Commit Graph

493 Commits

Author SHA1 Message Date
Thomas Lively
6bf2b40051 [WebAssembly] Expand SIMD shifts while V8's implementation disagrees
Summary:
V8 currently implements SIMD shifts as taking an immediate operation,
which disagrees with the spec proposal and the toolchain
implementation. As a stopgap measure to get things working, unroll all
vector shifts. Since this is a temporary measure, there are no tests.

Reviewers: aheejin, dschuff

Subscribers: sbc100, jgravelle-google, sunfish, dmgreen, llvm-commits

Differential Revision: https://reviews.llvm.org/D56520

llvm-svn: 351151
2019-01-15 02:16:03 +00:00
Thomas Lively
2a47e03ee4 [WebAssembly][FastISel] Do not assume naive CmpInst lowering
Summary:
Fixes https://bugs.llvm.org/show_bug.cgi?id=40172. See
test/CodeGen/WebAssembly/PR40172.ll for an explanation.

Reviewers: dschuff, aheejin

Subscribers: nikic, llvm-commits, sunfish, jgravelle-google, sbc100

Differential Revision: https://reviews.llvm.org/D56457

llvm-svn: 351127
2019-01-14 22:03:43 +00:00
Dan Gohman
8da641455c [WebAssembly] Remove tests for old intrinsics.
This is a followup to r351084 which removes the tests for the old
intrinsic names.

llvm-svn: 351086
2019-01-14 18:25:29 +00:00
Heejin Ahn
e73c7a1ab2 [WebAssembly] Fix stack pointer store check in RegStackify
Summary:
We now use __stack_pointer global and global.get/global.set instruction.
This fixes the checking routine for stack_pointer writes accordingly.

This also fixes the existing __stack_pointer test in reg-stackify.ll:
That test used to pass not because of __stack_pointer clashes but
because the function `stackpointer_callee` was not marked as `readnone`,
so it was assumed to possibly write to memory arbitraily, and
`global.set` instruction was marked as `mayStore` in the .td definition,
so they were identified as intervening writes. After we added `readnone`
to its attribute, this test fails without this patch.

Reviewers: dschuff, sunfish

Subscribers: jgravelle-google, sbc100, llvm-commits

Differential Revision: https://reviews.llvm.org/D56094

llvm-svn: 350906
2019-01-10 23:12:07 +00:00
Thomas Lively
64a39a1c4e [WebAssembly] Add unimplemented-simd128 subtarget feature
Summary:
This is a third attempt, but this time we have vetted it on Windows
first. The previous errors were due to an uninitialized class member.

Reviewers: aheejin

Subscribers: dschuff, sbc100, jgravelle-google, sunfish, jfb, llvm-commits

Differential Revision: https://reviews.llvm.org/D56560

llvm-svn: 350901
2019-01-10 22:32:11 +00:00
Thomas Lively
fdd4999b86 Revert "[WebAssembly] Add simd128-unimplemented subtarget feature"
This reverts rL350791.

llvm-svn: 350795
2019-01-10 04:09:25 +00:00
Thomas Lively
eb6f9abd41 [WebAssembly] Add simd128-unimplemented subtarget feature
This is a second attempt at r350778, which was reverted in
r350789. The only change is that the unimplemented-simd128 feature has
been renamed simd128-unimplemented, since naming it
unimplemented-simd128 somehow made the simd128 feature flag enable the
unimplemented-simd128 feature on Windows.

llvm-svn: 350791
2019-01-10 02:55:52 +00:00
Thomas Lively
fdca5fab60 Revert "[WebAssembly] Add unimplemented-simd128 subtarget feature"
This reverts L350778.

llvm-svn: 350789
2019-01-10 01:37:44 +00:00
Thomas Lively
2eeade1814 [WebAssembly] Add unimplemented-simd128 subtarget feature
Summary:
This replaces the old ad-hoc -wasm-enable-unimplemented-simd
flag. Also makes the new unimplemented-simd128 feature imply the
simd128 feature.

Reviewers: aheejin, dschuff

Subscribers: sbc100, jgravelle-google, sunfish, llvm-commits, alexcrichton

Differential Revision: https://reviews.llvm.org/D56501

llvm-svn: 350778
2019-01-09 23:59:37 +00:00
Thomas Lively
edb54b22d3 [WebAssembly] Standardize order of SIMD bitselect arguments
Summary:
For some reason the backend assumed that the condition mask would be
the first argument to the LLVM intrinsic, but everywhere else the
condition mask is the third argument.

Reviewers: aheejin

Subscribers: dschuff, sbc100, jgravelle-google, sunfish, llvm-commits

Differential Revision: https://reviews.llvm.org/D56412

llvm-svn: 350746
2019-01-09 18:13:11 +00:00
Nico Weber
b61910bbe8 Fix typo in comment
llvm-svn: 350725
2019-01-09 14:20:20 +00:00
Thomas Lively
6a87ddac9a [WebAssembly] Massive instruction renaming
Summary:
An automated renaming of all the instructions listed at
https://github.com/WebAssembly/spec/issues/884#issuecomment-426433329
as well as some similarly-named identifiers.

Reviewers: aheejin, dschuff, aardappel

Subscribers: sbc100, jgravelle-google, eraman, sunfish, jfb, llvm-commits

Differential Revision: https://reviews.llvm.org/D56338

llvm-svn: 350609
2019-01-08 06:25:55 +00:00
Heejin Ahn
777d01c756 [WebAssembly] Optimize Irreducible Control Flow
Summary:
Irreducible control flow is not that rare, e.g. it happens in malloc and
3 other places in the libc portions linked in to a hello world program.
This patch improves how we handle that code: it emits a br_table to
dispatch to only the minimal necessary number of blocks. This reduces
the size of malloc by 33%, and makes it comparable in size to asm2wasm's
malloc output.

Added some tests, and verified this passes the emscripten-wasm tests run
on the waterfall (binaryen2, wasmobj2, other).

Reviewers: aheejin, sunfish

Subscribers: mgrang, jgravelle-google, sbc100, dschuff, llvm-commits

Differential Revision: https://reviews.llvm.org/D55467

Patch by Alon Zakai (kripken)

llvm-svn: 350367
2019-01-03 23:10:11 +00:00
Thomas Lively
88590e99f2 [WebAssembly][NFC] Elaborate on simd-noopt test comment
llvm-svn: 350260
2019-01-02 20:43:08 +00:00
Thomas Lively
b6dac89c87 [WebAssembly] Fix invalid machine instrs in -O0, verify in tests
Reviewers: aheejin, dschuff

Subscribers: sbc100, jgravelle-google, sunfish, llvm-commits

Differential Revision: https://reviews.llvm.org/D55956

llvm-svn: 349889
2018-12-21 06:58:15 +00:00
Thomas Lively
feb18fe927 [WebAssembly] Emit a splat for v128 IMPLICIT_DEF
Summary:
This is a code size savings and is also important to get runnable code
while engines do not support v128.const.

Reviewers: aheejin, dschuff

Subscribers: sbc100, jgravelle-google, sunfish, llvm-commits

Differential Revision: https://reviews.llvm.org/D55910

llvm-svn: 349724
2018-12-20 04:20:32 +00:00
Thomas Lively
8dbf29af95 [WebAssembly] Gate unimplemented SIMD ops on flag
Summary:
Gates v128.const, f32x4.sqrt, f32x4.div, i8x16.extract_lane_u, and
i16x8.extract_lane_u on the --wasm-enable-unimplemented-simd flag,
since these ops are not implemented yet in V8.

Reviewers: aheejin, dschuff

Subscribers: sbc100, jgravelle-google, sunfish, llvm-commits

Differential Revision: https://reviews.llvm.org/D55904

llvm-svn: 349720
2018-12-20 02:10:22 +00:00
Wouter van Oortmerssen
d3c544aa6e [WebAssembly] Fix assembler parsing of br_table.
Summary:
We use `variable_ops` in the tablegen defs to denote the list of
branch targets in `br_table`, but unlike other uses of `variable_ops`
(e.g. call) the these branch targets need to actually be encoded in the
instruction. The existing tables for `variable_ops` cause not operands
to be accepted by the assembly matcher.

Following the example of ARM:
2cc0a7da87/lib/Target/ARM/ARMInstrInfo.td (L550-L555)
we introduce a new operand type to capture this list, and we use the
same {} syntax as ARM as well to differentiate them from regular
integer operands.

Also removed definition and use of TSFlags in tablegen defs, since
`br_table` now has a non-variable_ops immediate operand, so the
previous logic of only the variable_ops arguments being labels didn't
make sense anymore.

Reviewers: dschuff, aheejin, sunfish

Subscribers: javed.absar, sbc100, jgravelle-google, kristof.beyls, llvm-commits

Differential Revision: https://reviews.llvm.org/D55401

llvm-svn: 349405
2018-12-17 22:04:44 +00:00
Heejin Ahn
be5e5874f6 [WebAssembly] Add '.eventtype' directive support
Summary:
This patch supports `.eventtype` directive printing and parsing in the
same syntax with `.functype`.

Reviewers: aardappel, sbc100

Subscribers: dschuff, sbc100, jgravelle-google, sunfish, llvm-commits

Differential Revision: https://reviews.llvm.org/D55353

llvm-svn: 348818
2018-12-11 01:11:04 +00:00
Sam Clegg
4791a668f5 [WebAssembly] WebAssemblyLowerEmscriptenEHSjLj: use getter/setter for accessing tempRet0
Rather than assuming that `tempRet0` exists in linear memory only assume
the getter/setter functions exist.  This avoids conflicting with
binaryen which declares a wasm global for this purpose and defines it's
own getter and setter for that.

The other advantage of doing things this way is that it leaving
it up to the linker/finalizer to decide how to actually store this
temporary.  As it happens binaryen uses a wasm global which is more
appropriate since it is thread safe.

This also allows us to change the way this is stored in the future
(memory, TLS memory, wasm global) without modifying LLVM.

This is part of a 4 part change:
LLVM: https://reviews.llvm.org/D53240
fastcomp: https://github.com/kripken/emscripten-fastcomp/pull/237
emscripten: https://github.com/kripken/emscripten/pull/7358
binaryen: https://github.com/WebAssembly/binaryen/pull/1709

Differential Revision: https://reviews.llvm.org/D53240

llvm-svn: 347340
2018-11-20 19:25:07 +00:00
Wouter van Oortmerssen
49482f824a [WebAssembly] replaced .param/.result by .functype
Summary:
This makes it easier/cleaner to generate a single signature from
this directive. Also:
- Adds the symbol name, such that we don't depend on the location
  of this directive anymore.
- Actually constructs the signature in the assembler, and make the
  assembler own it.
- Refactor the use of MVT vs ValType in the streamer and assembler
  to require less conversions overall.
- Changed 700 or so tests to use it.

Reviewers: sbc100, dschuff

Subscribers: jgravelle-google, eraman, aheejin, sunfish, jfb, llvm-commits

Differential Revision: https://reviews.llvm.org/D54652

llvm-svn: 347228
2018-11-19 17:10:36 +00:00
Heejin Ahn
e0f8b9bfc6 [WebAssembly] Add null streamer support
Summary: Now `llc -filetype=null` works.

Reviewers: eush

Subscribers: dschuff, jgravelle-google, sbc100, sunfish, llvm-commits

Differential Revision: https://reviews.llvm.org/D54660

llvm-svn: 347155
2018-11-18 11:58:47 +00:00
Sam Clegg
a2827edc2f [WebAssembly] Cleanup unused declares in test code. NFC.
In one case probably you have be using it, in the other it
looks like it was redundant.

Differential Revision: https://reviews.llvm.org/D54644

llvm-svn: 347098
2018-11-16 21:20:00 +00:00
Sam Clegg
74f5fd4e32 [WebAssembly] Default to static reloc model
Differential Revision: https://reviews.llvm.org/D54637

llvm-svn: 347073
2018-11-16 18:59:51 +00:00
Heejin Ahn
095796a391 [WebAssembly] Split BBs after throw instructions
Summary:
`throw` instruction is a terminator in wasm, but BBs were not splitted
after `throw` instructions, causing machine instruction verifier to
fail.

This patch
- Splits BBs after `throw` instructions in WasmEHPrepare and adding an
  unreachable instruction after `throw`, which will be deleted in
  LateEHPrepare pass
- Refactors WasmEHPrepare into two member functions
- Changes the semantics of `eraseBBsAndChildren` in LateEHPrepare pass
  to match that of WasmEHPrepare pass, which is newly added. Now
  `eraseBBsAndChildren` does not delete BBs with remaining predecessors.
- Fixes style nits, making static function names conform to clang-tidy
- Re-enables the test temporarily disabled by rL346840 && rL346845

Reviewers: dschuff

Subscribers: sbc100, jgravelle-google, sunfish, llvm-commits

Differential Revision: https://reviews.llvm.org/D54571

llvm-svn: 347003
2018-11-16 00:47:18 +00:00
Heejin Ahn
da419bdb5e [WebAssembly] Add support for the event section
Summary:
This adds support for the 'event section' specified in the exception
handling proposal. (This was named 'exception section' first, but later
renamed to 'event section' to take possibilities of other kinds of
events into consideration. But currently we only store exception info in
this section.)

The event section is added between the global section and the export
section. This is for ease of validation per request of the V8 team.

This patch:
- Creates the event symbol type, which is a weak symbol
- Makes 'throw' instruction take the event symbol '__cpp_exception'
- Adds relocation support for events
- Adds WasmObjectWriter / WasmObjectFile (Reader) support
- Adds obj2yaml / yaml2obj support
- Adds '.eventtype' printing support

Reviewers: dschuff, sbc100, aardappel

Subscribers: jgravelle-google, sunfish, llvm-commits

Differential Revision: https://reviews.llvm.org/D54096

llvm-svn: 346825
2018-11-14 02:46:21 +00:00
Sam Clegg
f98ba05f3d [WebAssembly] Fix broken assumption that all bitcasts are to functions types
Specifically, we can bitcast to void.

Fixes PR39591

Differential Revision: https://reviews.llvm.org/D54447

llvm-svn: 346778
2018-11-13 19:14:02 +00:00
Simon Atanasyan
9d87256d3d [WebAssembly] Mark immediates.ll as XFAILed on MIPS hosts
Usually MIPS hosts uses a legacy (non IEEE 754-2008) encoding for NaNs.
Tests like `nan_f32` failed in attempt to compare hard-coded IEEE
754-2008 NaN value and a legacy NaN value provided by a system.

llvm-svn: 346773
2018-11-13 18:14:29 +00:00
Wouter van Oortmerssen
cc75e77df5 [WebAssembly] Added WasmAsmParser.
Summary:
This is to replace the ELFAsmParser that WebAssembly was using, which
so far was a stub that didn't do anything, and couldn't work correctly
with wasm.

This new class is there to implement generic directives related to
wasm as a binary format. Wasm target specific directives are still
parsed in WebAssemblyAsmParser as before. The two classes now
cooperate more correctly too.

Also implemented .result which was missing. Any unknown directives
will now result in errors.

Reviewers: dschuff, sbc100

Subscribers: mgorny, jgravelle-google, eraman, aheejin, sunfish, llvm-commits

Differential Revision: https://reviews.llvm.org/D54360

llvm-svn: 346700
2018-11-12 20:15:01 +00:00
Thomas Lively
97bef83690 [WebAssembly] Disable custom NaN payload tests
Summary:
These tests fail on 32-bit builds because NaN payload bits in floating point
immediates are not necessarily preserved through compilation. This is because
the MC layer uses native doubles to store these values. The tests will be
reenabled once this problem has been fixed or deleted if we decide we don't care
about lowering payload bits.

Reviewers: aheejin, dschuff

Subscribers: sbc100, jgravelle-google, sunfish, llvm-commits

Differential Revision: https://reviews.llvm.org/D54353

llvm-svn: 346558
2018-11-09 22:04:37 +00:00
Thomas Lively
38c902bc2e [WebAssembly] Lower select for vectors
Summary:

Reviewers: aheejin, dschuff

Subscribers: sbc100, jgravelle-google, sunfish, llvm-commits

Differential Revision: https://reviews.llvm.org/D53675

llvm-svn: 346462
2018-11-09 01:38:44 +00:00
Heejin Ahn
0c68a875fa [WebAssembly] Fix LowerEmscriptenEHSjLj when there's only longjmp
Summary:
The pass incorrectly assumed if there's a longjmp declaration in the
module, there is also a setjmp function declaration. Fixed it, and now
the pass only converts longjmp and does not do any other transformation
when there's no setjmp declaration in the module.

Fixes PR39562.

Reviewers: jgravelle-google, sbc100

Subscribers: dschuff, sunfish, llvm-commits

Differential Revision: https://reviews.llvm.org/D54273

llvm-svn: 346445
2018-11-08 22:56:26 +00:00
Thomas Lively
897171902b [WebAssembly] Add V128 to WebAssemblyInstrInfo::copyPhysReg
Reviewers: aheejin, dschuff

Subscribers: sbc100, jgravelle-google, sunfish, llvm-commits

Differential Revision: https://reviews.llvm.org/D53872

llvm-svn: 346384
2018-11-08 02:35:28 +00:00
Sam Clegg
5292d17ec8 Revert "[WebAssembly] Fixup main signature by default"
This reverts rL345880.  It caused some test failures on the
webassembly waterfall.  e.g. binaryen2.test_mainenv fails due
the fact that `envp` ends up being undef rather than 0.

Differential Revision: https://reviews.llvm.org/D54117

llvm-svn: 346187
2018-11-06 00:31:02 +00:00
Heejin Ahn
5b023e07ea [WebAssembly] Fix bugs in rethrow depth counting and InstPrinter
Summary:
EH stack depth is incremented at `try` and decremented at `catch`. When
there are more than two catch instructions for a try instruction, we
shouldn't count non-first catches when calculating EH stack depths.

This patch fixes two bugs:
- CFGStackify: Exclude `catch_all` in the terminate catch pad when
  calculating EH pad stack, because when we have multiple catches for a
  try we should count only the first catch instruction when calculating
  EH pad stack.
- InstPrinter: The initial intention was also to exclude non-first
  catches, but it didn't account nested try-catches, so it failed on
  this case:
```
try
  try
  catch
  end
catch    <-- (1)
end
```
In the example, when we are at the catch (1), the last seen EH
instruction is not `try` but `end_try`, violating the wrong assumption.

We don't need these after we switch to the second proposal because there
is gonna be only one `catch` instruction. But anyway before then these
bugfixes are necessary for keep trunk in working state.

Reviewers: dschuff

Subscribers: sbc100, jgravelle-google, sunfish, llvm-commits

Differential Revision: https://reviews.llvm.org/D53819

llvm-svn: 346029
2018-11-02 18:38:52 +00:00
Wouter van Oortmerssen
3231e518a3 [WebAssembly] Added a .globaltype directive to .s output.
Summary:
Assembly output can use globals like __stack_pointer implicitly,
but has no way of indicating the type of such a global, which makes
it hard for tools processing it (such as the MC Assembler) to
reconstruct this information.

The improved assembler directives parsing (in progress in
https://reviews.llvm.org/D53842) will make use of this information.

Also deleted code for the .import_global directive which was unused.

New test case in userstack.ll

Reviewers: dschuff, sbc100

Subscribers: jgravelle-google, aheejin, sunfish, llvm-commits

Differential Revision: https://reviews.llvm.org/D54012

llvm-svn: 345917
2018-11-02 00:45:00 +00:00
Thomas Lively
b2382c8bf7 [WebAssembly] General vector shift lowering
Summary: Adds support for lowering non-splat shifts.

Reviewers: aheejin, dschuff

Subscribers: sbc100, jgravelle-google, sunfish, llvm-commits

Differential Revision: https://reviews.llvm.org/D53625

llvm-svn: 345916
2018-11-02 00:39:57 +00:00
Thomas Lively
fb84fd7c8e [WebAssembly] Expand inserts and extracts with variable indices
Reviewers: aheejin, dschuff

Subscribers: sbc100, jgravelle-google, sunfish, llvm-commits

Differential Revision: https://reviews.llvm.org/D53964

llvm-svn: 345913
2018-11-02 00:06:56 +00:00
Sam Clegg
ddf049869a [WebAssembly] Fixup main signature by default
Differential Revision: https://reviews.llvm.org/D53396

llvm-svn: 345880
2018-11-01 19:38:44 +00:00
Thomas Lively
d4891a1b7a [WebAssembly] Lower vselect
Reviewers: aheejin, dschuff

Subscribers: sbc100, jgravelle-google, sunfish, llvm-commits

Differential Revision: https://reviews.llvm.org/D53630

llvm-svn: 345797
2018-11-01 00:01:02 +00:00
Thomas Lively
b61232eacd [WebAssembly] Process p2align operands for SIMD loads and stores
Reviewers: aheejin, dschuff

Subscribers: sbc100, jgravelle-google, sunfish, llvm-commits

Differential Revision: https://reviews.llvm.org/D53886

llvm-svn: 345795
2018-10-31 23:58:20 +00:00
Thomas Lively
6ff31fe34d [WebAssembly] Handle vector IMPLICIT_DEFs.
Summary:
Also reduce the test case for implicit defs and test it with all
register classes.

Reviewers: aheejin, dschuff

Subscribers: sbc100, jgravelle-google, sunfish, llvm-commits

Differential Revision: https://reviews.llvm.org/D53855

llvm-svn: 345794
2018-10-31 23:50:53 +00:00
Thomas Lively
eb15d00193 [WebAssembly] Lower away condition truncations for scalar selects
Reviewers: aheejin, dschuff

Subscribers: sbc100, jgravelle-google, sunfish, llvm-commits

Differential Revision: https://reviews.llvm.org/D53676

llvm-svn: 345521
2018-10-29 18:38:12 +00:00
Heejin Ahn
24faf859e5 Reland "[WebAssembly] LSDA info generation"
Summary:
This adds support for LSDA (exception table) generation for wasm EH.
Wasm EH mostly follows the structure of Itanium-style exception tables,
with one exception: a call site table entry in wasm EH corresponds to
not a call site but a landing pad.

In wasm EH, the VM is responsible for stack unwinding. After an
exception occurs and the stack is unwound, the control flow is
transferred to wasm 'catch' instruction by the VM, after which the
personality function is called from the compiler-generated code. (Refer
to WasmEHPrepare pass for more information on this part.)

This patch:
- Changes wasm.landingpad.index intrinsic to take a token argument, to
make this 1:1 match with a catchpad instruction
- Stores landingpad index info and catch type info MachineFunction in
before instruction selection
- Lowers wasm.lsda intrinsic to an MCSymbol pointing to the start of an
exception table
- Adds WasmException class with overridden methods for table generation
- Adds support for LSDA section in Wasm object writer

Reviewers: dschuff, sbc100, rnk

Subscribers: mgorny, jgravelle-google, sunfish, llvm-commits

Differential Revision: https://reviews.llvm.org/D52748

llvm-svn: 345345
2018-10-25 23:55:10 +00:00
Heejin Ahn
3103d3dcd1 [WebAssembly] Support EH instructions in InstPrinter
Summary: This adds support for exception handling instructions to InstPrinter.

Reviewers: dschuff, aardappel

Subscribers: sbc100, jgravelle-google, sunfish, llvm-commits

Differential Revision: https://reviews.llvm.org/D53634

llvm-svn: 345343
2018-10-25 23:45:48 +00:00
Heejin Ahn
1d13e6be37 Address comments
- Add llvm-mc test case (and delete the old one)
- Change report_fatal_error to assertions

llvm-svn: 345334
2018-10-25 23:35:14 +00:00
Heejin Ahn
1147d91402 [WebAssembly] Error out when block/loop markers mismatch
Summary:
Currently InstPrinter ignores if there are mismatches between block/loop
and end markers by skipping the case if ControlFlowStack is empty. I
guess it is better to explicitly error out in this case, because this
signals invalid input.

Reviewers: aardappel

Subscribers: dschuff, sbc100, jgravelle-google, sunfish, llvm-commits

Differential Revision: https://reviews.llvm.org/D53620

llvm-svn: 345333
2018-10-25 23:35:13 +00:00
Thomas Lively
0aad98fd07 [WebAssembly] Use target-independent saturating add
Reviewers: aheejin, dschuff

Subscribers: sbc100, jgravelle-google, sunfish, llvm-commits

Differential Revision: https://reviews.llvm.org/D53721

llvm-svn: 345299
2018-10-25 19:06:13 +00:00
Thomas Lively
325c9c5e84 [WebAssembly] Set LoadExt and TruncStore actions for SIMD types
Summary: Fixes part of the problem reported in bug 39275.

Reviewers: aheejin, dschuff

Subscribers: sbc100, jgravelle-google, sunfish, llvm-commits, alexcrichton

Differential Revision: https://reviews.llvm.org/D53542

llvm-svn: 345230
2018-10-25 01:46:07 +00:00
Heejin Ahn
ac764aa88e [WebAssembly] Fix immediate of rethrow when throwing to caller
Summary:
Currently when assigning depths 'rethrow' does not take the whole
control flow stack into accounts but only considers EH pad stacks. When
assigning depth immmediates to rethrows, in normal cases it is done
correctly but when a rethrow instruction throws up to a caller, i.e., we
convert a pseudo RETHROW_TO_CALLER instruction to a rethrow, it
mistakenly compute the whole stack depth.

Reviewers: dschuff

Subscribers: sbc100, jgravelle-google, sunfish, llvm-commits

Differential Revision: https://reviews.llvm.org/D53619

llvm-svn: 345223
2018-10-24 23:31:24 +00:00