member of RTDyldMemoryManager (and rename to getSymbolAddressInProcess).
The functionality this provides is very specific to RTDyldMemoryManager, so it
makes sense to keep it in that class to avoid accidental re-use.
No functional change.
llvm-svn: 218741
The contract of this function seems problematic (fallback in either
direction seems like it could produce bugs in one client or another),
but here's some tests for its current behavior, at least. See the
commit/review thread of r218187 for more discussion.
llvm-svn: 218626
This patch modifies RTDyldMemoryManager::getSymbolAddress(Name)'s behavior to
make it consistent with how clients are using it: Name should be mangled, and
getSymbolAddress should demangle it on the caller's behalf before looking the
name up in the process. This patch also fixes the one client
(MCJIT::getPointerToFunction) that had been passing unmangled names (by having
it pass mangled names instead).
Background:
RTDyldMemoryManager::getSymbolAddress(Name) has always used a re-try mechanism
when looking up symbol names in the current process. Prior to this patch
getSymbolAddress first tried to look up 'Name' exactly as the user passed it in
and then, if that failed, tried to demangle 'Name' and re-try the look up. The
implication of this behavior is that getSymbolAddress expected to be called with
unmangled names, and that handling mangled names was a fallback for convenience.
This is inconsistent with how clients (particularly the RuntimeDyldImpl
subclasses, but also MCJIT) usually use this API. Most clients pass in mangled
names, and succeed only because of the fallback case. For clients passing in
mangled names, getSymbolAddress's old behavior was actually dangerous, as it
could cause unmangled names in the process to shadow mangled names being looked
up.
For example, consider:
foo.c:
int _x = 7;
int x() { return _x; }
foo.o:
000000000000000c D __x
0000000000000000 T _x
If foo.c becomes part of the process (E.g. via dlopen("libfoo.dylib")) it will
add symbols 'x' (the function) and '_x' (the variable) to the process. However
jit clients looking for the function 'x' will be using the mangled function name
'_x' (note how function 'x' appears in foo.o). When getSymbolAddress goes
looking for '_x' it will find the variable instead, and return its address and
in place of the function, leading to JIT'd code calling the variable and
crashing (if we're lucky).
By requiring that getSymbolAddress be called with mangled names, and demangling
only when we're about to do a lookup in the process, the new behavior
implemented in this patch should eliminate any chance of names being shadowed
during lookup.
There's no good way to test this at the moment: This issue only arrises when
looking up process symbols (not JIT'd symbols). Any test case would have to
generate a platform-appropriate dylib to pass to llvm-rtdyld, and I'm not
aware of any in-tree tool for doing this in a portable way.
llvm-svn: 218187
subsequent changes are easier to review. About to fix some layering
issues, and wanted to separate out the necessary churn.
Also comment and sink the include of "Windows.h" in three .inc files to
match the usage in Memory.inc.
llvm-svn: 198685
Tests to follow.
PIC with small code model and EH frame handling will not work with multiple modules. There are also some rough edges to be smoothed out for remote target support.
llvm-svn: 191722
libExecutionEngine. Move method implementations that aren't specific to
allocation out of SectionMemoryManager and into RTDyldMemoryManager.
This is in preparation for exposing RTDyldMemoryManager through the C
API.
This is a fixed version of r182407 and r182411. That first revision
broke builds because I forgot to move the conditional includes of
various POSIX headers from SectionMemoryManager into
RTDyldMemoryManager. Those includes are necessary because of how
getPointerToNamedFunction works around the glibc libc_nonshared.a thing.
The latter revision still broke things because I forgot to include
llvm/Config/config.h.
llvm-svn: 182418
libExecutionEngine. Move method implementations that aren't specific to
allocation out of SectionMemoryManager and into RTDyldMemoryManager.
This is in preparation for exposing RTDyldMemoryManager through the C
API.
This is a fixed version of r182407. That revision broke builds because I
forgot to move the conditional includes of various POSIX headers from
SectionMemoryManager into RTDyldMemoryManager. Those includes are
necessary because of how getPointerToNamedFunction works around the
glibc libc_nonshared.a thing.
llvm-svn: 182411
libExecutionEngine. Move method implementations that aren't specific to
allocation out of SectionMemoryManager and into RTDyldMemoryManager.
This is in preparation for exposing RTDyldMemoryManager through the C
API.
llvm-svn: 182407
