------------------------------------------------------------------------
r247435 | david.majnemer | 2015-09-11 13:34:34 -0400 (Fri, 11 Sep 2015) | 8 lines

[X86] Make sure startproc/endproc are paired

We used different conditions to determine if we should emit startproc vs
endproc.  Use the same condition to ensure that they will always be
paired.

This fixes PR24374.

------------------------------------------------------------------------

llvm-svn: 253742

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

Our usage of 1 was a holdover from __C_specific_handler.

llvm-svn: 239482

llvm-svn: 239449

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

llvm-svn: 239445

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

llvm-svn: 238634

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

This is in preparation for reusing this for 32-bit x86 EH table
emission.  Also updates the type name for consistency. NFC

llvm-svn: 238521

The naming was a mish-mash of old and new style. Update to be consistent
with the new. NFC.

llvm-svn: 237594

Differential Revision: http://reviews.llvm.org/D9512

llvm-svn: 237014

AsmPrinter owns the OutStreamer, so an owning pointer makes sense here. Using a
reference for this is crufty.

llvm-svn: 235752

This reverts commit r235617.

r235649 should have addressed the problems.

llvm-svn: 235667

We still have some "uses remain after removal" issues in -O0 builds.

This reverts commit r235557.

llvm-svn: 235617

This removes the -sehprepare flag and makes __C_specific_handler
functions always to use WinEHPrepare.

This was tested by building all of chromium_builder_tests and running a
few tests that use SEH, but if something breaks, we can revert this.

llvm-svn: 235557

Keep the old SEH fan-in lowering on by default for now, since projects
rely on it.  This will make it easy to test this change with a simple
flag flip.

llvm-svn: 235399

CatchHigh may be smaller than TryHigh if we reuse an outlined catch
handler for two different invokes with different EH states.  We have no
evidence which shows that CatchHigh must be greater than TryHigh or
TryLow.  We can revisit this if we turn out to be wrong.

llvm-svn: 235223

Catch blocks which are empty may be in the same state as their try
blocks.  It is not meaningful to give the catch block its own state
number in this case because it can't do anything exceptional.

llvm-svn: 235212

llvm-svn: 235170

llvm-svn: 235155

This now emits simple, unoptimized xdata tables for __C_specific_handler
based on the handlers listed in @llvm.eh.actions calls produced by
WinEHPrepare.

This adds support for running __finally blocks when exceptions are
thrown, and removes the old landingpad fan-in codepath.

I ran some manual execution tests on small basic test cases with and
without optimization, as well as on Chrome base_unittests, which uses a
small amount of SEH.  I'm sure there are bugs, and we may need to
revert.

llvm-svn: 235154

This avoids emitting code for unreachable landingpad blocks that contain
calls to llvm.eh.actions and indirectbr.

It's also a first step towards unifying the SEH and WinEH lowering
codepaths. I'm keeping the old fan-in lowering of SEH around until the
preparation version works well enough that we can switch over without
breaking existing users.

llvm-svn: 235037

Fixed the test by removing extraneous quotes.

llvm-svn: 235028

This reverts commit r235025. The test isn't passing yet.

llvm-svn: 235027

Fixes assertions in MC when a local label wasn't defined.

llvm-svn: 235025

Since adding invokes of llvm.donothing to cleanups, we come here now,
and trivial EH cleanup usage from clang fails to compile.

llvm-svn: 234948

The IPToState table must be emitted after we have generated labels for
all functions in the table.  Don't rely on the order of the list of
globals.  Instead, utilize WinEHFuncInfo to tell us how many catch
handlers we expect to outline.  Once we know we've visited all the catch
handlers, emit the cppxdata.

llvm-svn: 234566

The lack of a catch object is indicated by a frame escape index of -1.

Fixes PR23137.

llvm-svn: 234346

Now all fields in the WinEH xdata have been filled out.

llvm-svn: 234067

This add support for catching an exception such that an exception object
available to the catch handler will be initialized by the runtime.

llvm-svn: 234062

This lets us catch exceptions in simple cases.

N.B. Things that do not work include (but are not limited to):
- Throwing from within a catch handler.
- Catching an object with a named catch parameter.
- 'CatchHigh' is fictitious, we aren't sure of its purpose.
- We aren't entirely efficient with regards to the number of EH states
  that we generate.
- IP-to-State tables are sensitive to the order of emission.

llvm-svn: 233767

Generate tables in the .xdata section representing what actions to take
when an exception is thrown.  This currently fills in state for
cleanups, catch handlers are still unfinished.

llvm-svn: 233636

llvm-svn: 232475