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authorFrederic Konrad <konrad@adacore.com>2020-11-05 11:34:57 +0100
committerOlivier Hainque <hainque@adacore.com>2021-12-13 18:03:03 +0000
commit4099d6501e3526ca8d1d01e904f42b83c6824674 (patch)
treede1958f3de2156933e67882c59efcbc38d2ec928 /libgcc
parent0515c95d5fe0a865f688f3ab89572b917e8f0185 (diff)
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Tigthen libc_internal and crtstuff for VxWorks shared objects
This change tightens and documents the use of libc_internal, then strengthens the VxWorks crtstuff objects for the support of shared libraries. In particular: - Define __dso_handle, which libstdc++.so requires, - Provide _init and _fini functions to run through the init/fini arrays for shared libs in configurations which HAVE_INITFINI_ARRAY_SUPPORT. The init/fini functions are provided by libc_internal.a for static links but with slightly different names and we don't want to risk dragging other libc_internal contents in the closure accidentally so make sure we don't link with it. As for the !vxworks crtstuff, the new shared libs specific bits are conditioned by a CRTSTUFFS_O macro, for which we provide new Makefile fragment. The bits to actually use the fragment and the shared objects will be added by a forthcoming change, as part of a more general configury update for shared libs. The change also adds guards the eh table registration code in vxcrtstuff so the objects can be used for either init/fini or eh tables independently. 2021-12-07 Fred Konrad <konrad@adacore.com> Olivier Hainque <hainque@adacore.com> gcc/ * config/vxworks.h (VXWORKS_BASE_LIBS_RTP): Guard -lc_internal on !shared+!non-static and document. (VXWORKS_LIB_SPEC): Remove the bits intended to drag the init/fini functions from libc_internal in the shared lib case. (VX_CRTBEGIN_SPEC/VX_CRTEND_SPEC): Use vxcrtstuff objects also in configurations with shared lib and INITFINI_ARRAY support. libgcc/ * config/t-vxcrtstuffS: New Makefile fragment. * config/vxcrtstuff.c: Provide __dso_handle. Provide _init/_fini functions for INITFINI_ARRAY support in shared libs and guard the definition of eh table registration functions on conditions indicating they are needed.
Diffstat (limited to 'libgcc')
-rw-r--r--libgcc/config/t-vxcrtstuffS9
-rw-r--r--libgcc/config/vxcrtstuff.c77
2 files changed, 81 insertions, 5 deletions
diff --git a/libgcc/config/t-vxcrtstuffS b/libgcc/config/t-vxcrtstuffS
new file mode 100644
index 0000000..6b65b00
--- /dev/null
+++ b/libgcc/config/t-vxcrtstuffS
@@ -0,0 +1,9 @@
+# Shared versions of vx_crt{begin,end}.o, those one must be compiled only
+# when the shared libraries are available
+
+vx_crtbeginS.o: $(srcdir)/config/vxcrtstuff.c
+ $(crt_compile) $(CRTSTUFF_T_CFLAGS_S) -DCRT_BEGIN -c $< -DCRTSTUFFS_O
+vx_crtendS.o: $(srcdir)/config/vxcrtstuff.c
+ $(crt_compile) $(CRTSTUFF_T_CFLAGS_S) -DCRT_END -c $< -DCRTSTUFFS_O
+
+EXTRA_PARTS += vx_crtbeginS.o vx_crtendS.o
diff --git a/libgcc/config/vxcrtstuff.c b/libgcc/config/vxcrtstuff.c
index c15e15e..80f51f7 100644
--- a/libgcc/config/vxcrtstuff.c
+++ b/libgcc/config/vxcrtstuff.c
@@ -50,15 +50,25 @@ see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
#define USE_CDTORS_SECTIONS
#endif
+#if DWARF2_UNWIND_INFO && !defined(__USING_SJLJ_EXCEPTIONS__)
+#define USE_EH_FRAME_REGISTRY
+#endif
+
/* ------------------------------ crtbegin ------------------------------- */
#ifdef CRT_BEGIN
-/* Stick a label at the beginning of the frame unwind info so we can register
- and deregister it with the exception handling library code. */
-static const char __EH_FRAME_BEGIN__[]
-__attribute__((section(__LIBGCC_EH_FRAME_SECTION_NAME__), aligned(4)))
- = { };
+#if DEFAULT_USE_CXA_ATEXIT && defined(__RTP__)
+/* This mimics the crtstuff.c behavior. dso_handle should be NULL for the
+ main program (in vx_crtbegin.o) and a unique value for the shared libraries
+ (in vx_crtbeginS.o). */
+extern void *__dso_handle __attribute__ ((__visibility__ ("hidden")));
+#ifdef CRTSTUFFS_O
+void *__dso_handle = &__dso_handle;
+#else
+void *__dso_handle = 0;
+#endif
+#endif /* DEFAULT_USE_CXA_ATEXIT */
/* Determine what names to use for the constructor/destructor functions. */
@@ -89,6 +99,53 @@ __attribute__((section(__LIBGCC_EH_FRAME_SECTION_NAME__), aligned(4)))
#define EH_CTOR_ATTRIBUTE __attribute__((constructor (101)))
#define EH_DTOR_ATTRIBUTE __attribute__((destructor (101)))
+/* Provide the init/fini array support functions for shared libraries,
+ where we don't want to drag libc_internal contents blindly and which
+ provides functions with a slightly different name anyway. */
+
+#if HAVE_INITFINI_ARRAY_SUPPORT && defined(CRTSTUFFS_O)
+
+/* Run through the .init_array, .fini_array sections. The linker script
+ *must* provide __init_array_start, __init_array_end, __fini_array_start,
+ __fini_array_end symbols. */
+
+typedef void (*initfini_ptr) (void);
+extern initfini_ptr __init_array_start[];
+extern initfini_ptr __init_array_end[];
+extern initfini_ptr __fini_array_start[];
+extern initfini_ptr __fini_array_end[];
+
+/* Provide the actual code through static functions, which don't need
+ to be exposed in the shared lib interface. */
+
+static void __exec_init_array(void)
+{
+ initfini_ptr *fn;
+ for (fn = __init_array_start; fn < __init_array_end; ++fn)
+ (*fn)();
+}
+
+static void __exec_fini_array(void)
+{
+ initfini_ptr *fn;
+ for (fn = __fini_array_end - 1; fn >= __fini_array_start; --fn)
+ (*fn)();
+}
+
+/* Reference the two above functions as the init / fini function. */
+
+void __attribute__ ((__section__ (".init"))) _init()
+{
+ __exec_init_array();
+}
+
+void __attribute__ ((__section__ (".fini"))) _fini()
+{
+ __exec_fini_array();
+}
+
+#endif /* __CRTSTUFFS_O__ */
+
#else /* !USE_INITFINI_ARRAY */
/* Note: Even in case of .ctors/.dtors sections, we can't use the attribute
@@ -100,6 +157,13 @@ __attribute__((section(__LIBGCC_EH_FRAME_SECTION_NAME__), aligned(4)))
#endif /* USE_INITFINI_ARRAY */
+#ifdef USE_EH_FRAME_REGISTRY
+/* Stick a label at the beginning of the frame unwind info so we can register
+ and deregister it with the exception handling library code. */
+static const char __EH_FRAME_BEGIN__[]
+__attribute__((section(__LIBGCC_EH_FRAME_SECTION_NAME__), aligned(4)))
+ = { };
+
EH_LINKAGE EH_CTOR_ATTRIBUTE void EH_CTOR_NAME (void)
{
static struct object object;
@@ -110,6 +174,7 @@ EH_LINKAGE EH_DTOR_ATTRIBUTE void EH_DTOR_NAME (void)
{
__deregister_frame_info (__EH_FRAME_BEGIN__);
}
+#endif /* USE_EH_FRAME_REGISTRY */
#ifdef USE_CDTORS_SECTIONS
/* As explained above, we need to manually build the sections here as the
@@ -126,6 +191,7 @@ static void (* volatile eh_registration_dtors[])()
#elif defined (CRT_END) /* ! CRT_BEGIN */
+#ifdef USE_EH_FRAME_REGISTRY
/* Terminate the frame unwind info section with a 4byte 0 as a sentinel;
this would be the 'length' field in a real FDE. */
@@ -133,6 +199,7 @@ static const char __FRAME_END__[]
__attribute__ ((used, section(__LIBGCC_EH_FRAME_SECTION_NAME__),
aligned(4)))
= { 0, 0, 0, 0 };
+#endif /* USE_EH_FRAME_REGISTRY */
#else /* ! CRT_BEGIN & ! CRT_END */