[libunwind] Export the unw_* symbols as weak symbols
libunwind defines the _Unwind_* ABI used by libc++abi. This ABI is a
stable quasi-standard common between multiple implementations such as
LLVM and GNU. The _U* symbol name space is also safely within the symbol
name space that standard C & C++ reserve for the implementation.
Futhermore, libunwind also defines several unw_* symbols, and references
these from the _Unwind_* entry points so the standard/reserved part of
the ABI is dependent on the unw_* part of the ABI. This is not OK for a
C or C++ implementation. The unw_* symbols are reserved for C and extern
"C" used by application code.
This change renames each unw_* function to __unw* and adds a weak alias
unw_* to keep the public <libunwind.h> ABI unchanged for backwards
compatibility. Every reference to unw_* in the implementation has been
changed to use __unw* so that if other unw_* definitions are in force
because nothing uses <libunwind.h> in a particular program, no _Unwind*
code path depends on any unw_* symbol. Furthemore, __unw_* symbols are
hidden, which saves PLT overhead in the shared library case.
In the future, we should cconsider untangling the unw_* API/ABI from the
_Unwind_* API/ABI. The internal API backing the _Unwind_* ABI
implementation should not rely on any nonstandard symbols not in the
implementation-reserved name space. This would then allow separating the
_Unwind_* API/ABI from unw_* entirely, but that's a more substantial
change that's going to require more significant refactoring.
Differential Revision: https://reviews.llvm.org/D59921
llvm-svn: 357640
Cr-Mirrored-From: sso://chromium.googlesource.com/_direct/external/github.com/llvm/llvm-project
Cr-Mirrored-Commit: e369a989fc37248f4aa05ab2d184270ac27b22e1
diff --git a/src/libunwind.cpp b/src/libunwind.cpp
index 03dfeae..5f99337 100644
--- a/src/libunwind.cpp
+++ b/src/libunwind.cpp
@@ -29,15 +29,11 @@
_LIBUNWIND_EXPORT unw_addr_space_t unw_local_addr_space =
(unw_addr_space_t)&LocalAddressSpace::sThisAddressSpace;
-/// record the registers and stack position of the caller
-extern int unw_getcontext(unw_context_t *);
-// note: unw_getcontext() implemented in assembly
-
/// Create a cursor of a thread in this process given 'context' recorded by
-/// unw_getcontext().
-_LIBUNWIND_EXPORT int unw_init_local(unw_cursor_t *cursor,
- unw_context_t *context) {
- _LIBUNWIND_TRACE_API("unw_init_local(cursor=%p, context=%p)",
+/// __unw_getcontext().
+_LIBUNWIND_HIDDEN int __unw_init_local(unw_cursor_t *cursor,
+ unw_context_t *context) {
+ _LIBUNWIND_TRACE_API("__unw_init_local(cursor=%p, context=%p)",
static_cast<void *>(cursor),
static_cast<void *>(context));
#if defined(__i386__)
@@ -75,11 +71,12 @@
return UNW_ESUCCESS;
}
+_LIBUNWIND_WEAK_ALIAS(__unw_init_local, unw_init_local)
/// Get value of specified register at cursor position in stack frame.
-_LIBUNWIND_EXPORT int unw_get_reg(unw_cursor_t *cursor, unw_regnum_t regNum,
- unw_word_t *value) {
- _LIBUNWIND_TRACE_API("unw_get_reg(cursor=%p, regNum=%d, &value=%p)",
+_LIBUNWIND_HIDDEN int __unw_get_reg(unw_cursor_t *cursor, unw_regnum_t regNum,
+ unw_word_t *value) {
+ _LIBUNWIND_TRACE_API("__unw_get_reg(cursor=%p, regNum=%d, &value=%p)",
static_cast<void *>(cursor), regNum,
static_cast<void *>(value));
AbstractUnwindCursor *co = (AbstractUnwindCursor *)cursor;
@@ -89,12 +86,13 @@
}
return UNW_EBADREG;
}
-
+_LIBUNWIND_WEAK_ALIAS(__unw_get_reg, unw_get_reg)
/// Set value of specified register at cursor position in stack frame.
-_LIBUNWIND_EXPORT int unw_set_reg(unw_cursor_t *cursor, unw_regnum_t regNum,
- unw_word_t value) {
- _LIBUNWIND_TRACE_API("unw_set_reg(cursor=%p, regNum=%d, value=0x%" PRIxPTR ")",
+_LIBUNWIND_HIDDEN int __unw_set_reg(unw_cursor_t *cursor, unw_regnum_t regNum,
+ unw_word_t value) {
+ _LIBUNWIND_TRACE_API("__unw_set_reg(cursor=%p, regNum=%d, value=0x%" PRIxPTR
+ ")",
static_cast<void *>(cursor), regNum, value);
typedef LocalAddressSpace::pint_t pint_t;
AbstractUnwindCursor *co = (AbstractUnwindCursor *)cursor;
@@ -120,12 +118,12 @@
}
return UNW_EBADREG;
}
-
+_LIBUNWIND_WEAK_ALIAS(__unw_set_reg, unw_set_reg)
/// Get value of specified float register at cursor position in stack frame.
-_LIBUNWIND_EXPORT int unw_get_fpreg(unw_cursor_t *cursor, unw_regnum_t regNum,
- unw_fpreg_t *value) {
- _LIBUNWIND_TRACE_API("unw_get_fpreg(cursor=%p, regNum=%d, &value=%p)",
+_LIBUNWIND_HIDDEN int __unw_get_fpreg(unw_cursor_t *cursor, unw_regnum_t regNum,
+ unw_fpreg_t *value) {
+ _LIBUNWIND_TRACE_API("__unw_get_fpreg(cursor=%p, regNum=%d, &value=%p)",
static_cast<void *>(cursor), regNum,
static_cast<void *>(value));
AbstractUnwindCursor *co = (AbstractUnwindCursor *)cursor;
@@ -135,16 +133,16 @@
}
return UNW_EBADREG;
}
-
+_LIBUNWIND_WEAK_ALIAS(__unw_get_fpreg, unw_get_fpreg)
/// Set value of specified float register at cursor position in stack frame.
-_LIBUNWIND_EXPORT int unw_set_fpreg(unw_cursor_t *cursor, unw_regnum_t regNum,
- unw_fpreg_t value) {
+_LIBUNWIND_HIDDEN int __unw_set_fpreg(unw_cursor_t *cursor, unw_regnum_t regNum,
+ unw_fpreg_t value) {
#if defined(_LIBUNWIND_ARM_EHABI)
- _LIBUNWIND_TRACE_API("unw_set_fpreg(cursor=%p, regNum=%d, value=%llX)",
+ _LIBUNWIND_TRACE_API("__unw_set_fpreg(cursor=%p, regNum=%d, value=%llX)",
static_cast<void *>(cursor), regNum, value);
#else
- _LIBUNWIND_TRACE_API("unw_set_fpreg(cursor=%p, regNum=%d, value=%g)",
+ _LIBUNWIND_TRACE_API("__unw_set_fpreg(cursor=%p, regNum=%d, value=%g)",
static_cast<void *>(cursor), regNum, value);
#endif
AbstractUnwindCursor *co = (AbstractUnwindCursor *)cursor;
@@ -154,20 +152,20 @@
}
return UNW_EBADREG;
}
-
+_LIBUNWIND_WEAK_ALIAS(__unw_set_fpreg, unw_set_fpreg)
/// Move cursor to next frame.
-_LIBUNWIND_EXPORT int unw_step(unw_cursor_t *cursor) {
- _LIBUNWIND_TRACE_API("unw_step(cursor=%p)", static_cast<void *>(cursor));
+_LIBUNWIND_HIDDEN int __unw_step(unw_cursor_t *cursor) {
+ _LIBUNWIND_TRACE_API("__unw_step(cursor=%p)", static_cast<void *>(cursor));
AbstractUnwindCursor *co = (AbstractUnwindCursor *)cursor;
return co->step();
}
-
+_LIBUNWIND_WEAK_ALIAS(__unw_step, unw_step)
/// Get unwind info at cursor position in stack frame.
-_LIBUNWIND_EXPORT int unw_get_proc_info(unw_cursor_t *cursor,
- unw_proc_info_t *info) {
- _LIBUNWIND_TRACE_API("unw_get_proc_info(cursor=%p, &info=%p)",
+_LIBUNWIND_HIDDEN int __unw_get_proc_info(unw_cursor_t *cursor,
+ unw_proc_info_t *info) {
+ _LIBUNWIND_TRACE_API("__unw_get_proc_info(cursor=%p, &info=%p)",
static_cast<void *>(cursor), static_cast<void *>(info));
AbstractUnwindCursor *co = (AbstractUnwindCursor *)cursor;
co->getInfo(info);
@@ -176,21 +174,21 @@
else
return UNW_ESUCCESS;
}
-
+_LIBUNWIND_WEAK_ALIAS(__unw_get_proc_info, unw_get_proc_info)
/// Resume execution at cursor position (aka longjump).
-_LIBUNWIND_EXPORT int unw_resume(unw_cursor_t *cursor) {
- _LIBUNWIND_TRACE_API("unw_resume(cursor=%p)", static_cast<void *>(cursor));
+_LIBUNWIND_HIDDEN int __unw_resume(unw_cursor_t *cursor) {
+ _LIBUNWIND_TRACE_API("__unw_resume(cursor=%p)", static_cast<void *>(cursor));
AbstractUnwindCursor *co = (AbstractUnwindCursor *)cursor;
co->jumpto();
return UNW_EUNSPEC;
}
-
+_LIBUNWIND_WEAK_ALIAS(__unw_resume, unw_resume)
/// Get name of function at cursor position in stack frame.
-_LIBUNWIND_EXPORT int unw_get_proc_name(unw_cursor_t *cursor, char *buf,
- size_t bufLen, unw_word_t *offset) {
- _LIBUNWIND_TRACE_API("unw_get_proc_name(cursor=%p, &buf=%p, bufLen=%lu)",
+_LIBUNWIND_HIDDEN int __unw_get_proc_name(unw_cursor_t *cursor, char *buf,
+ size_t bufLen, unw_word_t *offset) {
+ _LIBUNWIND_TRACE_API("__unw_get_proc_name(cursor=%p, &buf=%p, bufLen=%lu)",
static_cast<void *>(cursor), static_cast<void *>(buf),
static_cast<unsigned long>(bufLen));
AbstractUnwindCursor *co = (AbstractUnwindCursor *)cursor;
@@ -199,58 +197,62 @@
else
return UNW_EUNSPEC;
}
-
+_LIBUNWIND_WEAK_ALIAS(__unw_get_proc_name, unw_get_proc_name)
/// Checks if a register is a floating-point register.
-_LIBUNWIND_EXPORT int unw_is_fpreg(unw_cursor_t *cursor, unw_regnum_t regNum) {
- _LIBUNWIND_TRACE_API("unw_is_fpreg(cursor=%p, regNum=%d)",
+_LIBUNWIND_HIDDEN int __unw_is_fpreg(unw_cursor_t *cursor,
+ unw_regnum_t regNum) {
+ _LIBUNWIND_TRACE_API("__unw_is_fpreg(cursor=%p, regNum=%d)",
static_cast<void *>(cursor), regNum);
AbstractUnwindCursor *co = (AbstractUnwindCursor *)cursor;
return co->validFloatReg(regNum);
}
-
+_LIBUNWIND_WEAK_ALIAS(__unw_is_fpreg, unw_is_fpreg)
/// Checks if a register is a floating-point register.
-_LIBUNWIND_EXPORT const char *unw_regname(unw_cursor_t *cursor,
- unw_regnum_t regNum) {
- _LIBUNWIND_TRACE_API("unw_regname(cursor=%p, regNum=%d)",
+_LIBUNWIND_HIDDEN const char *__unw_regname(unw_cursor_t *cursor,
+ unw_regnum_t regNum) {
+ _LIBUNWIND_TRACE_API("__unw_regname(cursor=%p, regNum=%d)",
static_cast<void *>(cursor), regNum);
AbstractUnwindCursor *co = (AbstractUnwindCursor *)cursor;
return co->getRegisterName(regNum);
}
-
+_LIBUNWIND_WEAK_ALIAS(__unw_regname, unw_regname)
/// Checks if current frame is signal trampoline.
-_LIBUNWIND_EXPORT int unw_is_signal_frame(unw_cursor_t *cursor) {
- _LIBUNWIND_TRACE_API("unw_is_signal_frame(cursor=%p)",
+_LIBUNWIND_HIDDEN int __unw_is_signal_frame(unw_cursor_t *cursor) {
+ _LIBUNWIND_TRACE_API("__unw_is_signal_frame(cursor=%p)",
static_cast<void *>(cursor));
AbstractUnwindCursor *co = (AbstractUnwindCursor *)cursor;
return co->isSignalFrame();
}
+_LIBUNWIND_WEAK_ALIAS(__unw_is_signal_frame, unw_is_signal_frame)
#ifdef __arm__
// Save VFP registers d0-d15 using FSTMIADX instead of FSTMIADD
-_LIBUNWIND_EXPORT void unw_save_vfp_as_X(unw_cursor_t *cursor) {
- _LIBUNWIND_TRACE_API("unw_fpreg_save_vfp_as_X(cursor=%p)",
+_LIBUNWIND_HIDDEN void __unw_save_vfp_as_X(unw_cursor_t *cursor) {
+ _LIBUNWIND_TRACE_API("__unw_get_fpreg_save_vfp_as_X(cursor=%p)",
static_cast<void *>(cursor));
AbstractUnwindCursor *co = (AbstractUnwindCursor *)cursor;
return co->saveVFPAsX();
}
+_LIBUNWIND_WEAK_ALIAS(__unw_save_vfp_as_X, unw_save_cfp_as_X)
#endif
#if defined(_LIBUNWIND_SUPPORT_DWARF_UNWIND)
/// SPI: walks cached DWARF entries
-_LIBUNWIND_EXPORT void unw_iterate_dwarf_unwind_cache(void (*func)(
+_LIBUNWIND_HIDDEN void __unw_iterate_dwarf_unwind_cache(void (*func)(
unw_word_t ip_start, unw_word_t ip_end, unw_word_t fde, unw_word_t mh)) {
- _LIBUNWIND_TRACE_API("unw_iterate_dwarf_unwind_cache(func=%p)",
+ _LIBUNWIND_TRACE_API("__unw_iterate_dwarf_unwind_cache(func=%p)",
reinterpret_cast<void *>(func));
DwarfFDECache<LocalAddressSpace>::iterateCacheEntries(func);
}
-
+_LIBUNWIND_WEAK_ALIAS(__unw_iterate_dwarf_unwind_cache,
+ unw_iterate_dwarf_unwind_cache)
/// IPI: for __register_frame()
-void _unw_add_dynamic_fde(unw_word_t fde) {
+void __unw_add_dynamic_fde(unw_word_t fde) {
CFI_Parser<LocalAddressSpace>::FDE_Info fdeInfo;
CFI_Parser<LocalAddressSpace>::CIE_Info cieInfo;
const char *message = CFI_Parser<LocalAddressSpace>::decodeFDE(
@@ -264,12 +266,12 @@
fdeInfo.pcStart, fdeInfo.pcEnd,
fdeInfo.fdeStart);
} else {
- _LIBUNWIND_DEBUG_LOG("_unw_add_dynamic_fde: bad fde: %s", message);
+ _LIBUNWIND_DEBUG_LOG("__unw_add_dynamic_fde: bad fde: %s", message);
}
}
/// IPI: for __deregister_frame()
-void _unw_remove_dynamic_fde(unw_word_t fde) {
+void __unw_remove_dynamic_fde(unw_word_t fde) {
// fde is own mh_group
DwarfFDECache<LocalAddressSpace>::removeAllIn((LocalAddressSpace::pint_t)fde);
}