Summary:
Before this change, personality directives were not emitted
if there was no invoke left in the function (of course until
recently this also meant that we couldn't know what
the personality actually was). This patch forces personality directives
to still be emitted, unless it is known to be a noop in the absence of
invokes, or the user explicitly specified `nounwind` (and not
`uwtable`) on the function.
Reviewers: majnemer, rnk
Subscribers: rnk, llvm-commits
Differential Revision: http://reviews.llvm.org/D10884
llvm-svn: 242185
The outlined funclets call intrinsics which reference labels from the
LSDA. This situation can easily arise in small functions with a single
cleanup at -O0, where Clang marks a definition as nounwind, and then
WinEHPrepare "discovers" that the landingpad is dead by accident and
deletes it.
We now need to ask the LLVM IR Function for it's personality directly,
rather than going through MachineModuleInfo.
Fixes PR23892.
llvm-svn: 242063
Apparently this is important, otherwise _except_handler3 assumes that
the registration node is corrupted and ignores it.
Also fix a bug in WinEHPrepare where we would insert code after a
terminator instruction.
llvm-svn: 241877
Summary:
Initially, these intrinsics seemed like part of a family of "frame"
related intrinsics, but now I think that's more confusing than helpful.
Initially, the LangRef specified that this would create a new kind of
allocation that would be allocated at a fixed offset from the frame
pointer (EBP/RBP). We ended up dropping that design, and leaving the
stack frame layout alone.
These intrinsics are really about sharing local stack allocations, not
frame pointers. I intend to go further and add an `llvm.localaddress()`
intrinsic that returns whatever register (EBP, ESI, ESP, RBX) is being
used to address locals, which should not be confused with the frame
pointer.
Naming suggestions at this point are welcome, I'm happy to re-run sed.
Reviewers: majnemer, nicholas
Subscribers: llvm-commits
Differential Revision: http://reviews.llvm.org/D11011
llvm-svn: 241633
The incoming EBP value established by the runtime is actually a pointer
to the end of the EH registration object, and not the true parent
function frame pointer. Clang doesn't need llvm.x86.seh.exceptioninfo
anymore because we know that the exception info pointer is at a fixed
offset from this incoming EBP.
The llvm.x86.seh.recoverfp intrinsic takes an EBP value provided by the
EH runtime and returns a pointer that is usable with llvm.framerecover.
The llvm.x86.seh.restoreframe intrinsic is inserted by the 32-bit
specific preparation pass in blocks targetted by the EH runtime. It
re-establishes any physical registers used by the parent function to
address the stack, such as the frame, base, and stack pointers.
Neither of these intrinsics correctly handle stack realignment prologues
yet, but it's possible to add that later.
Reviewers: majnemer
Differential Revision: http://reviews.llvm.org/D10848
llvm-svn: 241125
We were putting them in the filter field, which is correct for 64-bit
but wrong for 32-bit.
Also switch the order of scope table entry emission so outermost entries
are emitted first, and fix an obvious state assignment bug.
llvm-svn: 239574
This intrinsic is like framerecover plus a load. It recovers the EH
registration stack allocation from the parent frame and loads the
exception information field out of it, giving back a pointer to an
EXCEPTION_POINTERS struct. It's designed for clang to use in SEH filter
expressions instead of accessing the EXCEPTION_POINTERS parameter that
is available on x64.
This required a minor change to MC to allow defining a label variable to
another absolute framerecover label variable.
llvm-svn: 239567
Use a "safeseh" string attribute to do this. You would think we chould
just accumulate the set of personalities like we do on dwarf, but this
fails to account for the LSDA-loading thunks we use for
__CxxFrameHandler3. Each of those needs to make it into .sxdata as well.
The string attribute seemed like the most straightforward approach.
llvm-svn: 239448
This gets all the handler info through to the asm printer and we can
look at the .xdata tables now. I've convinced one small catch-all test
case to work, but other than that, it would be a stretch to say this is
functional.
The state numbering algorithm avoids doing any scope reconstruction as
we do for C++ to simplify the implementation.
llvm-svn: 239433
Small (really small!) C++ exception handling examples work on 32-bit x86
now.
This change disables the use of .seh_* directives in WinException when
CFI is not in use. It also uses absolute symbol references in the tables
instead of imagerel32 relocations.
Also fixes a cache invalidation bug in MMI personality classification.
llvm-svn: 238575
Keno Fischer