Commit Graph

14 Commits

Author SHA1 Message Date
Reid Kleckner 785e7d282c Don't emit .seh_handler directives for any cleanup funclets
We were falsely claiming that we had an LSDA for the relevant EH
personality before this change, which could lead to the EH machinery
interpreting random adjacent data as an LSDA.

Fixes PR31317

This change is safe because cleanups can't contain exception handlers
today. We do these things to maintain that invariant:
- C++ destructors are naturally out-of-line
- __finally blocks are outlined in clang
- LLVM's inliner will not inline EH constructs into cleanups

llvm-svn: 289101
2016-12-08 20:38:46 +00:00
Hans Wennborg c4b1d20ba2 Win64: Don't emit unwind info for "leaf" functions (PR30337)
According to MSDN (see the PR), functions which don't touch any callee-saved
registers (including %rsp) don't need any unwind info.

This patch makes LLVM not emit unwind info for such functions, to save
binary size.

Differential Revision: https://reviews.llvm.org/D24748

llvm-svn: 282185
2016-09-22 19:50:05 +00:00
Hans Wennborg c39ef776fc Win64: Don't use REX prefix for direct tail calls
The REX prefix should be used on indirect jmps, but not direct ones.
For direct jumps, the unwinder looks at the offset to determine if
it's inside the current function.

Differential Revision: https://reviews.llvm.org/D24359

llvm-svn: 281003
2016-09-08 23:35:10 +00:00
Reid Kleckner 7850c9f5ca [WinEH] Make llvm.x86.seh.recoverfp work on x64
It adjusts from RSP-after-prologue to RBP, which is what SEH filters
need to do before they can use llvm.localrecover.

Fixes SEH filter captures, which were broken in r250088.

Issue reported by Alex Crichton.

llvm-svn: 255707
2015-12-15 23:40:58 +00:00
David Majnemer 3bb88c0210 [WinEH] Use operand bundles to describe call sites
SimplifyCFG allows tail merging with code which terminates in
unreachable which, in turn, makes it possible for an invoke to end up in
a funclet which it was not originally part of.

Using operand bundles on invokes allows us to determine whether or not
an invoke was part of a funclet in the source program.

Furthermore, it allows us to unambiguously answer questions about the
legality of inlining into call sites which the personality may have
trouble with.

Differential Revision: http://reviews.llvm.org/D15517

llvm-svn: 255674
2015-12-15 21:27:27 +00:00
David Majnemer 8a1c45d6e8 [IR] Reformulate LLVM's EH funclet IR
While we have successfully implemented a funclet-oriented EH scheme on
top of LLVM IR, our scheme has some notable deficiencies:
- catchendpad and cleanupendpad are necessary in the current design
  but they are difficult to explain to others, even to seasoned LLVM
  experts.
- catchendpad and cleanupendpad are optimization barriers.  They cannot
  be split and force all potentially throwing call-sites to be invokes.
  This has a noticable effect on the quality of our code generation.
- catchpad, while similar in some aspects to invoke, is fairly awkward.
  It is unsplittable, starts a funclet, and has control flow to other
  funclets.
- The nesting relationship between funclets is currently a property of
  control flow edges.  Because of this, we are forced to carefully
  analyze the flow graph to see if there might potentially exist illegal
  nesting among funclets.  While we have logic to clone funclets when
  they are illegally nested, it would be nicer if we had a
  representation which forbade them upfront.

Let's clean this up a bit by doing the following:
- Instead, make catchpad more like cleanuppad and landingpad: no control
  flow, just a bunch of simple operands;  catchpad would be splittable.
- Introduce catchswitch, a control flow instruction designed to model
  the constraints of funclet oriented EH.
- Make funclet scoping explicit by having funclet instructions consume
  the token produced by the funclet which contains them.
- Remove catchendpad and cleanupendpad.  Their presence can be inferred
  implicitly using coloring information.

N.B.  The state numbering code for the CLR has been updated but the
veracity of it's output cannot be spoken for.  An expert should take a
look to make sure the results are reasonable.

Reviewers: rnk, JosephTremoulet, andrew.w.kaylor

Differential Revision: http://reviews.llvm.org/D15139

llvm-svn: 255422
2015-12-12 05:38:55 +00:00
Joseph Tremoulet 9f467353a5 [WinEH] Only generate UnwindHelp slot for MSVCXX
Summary: Other personalities don't use this special frame slot.

Reviewers: majnemer, andrew.w.kaylor, rnk

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D14580

llvm-svn: 252778
2015-11-11 19:21:09 +00:00
David Majnemer 2652b75700 [WinEH] Don't emit CATCHRET from visitCatchPad
Instead, emit a CATCHPAD node which will get selected to a target
specific sequence.

llvm-svn: 252528
2015-11-09 23:07:48 +00:00
Reid Kleckner eb7cd6c889 [SEH] Update SEH codegen tests to use the new IR
Also Fix a buglet where SEH tables had ranges that spanned funclets.

The remaining tests using the old landingpad IR are preparation tests,
and will be deleted along with the old preparation.

llvm-svn: 249917
2015-10-09 23:05:54 +00:00
Reid Kleckner d880dc7509 [SEH] Remember to emit the last invoke range for SEH
This wasn't very observable in execution tests, because usually there is
an invoke in the catchpad that unwinds the the catchendpad but never
actually throws.

llvm-svn: 249898
2015-10-09 20:39:39 +00:00
David Majnemer 6af5f82c20 [WinEH] Refer to filter funclets using their symbol-table symbol
The relocation for the filter funclet will be against a symbol table
entry for a function instead of the section, making it easier to
understand what is going on.

llvm-svn: 249621
2015-10-07 21:34:00 +00:00
David Majnemer 7735a6d07a [WinEH] Create a separate MBB for funclet prologues
Our current emission strategy is to emit the funclet prologue in the
CatchPad's normal destination.  This is problematic because
intra-funclet control flow to the normal destination is not erroneous
and results in us reevaluating the prologue if said control flow is
taken.

Instead, use the CatchPad's location for the funclet prologue.  This
correctly models our desire to have unwind edges evaluate the prologue
but edges to the normal destination result in typical control flow.

Differential Revision: http://reviews.llvm.org/D13424

llvm-svn: 249483
2015-10-06 23:31:59 +00:00
Richard Trieu e0129e474d Call the correct overload.
Call the correct overload so a string literal does not get converted to a bool.
Also fix the test case to match the names given.

llvm-svn: 249183
2015-10-02 20:52:14 +00:00
Reid Kleckner fc64fae6e3 [WinEH] Emit __C_specific_handler tables for the new IR
We emit denormalized tables, where every range of invokes in the same
state gets a complete list of EH action entries. This is significantly
simpler than trying to infer the correct nested scoping structure from
the MI. Fortunately, for SEH, the nesting structure is really just a
size optimization.

With this, some basic __try / __except examples work.

llvm-svn: 249078
2015-10-01 21:38:24 +00:00