bjoernager/rust
bjoernager/rust
1
Fork 0
Code Activity

auto merge of #10013 : bdash/rust/mavericks-unwinding, r=alexcrichton

Browse source 
OS X 10.9's linker has a bug that results in it failing to preserve
DWARF unwind information when passed the -no_compact_unwind flag.
This flag is passed on OS X because the unwind information for
__morestack cannot be represented by the compact unwind format.

We can work around this problem by using a more targeted approach
to disabling compact unwind information. The OS X linker looks for
a particular pattern in the DWARF unwind information and will not
attempt to convert the unwind information to the compact format.
The pattern in question is the return address register being saved
twice to the same location.

Fixes #6849.
This commit is contained in:
bors 2013-10-22 13:46:25 -07:00
commit b477f7a7b7
4 changed files with 23 additions and 13 deletions
Download patch file Download diff file Expand all files Collapse all files

4
mk/platform.mk
View file

@ -204,7 +204,7 @@ CFG_LIB_GLOB_x86_64-apple-darwin=lib$(1)-*.dylib
CFG_LIB_DSYM_GLOB_x86_64-apple-darwin=lib$(1)-*.dylib.dSYM CFG_LIB_DSYM_GLOB_x86_64-apple-darwin=lib$(1)-*.dylib.dSYM
CFG_GCCISH_CFLAGS_x86_64-apple-darwin := -Wall -Werror -g -fPIC -m64 -arch x86_64 CFG_GCCISH_CFLAGS_x86_64-apple-darwin := -Wall -Werror -g -fPIC -m64 -arch x86_64
CFG_GCCISH_CXXFLAGS_x86_64-apple-darwin := -fno-rtti CFG_GCCISH_CXXFLAGS_x86_64-apple-darwin := -fno-rtti
CFG_GCCISH_LINK_FLAGS_x86_64-apple-darwin := -dynamiclib -pthread -framework CoreServices -Wl,-no_compact_unwind -m64 CFG_GCCISH_LINK_FLAGS_x86_64-apple-darwin := -dynamiclib -pthread -framework CoreServices -m64
CFG_GCCISH_DEF_FLAG_x86_64-apple-darwin := -Wl,-exported_symbols_list, CFG_GCCISH_DEF_FLAG_x86_64-apple-darwin := -Wl,-exported_symbols_list,
CFG_GCCISH_PRE_LIB_FLAGS_x86_64-apple-darwin := CFG_GCCISH_PRE_LIB_FLAGS_x86_64-apple-darwin :=
CFG_GCCISH_POST_LIB_FLAGS_x86_64-apple-darwin := CFG_GCCISH_POST_LIB_FLAGS_x86_64-apple-darwin :=
@ -230,7 +230,7 @@ CFG_LIB_GLOB_i686-apple-darwin=lib$(1)-*.dylib
CFG_LIB_DSYM_GLOB_i686-apple-darwin=lib$(1)-*.dylib.dSYM CFG_LIB_DSYM_GLOB_i686-apple-darwin=lib$(1)-*.dylib.dSYM
CFG_GCCISH_CFLAGS_i686-apple-darwin := -Wall -Werror -g -fPIC -m32 -arch i386 CFG_GCCISH_CFLAGS_i686-apple-darwin := -Wall -Werror -g -fPIC -m32 -arch i386
CFG_GCCISH_CXXFLAGS_i686-apple-darwin := -fno-rtti CFG_GCCISH_CXXFLAGS_i686-apple-darwin := -fno-rtti
CFG_GCCISH_LINK_FLAGS_i686-apple-darwin := -dynamiclib -pthread -framework CoreServices -Wl,-no_compact_unwind -m32 CFG_GCCISH_LINK_FLAGS_i686-apple-darwin := -dynamiclib -pthread -framework CoreServices -m32
CFG_GCCISH_DEF_FLAG_i686-apple-darwin := -Wl,-exported_symbols_list, CFG_GCCISH_DEF_FLAG_i686-apple-darwin := -Wl,-exported_symbols_list,
CFG_GCCISH_PRE_LIB_FLAGS_i686-apple-darwin := CFG_GCCISH_PRE_LIB_FLAGS_i686-apple-darwin :=
CFG_GCCISH_POST_LIB_FLAGS_i686-apple-darwin := CFG_GCCISH_POST_LIB_FLAGS_i686-apple-darwin :=

8
src/librustc/back/link.rs
View file

@ -1112,14 +1112,6 @@ pub fn link_args(sess: Session,
~"-Wl,-rpath,/usr/local/lib/gcc44"]); ~"-Wl,-rpath,/usr/local/lib/gcc44"]);
} }
// OS X 10.6 introduced 'compact unwind info', which is produced by the
// linker from the dwarf unwind info. Unfortunately, it does not seem to
// understand how to unwind our __morestack frame, so we have to turn it
// off. This has impacted some other projects like GHC.
if sess.targ_cfg.os == session::OsMacos {
args.push(~"-Wl,-no_compact_unwind");
}
// Stack growth requires statically linking a __morestack function // Stack growth requires statically linking a __morestack function
args.push(~"-lmorestack"); args.push(~"-lmorestack");

15
src/rt/arch/i386/morestack.S
View file

@ -62,9 +62,9 @@
is that OS X 10.6+ uses its own 'compact unwind info', is that OS X 10.6+ uses its own 'compact unwind info',
an undocumented format generated by the linker from an undocumented format generated by the linker from
the DWARF CFI. This compact unwind info doesn't correctly the DWARF CFI. This compact unwind info doesn't correctly
capture the nuance of the __morestack frame, and as a capture the nuance of the __morestack frame, so we need to
result all of our linking on OS X uses the -no_compact_unwind prevent the linker from attempting to convert its DWARF unwind
flag. information.
*/ */
.text .text
@ -118,6 +118,15 @@ MORESTACK:
// FIXME(#9854) these cfi directives don't work on windows. // FIXME(#9854) these cfi directives don't work on windows.
pushl %ebp pushl %ebp
#if defined(__APPLE__)
// The pattern of the return address being saved twice to the same location
// tells the OS X linker that it should not attempt to convert the DWARF
// unwind information to the compact format.
.cfi_offset %eip, -4
.cfi_offset %eip, -4
#endif
// The CFA is 20 bytes above the register that it is // The CFA is 20 bytes above the register that it is
// associated with for this frame (which will be %ebp) // associated with for this frame (which will be %ebp)
.cfi_def_cfa_offset 20 .cfi_def_cfa_offset 20

9
src/rt/arch/x86_64/morestack.S
View file

@ -43,6 +43,15 @@ MORESTACK:
// bytes greater than a normal frame, to allow the unwinder // bytes greater than a normal frame, to allow the unwinder
// to skip the partial frame of the original function. // to skip the partial frame of the original function.
.cfi_def_cfa_offset 24 .cfi_def_cfa_offset 24
#if defined(__APPLE__)
// The pattern of the return address being saved twice to the same location
// tells the OS X linker that it should not attempt to convert the DWARF
// unwind information to the compact format.
.cfi_offset %rip, -8
.cfi_offset %rip, -8
#endif
// %rbp is -24 bytes from the CFA // %rbp is -24 bytes from the CFA
.cfi_offset %rbp, -24 .cfi_offset %rbp, -24
movq %rsp, %rbp movq %rsp, %rbp