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libgcc: Make heap trampoline support dynamic [PR113403].

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In order to handle system security constraints during GCC build
and test and that most platform versions cannot link to libgcc_eh
since the unwinder there is incompatible with the system one.

1. We make the support functions weak definitions.
2. We include them as a CRT for platform conditions that do not
   allow libgcc_eh.
3. We ensure that the weak symbols are exported from DSOs (which
   includes exes on Darwin) so that the dynamic linker will
   pick one instance (which avoids duplication of trampoline
   caches).

	PR libgcc/113403

gcc/ChangeLog:

	* config/darwin.h (DARWIN_SHARED_WEAK_ADDS, DARWIN_WEAK_CRTS): New.
	(REAL_LIBGCC_SPEC): Move weak CRT handling to separate spec.
	* config/i386/darwin.h (DARWIN_HEAP_T_LIB): New.
	* config/i386/darwin32-biarch.h (DARWIN_HEAP_T_LIB): New.
	* config/i386/darwin64-biarch.h (DARWIN_HEAP_T_LIB): New.
	* config/rs6000/darwin.h (DARWIN_HEAP_T_LIB): New.

libgcc/ChangeLog:

	* config.host: Build libheap_t.a for i686/x86_64 Darwin.
	* config/aarch64/heap-trampoline.c (HEAP_T_ATTR): New.
	(allocate_tramp_ctrl): Allow a target to build this as a weak def.
	(__gcc_nested_func_ptr_created): Likewise.
	* config/i386/heap-trampoline.c (HEAP_T_ATTR): New.
	(allocate_tramp_ctrl): Allow a target to build this as a weak def.
	(__gcc_nested_func_ptr_created): Likewise.
	* config/t-darwin: Build libheap_t.a (a CRT with heap trampoline
	support).
This commit is contained in:
Iain Sandoe 2024-01-28 13:31:56 +00:00
parent 7b3b3788c5
commit 506e74f53a
9 changed files with 72 additions and 18 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

43
gcc/config/darwin.h
View file

@ -314,13 +314,17 @@ extern GTY(()) int darwin_ms_struct;
# define DARWIN_RPATH_LINK \
"%{!r:%{!nostdlib:%{!nodefaultrpaths:%(darwin_rpaths)}}}"
# define DARWIN_SHARED_LIBGCC "-lgcc_s.1.1"
# define DARWIN_SHARED_WEAK_ADDS " "
#else
# define DARWIN_RPATH_LINK ""
# define DARWIN_SHARED_LIBGCC \
"%:version-compare(!> 10.11 mmacosx-version-min= -lgcc_s.1.1) \
%:version-compare(>= 10.11 mmacosx-version-min= -lemutls_w) "
"%:version-compare(!> 10.11 mmacosx-version-min= -lgcc_s.1.1)"
# define DARWIN_SHARED_WEAK_ADDS \
"%{%:version-compare(>= 10.11 mmacosx-version-min= -lemutls_w): \
" DARWIN_HEAP_T_LIB "}"
#endif
/* We might elect to add a path even when this compiler does not use embedded
run paths, so that we can use libraries from an alternate compiler that is
using embedded runpaths. */
@ -398,7 +402,9 @@ extern GTY(()) int darwin_ms_struct;
%{e*} %{r} \
%{o*}%{!o:-o a.out} \
%{!r:%{!nostdlib:%{!nostartfiles:%S}}} \
%{L*} %(link_libgcc) %o \
%{L*} %(link_libgcc) \
%{!r:%{!nostdlib:%{!nodefaultlibs: " DARWIN_WEAK_CRTS "}}} \
%o \
%{!r:%{!nostdlib:%{!nodefaultlibs:\
%{fprofile-arcs|fprofile-generate*|coverage:-lgcov} \
%{fopenacc|fopenmp|%:gt(%{ftree-parallelize-loops=*:%*} 1): \
@ -412,15 +418,15 @@ extern GTY(()) int darwin_ms_struct;
%(link_ssp) \
%:version-compare(>< 10.6 10.7 mmacosx-version-min= -ld10-uwfef) \
%(link_gcc_c_sequence) \
%{!nodefaultexport:%{dylib|dynamiclib|bundle: \
%:version-compare(>= 10.11 asm_macosx_version_min= -U) \
%:version-compare(>= 10.11 asm_macosx_version_min= ___emutls_get_address) \
%:version-compare(>= 10.11 asm_macosx_version_min= -exported_symbol) \
%:version-compare(>= 10.11 asm_macosx_version_min= ___emutls_get_address) \
%:version-compare(>= 10.11 asm_macosx_version_min= -U) \
%:version-compare(>= 10.11 asm_macosx_version_min= ___emutls_register_common) \
%:version-compare(>= 10.11 asm_macosx_version_min= -exported_symbol) \
%:version-compare(>= 10.11 asm_macosx_version_min= ___emutls_register_common) \
%{!nodefaultexport: \
%{%:version-compare(>= 10.11 asm_macosx_version_min= -U): \
___emutls_get_address -exported_symbol ___emutls_get_address \
-U ___emutls_register_common \
-exported_symbol ___emutls_register_common \
-U ___gcc_nested_func_ptr_created \
-exported_symbol ___gcc_nested_func_ptr_created \
-U ___gcc_nested_func_ptr_deleted \
-exported_symbol ___gcc_nested_func_ptr_deleted \
}} \
}}}\
%{!r:%{!nostdlib:%{!nostartfiles:%E}}} %{T*} %{F*} "\
@ -542,16 +548,21 @@ extern GTY(()) int darwin_ms_struct;
#undef REAL_LIBGCC_SPEC
#define REAL_LIBGCC_SPEC \
"%{static-libgcc|static: \
%:version-compare(!> 10.6 mmacosx-version-min= -lgcc_eh) \
%:version-compare(>= 10.6 mmacosx-version-min= -lemutls_w); \
%:version-compare(!> 10.6 mmacosx-version-min= -lgcc_eh); \
shared-libgcc|fexceptions|fobjc-exceptions|fgnu-runtime: \
" DARWIN_SHARED_LIBGCC " \
%:version-compare(!> 10.3.9 mmacosx-version-min= -lgcc_eh) \
%:version-compare(>< 10.3.9 10.5 mmacosx-version-min= -lgcc_s.10.4) \
%:version-compare(>< 10.5 10.6 mmacosx-version-min= -lgcc_s.10.5); \
: -lemutls_w \
%:version-compare(>< 10.5 10.6 mmacosx-version-min= -lgcc_s.10.5) \
} -lgcc "
#define DARWIN_WEAK_CRTS \
"%{static-libgcc|static: \
%{%:version-compare(>= 10.6 mmacosx-version-min= -lemutls_w): \
" DARWIN_HEAP_T_LIB "} ; \
: -lemutls_w " DARWIN_HEAP_T_LIB " \
}"
/* We specify crt0.o as -lcrt0.o so that ld will search the library path. */
#undef STARTFILE_SPEC

2
gcc/config/i386/darwin.h
View file

@ -119,6 +119,8 @@ along with GCC; see the file COPYING3. If not see
/* We default to x86_64 for single-arch builds, bi-arch overrides. */
#define DARWIN_ARCH_SPEC "x86_64"
#define DARWIN_SUBARCH_SPEC DARWIN_ARCH_SPEC
#undef DARWIN_HEAP_T_LIB
#define DARWIN_HEAP_T_LIB " -lheapt_w "
#endif
#undef SUBTARGET_EXTRA_SPECS

3
gcc/config/i386/darwin32-biarch.h
View file

@ -27,6 +27,9 @@ along with GCC; see the file COPYING3. If not see
#undef DARWIN_SUBARCH_SPEC
#define DARWIN_SUBARCH_SPEC DARWIN_ARCH_SPEC
#undef DARWIN_HEAP_T_LIB
#define DARWIN_HEAP_T_LIB " %{m64:-lheapt_w}"
#undef SUBTARGET_EXTRA_SPECS
#define SUBTARGET_EXTRA_SPECS \
DARWIN_EXTRA_SPECS \

3
gcc/config/i386/darwin64-biarch.h
View file

@ -28,6 +28,9 @@ along with GCC; see the file COPYING3. If not see
#undef DARWIN_SUBARCH_SPEC
#define DARWIN_SUBARCH_SPEC DARWIN_ARCH_SPEC
#undef DARWIN_HEAP_T_LIB
#define DARWIN_HEAP_T_LIB "%{!m32:-lheapt_w}"
#undef SUBTARGET_EXTRA_SPECS
#define SUBTARGET_EXTRA_SPECS \
DARWIN_EXTRA_SPECS \

3
gcc/config/rs6000/darwin.h
View file

@ -113,6 +113,9 @@
-lSystem \
}"
#undef DARWIN_HEAP_T_LIB
#define DARWIN_HEAP_T_LIB " "
/* We want -fPIC by default, unless we're using -static to compile for
the kernel or some such. The "-faltivec" option should have been
called "-maltivec" all along. */

7
libgcc/config.host
View file

@ -715,12 +715,15 @@ hppa*-*-netbsd*)
i[34567]86-*-darwin*)
tmake_file="$tmake_file i386/t-crtpc t-crtfm i386/t-msabi"
tm_file="$tm_file i386/darwin-lib.h"
extra_parts="$extra_parts crtprec32.o crtprec64.o crtprec80.o crtfastmath.o"
extra_parts="$extra_parts crtprec32.o crtprec64.o crtprec80.o"
extra_parts="$extra_parts crtfastmath.o libheapt_w.a"
tmake_file="${tmake_file} i386/t-heap-trampoline"
;;
x86_64-*-darwin*)
tmake_file="$tmake_file i386/t-crtpc t-crtfm i386/t-msabi"
tm_file="$tm_file i386/darwin-lib.h"
extra_parts="$extra_parts crtprec32.o crtprec64.o crtprec80.o crtfastmath.o"
extra_parts="$extra_parts crtprec32.o crtprec64.o crtprec80.o"
extra_parts="$extra_parts crtfastmath.o libheapt_w.a"
tmake_file="${tmake_file} i386/t-heap-trampoline"
;;
i[34567]86-*-elfiamcu)

8
libgcc/config/aarch64/heap-trampoline.c
View file

@ -15,6 +15,12 @@
#include <pthread.h>
#endif
/* HEAP_T_ATTR is provided to allow targets to build the exported functions
as weak definitions. */
#ifndef HEAP_T_ATTR
# define HEAP_T_ATTR
#endif
void *allocate_trampoline_page (void);
int get_trampolines_per_page (void);
struct tramp_ctrl_data *allocate_tramp_ctrl (struct tramp_ctrl_data *parent);
@ -107,6 +113,7 @@ allocate_tramp_ctrl (struct tramp_ctrl_data *parent)
return p;
}
HEAP_T_ATTR
void
__gcc_nested_func_ptr_created (void *chain, void *func, void **dst)
{
@ -154,6 +161,7 @@ __gcc_nested_func_ptr_created (void *chain, void *func, void **dst)
*dst = &trampoline->insns;
}
HEAP_T_ATTR
void
__gcc_nested_func_ptr_deleted (void)
{

8
libgcc/config/i386/heap-trampoline.c
View file

@ -15,6 +15,12 @@
#include <pthread.h>
#endif
/* HEAP_T_ATTR is provided to allow targets to build the exported functions
as weak definitions. */
#ifndef HEAP_T_ATTR
# define HEAP_T_ATTR
#endif
void *allocate_trampoline_page (void);
int get_trampolines_per_page (void);
struct tramp_ctrl_data *allocate_tramp_ctrl (struct tramp_ctrl_data *parent);
@ -107,6 +113,7 @@ allocate_tramp_ctrl (struct tramp_ctrl_data *parent)
return p;
}
HEAP_T_ATTR
void
__gcc_nested_func_ptr_created (void *chain, void *func, void **dst)
{
@ -154,6 +161,7 @@ __gcc_nested_func_ptr_created (void *chain, void *func, void **dst)
*dst = &trampoline->insns;
}
HEAP_T_ATTR
void
__gcc_nested_func_ptr_deleted (void)
{

13
libgcc/config/t-darwin
View file

@ -51,5 +51,18 @@ LIB2ADDEH = $(srcdir)/unwind-dw2.c \
# Do not build a shared unwind lib by default.
LIBEHSOBJS=
# Make heap trampoline helpers weak definitions so that we can merge them from
# multiple DSOs.
heap-trampoline.o: HOST_LIBGCC2_CFLAGS += \
-DHEAP_T_ATTR='__attribute__((__weak__,__visibility__("default")))'
heap-trampoline_s.o: HOST_LIBGCC2_CFLAGS += \
-DHEAP_T_ATTR='__attribute__((__weak__,__visibility__("default")))'
# Make a heap trampoline support CRT so that it can be linked optionally, use
# the shared version so that we can link with DSOs.
libheapt_w.a: heap-trampoline_s.o
$(AR_CREATE_FOR_TARGET) $@ $<
$(RANLIB_FOR_TARGET) $@
# Symbols for all the sub-ports.
SHLIB_MAPFILES = libgcc-std.ver $(srcdir)/config/libgcc-libsystem.ver