libcxx] [libunwind] [DRAFT][libc++] Switch FreeBSD to C++26 (PR #86658)
Ed Maste via cfe-commits
cfe-commits at lists.llvm.org
Tue Mar 26 05:37:53 PDT 2024
https://github.com/emaste created https://github.com/llvm/llvm-project/pull/86658
As discussed in #86320; opening this PR for CI.
It looks like (prior to this change) there are no C++26 jobs right now.
>From 6cf1345feee41ec3bad51ba853091e35723c85ab Mon Sep 17 00:00:00 2001
From: Dmitry Chagin <dchagin at FreeBSD.org>
Date: Thu, 12 Oct 2023 16:02:06 +0300
Subject: [PATCH 1/2] [libunwind] Unwind through aarch64/FreeBSD sigreturn
frame
Similar to D90898 (Linux Aarch64).
Differential Revision: https://reviews.llvm.org/D155066
---
libunwind/include/__libunwind_config.h | 5 ++
libunwind/src/UnwindCursor.hpp | 85 ++++++++++++++++++++++++--
2 files changed, 84 insertions(+), 6 deletions(-)
diff --git a/libunwind/include/__libunwind_config.h b/libunwind/include/__libunwind_config.h
index 8db336b2d727ce..783a488d7de0fd 100644
--- a/libunwind/include/__libunwind_config.h
+++ b/libunwind/include/__libunwind_config.h
@@ -39,6 +39,9 @@
# if defined(__HAIKU__)
# define _LIBUNWIND_TARGET_HAIKU 1
# endif
+#if defined(__FreeBSD__)
+#define _LIBUNWIND_TARGET_FREEBSD 1
+#endif
# if defined(__i386__)
# define _LIBUNWIND_TARGET_I386
# define _LIBUNWIND_CONTEXT_SIZE 8
@@ -73,6 +76,8 @@
# define _LIBUNWIND_CONTEXT_SIZE 66
# if defined(__SEH__)
# define _LIBUNWIND_CURSOR_SIZE 164
+#elif defined(_LIBUNWIND_TARGET_FREEBSD)
+#define _LIBUNWIND_CURSOR_SIZE 80
# else
# define _LIBUNWIND_CURSOR_SIZE 78
# endif
diff --git a/libunwind/src/UnwindCursor.hpp b/libunwind/src/UnwindCursor.hpp
index 7753936a5894a3..96d82d6aac7c93 100644
--- a/libunwind/src/UnwindCursor.hpp
+++ b/libunwind/src/UnwindCursor.hpp
@@ -39,6 +39,17 @@
#include <sys/uio.h>
#include <unistd.h>
#define _LIBUNWIND_CHECK_LINUX_SIGRETURN 1
+#define _LIBUNWIND_CHECK_SIGRETURN 1
+#endif
+
+#if defined(_LIBUNWIND_TARGET_FREEBSD) && defined(_LIBUNWIND_TARGET_AARCH64)
+#include <machine/frame.h>
+#include <sys/sysctl.h>
+#include <sys/ucontext.h>
+#include <sys/user.h>
+#include <unistd.h>
+#define _LIBUNWIND_CHECK_FREEBSD_SIGRETURN 1
+#define _LIBUNWIND_CHECK_SIGRETURN 1
#endif
#include "AddressSpace.hpp"
@@ -983,7 +994,7 @@ class UnwindCursor : public AbstractUnwindCursor{
}
#endif
-#if defined(_LIBUNWIND_CHECK_LINUX_SIGRETURN)
+#if defined(_LIBUNWIND_CHECK_SIGRETURN)
bool setInfoForSigReturn() {
R dummy;
return setInfoForSigReturn(dummy);
@@ -1011,7 +1022,7 @@ class UnwindCursor : public AbstractUnwindCursor{
template <typename Registers> int stepThroughSigReturn(Registers &) {
return UNW_STEP_END;
}
-#endif
+#endif // defined(_LIBUNWIND_CHECK_SIGRETURN)
#if defined(_LIBUNWIND_SUPPORT_DWARF_UNWIND)
bool getInfoFromFdeCie(const typename CFI_Parser<A>::FDE_Info &fdeInfo,
@@ -1314,9 +1325,14 @@ class UnwindCursor : public AbstractUnwindCursor{
unw_proc_info_t _info;
bool _unwindInfoMissing;
bool _isSignalFrame;
-#if defined(_LIBUNWIND_CHECK_LINUX_SIGRETURN)
+#if defined(_LIBUNWIND_CHECK_SIGRETURN)
bool _isSigReturn = false;
+#if defined(_LIBUNWIND_CHECK_FREEBSD_SIGRETURN)
+ bool _isSigTrampDetermined = false;
+ pint_t _sigTrampStart;
+ pint_t _sigTrampEnd;
#endif
+#endif // defined(_LIBUNWIND_CHECK_SIGRETURN)
};
@@ -2558,7 +2574,7 @@ int UnwindCursor<A, R>::stepWithTBTable(pint_t pc, tbtable *TBTable,
template <typename A, typename R>
void UnwindCursor<A, R>::setInfoBasedOnIPRegister(bool isReturnAddress) {
-#if defined(_LIBUNWIND_CHECK_LINUX_SIGRETURN)
+#if defined(_LIBUNWIND_CHECK_SIGRETURN)
_isSigReturn = false;
#endif
@@ -2673,7 +2689,7 @@ void UnwindCursor<A, R>::setInfoBasedOnIPRegister(bool isReturnAddress) {
}
#endif // #if defined(_LIBUNWIND_SUPPORT_DWARF_UNWIND)
-#if defined(_LIBUNWIND_CHECK_LINUX_SIGRETURN)
+#if defined(_LIBUNWIND_CHECK_SIGRETURN)
if (setInfoForSigReturn())
return;
#endif
@@ -2909,6 +2925,63 @@ int UnwindCursor<A, R>::stepThroughSigReturn(Registers_s390x &) {
#endif // defined(_LIBUNWIND_CHECK_LINUX_SIGRETURN) &&
// defined(_LIBUNWIND_TARGET_S390X)
+#if defined(_LIBUNWIND_CHECK_FREEBSD_SIGRETURN) && \
+ defined(_LIBUNWIND_TARGET_AARCH64)
+template <typename A, typename R>
+bool UnwindCursor<A, R>::setInfoForSigReturn(Registers_arm64 &) {
+ // Look for the sigreturn trampoline.
+ //
+ // https://cgit.freebsd.org/src/tree/sys/arm64/arm64/sigtramp.S
+ const pint_t pc = static_cast<pint_t>(this->getReg(UNW_REG_IP));
+
+ if (_isSigTrampDetermined == false) {
+ struct kinfo_sigtramp kst = {0};
+ size_t len = sizeof(kst);
+ int mib[4] = {CTL_KERN, KERN_PROC, KERN_PROC_SIGTRAMP, getpid()};
+ if (sysctl(mib, 4, &kst, &len, NULL, 0) == 0) {
+ _isSigTrampDetermined = true;
+ _sigTrampStart = reinterpret_cast<pint_t>(kst.ksigtramp_start);
+ _sigTrampEnd = reinterpret_cast<pint_t>(kst.ksigtramp_end);
+ }
+ }
+
+ if (_isSigTrampDetermined == false ||
+ (pc < _sigTrampStart || pc >= _sigTrampEnd))
+ return false;
+
+ _info = {};
+ _info.start_ip = _sigTrampStart;
+ _info.end_ip = _sigTrampEnd;
+ _isSigReturn = true;
+ return true;
+}
+
+template <typename A, typename R>
+int UnwindCursor<A, R>::stepThroughSigReturn(Registers_arm64 &) {
+ // In the signal trampoline frame, sp points to a sigframe
+ const pint_t kOffsetSpToSigcontext =
+ offsetof(struct sigframe, sf_uc) + offsetof(ucontext_t, uc_mcontext);
+
+ // Offsets from mcontext_t to each register.
+ const pint_t kOffsetGprs = offsetof(struct gpregs, gp_x[0]);
+ const pint_t kOffsetSp = offsetof(struct gpregs, gp_sp);
+ const pint_t kOffsetPc = offsetof(struct gpregs, gp_lr);
+
+ pint_t sigctx = _registers.getSP() + kOffsetSpToSigcontext;
+
+ for (int i = 0; i <= 29; ++i) {
+ uint64_t value =
+ _addressSpace.get64(sigctx + kOffsetGprs + static_cast<pint_t>(i * 8));
+ _registers.setRegister(UNW_AARCH64_X0 + i, value);
+ }
+ _registers.setSP(_addressSpace.get64(sigctx + kOffsetSp));
+ _registers.setIP(_addressSpace.get64(sigctx + kOffsetPc));
+ _isSignalFrame = true;
+ return UNW_STEP_SUCCESS;
+}
+#endif // defined(_LIBUNWIND_CHECK_FREEBSD_SIGRETURN) &&
+ // defined(_LIBUNWIND_TARGET_AARCH64)
+
template <typename A, typename R> int UnwindCursor<A, R>::step(bool stage2) {
(void)stage2;
// Bottom of stack is defined is when unwind info cannot be found.
@@ -2917,7 +2990,7 @@ template <typename A, typename R> int UnwindCursor<A, R>::step(bool stage2) {
// Use unwinding info to modify register set as if function returned.
int result;
-#if defined(_LIBUNWIND_CHECK_LINUX_SIGRETURN)
+#if defined(_LIBUNWIND_CHECK_SIGRETURN)
if (_isSigReturn) {
result = this->stepThroughSigReturn();
} else
>From d4cbaa14442965099d44cae3f3b82f932e447648 Mon Sep 17 00:00:00 2001
From: Ed Maste <emaste at FreeBSD.org>
Date: Tue, 26 Mar 2024 08:34:40 -0400
Subject: [PATCH 2/2] [draft][libc++] Switch FreeBSD CI job to C++26
---
libcxx/utils/ci/buildkite-pipeline.yml | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/libcxx/utils/ci/buildkite-pipeline.yml b/libcxx/utils/ci/buildkite-pipeline.yml
index 31e794e67d330d..c43e414418729a 100644
--- a/libcxx/utils/ci/buildkite-pipeline.yml
+++ b/libcxx/utils/ci/buildkite-pipeline.yml
@@ -207,7 +207,7 @@ steps:
- group: ':freebsd: FreeBSD'
steps:
- label: FreeBSD 13 amd64
- command: libcxx/utils/ci/run-buildbot generic-cxx23
+ command: libcxx/utils/ci/run-buildbot generic-cxx26
env:
CC: clang17
CXX: clang++17
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