Just like x86 exception handler table, the table for x64 needs to be sorted
so that runtime can binary search on it. Unlike x86, the table entry for x64
has multiple fields, and they need to be sorted according to its BeginAddress
field. This patch also fixes a bug in relocations.
llvm-svn: 202874
It looks like the contents of the table need to be sorted according to its
value, so that the runtime can find the entry by binary search. I'm not 100%
sure if we really have to do that, but at least I can say it's safe to do
because the contents of .sxdata is just a list of exception handlers' RVAs.
llvm-svn: 202550
If all input files are compatible with Structured Exception Handling, linker
is supposed to create an exectuable with a table for SEH handlers. The table
consists of exception handlers entry point addresses.
The basic idea of SEH in x86 Microsoft ABI is to list all valid entry points
of exception handlers in an read-only memory, so that an attacker cannot
override the addresses in it. In x86 ABI, data for exception handling is mostly
on stack, so it's volnerable to stack overflow attack. In order to protect
against it, Windows runtime uses the table to check a return address, to
ensure that the address is really an valid entry point for an exception handler.
Compiler emits a list of exception handler functions to .sxdata section. It
also emits a marker symbol "@feat.00" to indicate that the object is compatible
with SEH. SEH is a relatively new feature for COFF, and mixing SEH-compatible
and SEH-incompatible objects will result in an invalid executable, so is the
marker.
If all input files are compatible with SEH, LLD emits a SEH table. SEH table
needs to be pointed by Load Configuration strucutre, so when emitting a SEH
table LLD emits it too. The address of a Load Configuration will be stored to
the file header.
llvm-svn: 202248
target_link_libraries(INTERFACE) doesn't bring inter-target dependencies in add_library,
although final targets have dependencies to whole dependent libraries.
It makes most libraries can be built in parallel.
target_link_libraries(PRIVATE) is used to shaared library.
Each dependent library is linked to the target.so, and its user will not see its grandchildren.
For example,
- libclang.so has sufficient libclang*.a(s).
- c-index-test requires just only libclang.so.
FIXME: lld is tweaked minimally. Adding INTERFACE in each library would be better thing.
llvm-svn: 202241
This restores the debug output to how it was before r197727 broke it. This
went undetected because the corresponding test was never run due to broken
feature detection.
llvm-svn: 202079
Syntactically /SAFESEH is a boolean flag -- you can pass /SAFESEH or /SAFESEH:no.
The meaning of /SAFESEH is as follows.
- If /SAFESEH is specified, the linker will produce an executable with SEH table.
If any input files are not compatible with SEH, it's an error.
- If /SAFESEH:no is specified, the linker will not emit SEH table even if all
input files are compatible with SEH.
- If no option is specified, the linker emits SEH table if all input files are
compatible with SEH.
llvm-svn: 201895
The sections .rela/.rel.(*) have a alignment of 2 in the final image created by
the linker. This needs to be properly set to the right alignment depending on
the architecture(32/64bits).
llvm-svn: 201740
The target machine type affects the meaning of other options, in particular
how to mangle symbols. So we want to handle the option first and then parse
all the other options.
llvm-svn: 200589
Rui Ueyama