Commit Graph

40 Commits

Author SHA1 Message Date
Sam Clegg 492f752969 [WebAssembly] Initial implementation of PIC code generation
This change implements lowering of references global symbols in PIC
mode.

This change implements lowering of global references in PIC mode using a
new @GOT reference type. @GOT references can be used with function or
data symbol names combined with the get_global instruction. In this case
the linker will insert the wasm global that stores the address of the
symbol (either in memory for data symbols or in the wasm table for
function symbols).

For now I'm continuing to use the R_WASM_GLOBAL_INDEX_LEB relocation
type for this type of reference which means that this relocation type
can refer to either a global or a function or data symbol. We could
choose to introduce specific relocation types for GOT entries in the
future.  See the current dynamic linking proposal:

https://github.com/WebAssembly/tool-conventions/blob/master/DynamicLinking.md

Differential Revision: https://reviews.llvm.org/D54647

llvm-svn: 357022
2019-03-26 19:46:15 +00:00
Sam Clegg 8fffa1dfa3 [WebAssembly] Remove unneeded MCSymbolRefExpr variants
We record the type of the symbol (event/function/data/global) in the
MCWasmSymbol and so it should always be clear how to handle a relocation
based on the symbol itself.

The exception is a function which still needs the special @TYPEINDEX
then the relocation contains the signature rather than the address
of the functions.

Differential Revision: https://reviews.llvm.org/D58472

llvm-svn: 354697
2019-02-22 22:29:34 +00:00
Heejin Ahn 18c56a0762 [WebAssembly] clang-tidy (NFC)
Summary:
This patch fixes clang-tidy warnings on wasm-only files.
The list of checks used is:
`-*,clang-diagnostic-*,llvm-*,misc-*,-misc-unused-parameters,readability-identifier-naming,modernize-*`
(LLVM's default .clang-tidy list is the same except it does not have
`modernize-*`. But I've seen in multiple CLs in LLVM the modernize style
was recommended and code was fixed based on the style, so I added it as
well.)

The common fixes are:
- Variable names start with an uppercase letter
- Function names start with a lowercase letter
- Use `auto` when you use casts so the type is evident
- Use inline initialization for class member variables
- Use `= default` for empty constructors / destructors
- Use `using` in place of `typedef`

Reviewers: sbc100, tlively, aardappel

Subscribers: dschuff, sunfish, jgravelle-google, yurydelendik, kripken, MatzeB, mgorny, rupprecht, llvm-commits

Differential Revision: https://reviews.llvm.org/D57500

llvm-svn: 353075
2019-02-04 19:13:39 +00:00
Heejin Ahn d6f487863d [WebAssembly] Exception handling: Switch to the new proposal
Summary:
This switches the EH implementation to the new proposal:
https://github.com/WebAssembly/exception-handling/blob/master/proposals/Exceptions.md
(The previous proposal was
 https://github.com/WebAssembly/exception-handling/blob/master/proposals/old/Exceptions.md)

- Instruction changes
  - Now we have one single `catch` instruction that returns a except_ref
    value
  - `throw` now can take variable number of operations
  - `rethrow` does not have 'depth' argument anymore
  - `br_on_exn` queries an except_ref to see if it matches the tag and
    branches to the given label if true.
  - `extract_exception` is a pseudo instruction that simulates popping
    values from wasm stack. This is to make `br_on_exn`, a very special
    instruction, work: `br_on_exn` puts values onto the stack only if it
    is taken, and the # of values can vay depending on the tag.

- Now there's only one `catch` per `try`, this patch removes all special
  handling for terminate pad with a call to `__clang_call_terminate`.
  Before it was the only case there are two catch clauses (a normal
  `catch` and `catch_all` per `try`).

- Make `rethrow` act as a terminator like `throw`. This splits BB after
  `rethrow` in WasmEHPrepare, and deletes an unnecessary `unreachable`
  after `rethrow` in LateEHPrepare.

- Now we stop at all catchpads (because we add wasm `catch` instruction
  that catches all exceptions), this creates new
  `findWasmUnwindDestinations` function in SelectionDAGBuilder.

- Now we use `br_on_exn` instrution to figure out if an except_ref
  matches the current tag or not, LateEHPrepare generates this sequence
  for catch pads:
```
  catch
  block i32
  br_on_exn $__cpp_exception
  end_block
  extract_exception
```

- Branch analysis for `br_on_exn` in WebAssemblyInstrInfo

- Other various misc. changes to switch to the new proposal.

Reviewers: dschuff

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

Differential Revision: https://reviews.llvm.org/D57134

llvm-svn: 352598
2019-01-30 03:21:57 +00:00
Chandler Carruth 2946cd7010 Update the file headers across all of the LLVM projects in the monorepo
to reflect the new license.

We understand that people may be surprised that we're moving the header
entirely to discuss the new license. We checked this carefully with the
Foundation's lawyer and we believe this is the correct approach.

Essentially, all code in the project is now made available by the LLVM
project under our new license, so you will see that the license headers
include that license only. Some of our contributors have contributed
code under our old license, and accordingly, we have retained a copy of
our old license notice in the top-level files in each project and
repository.

llvm-svn: 351636
2019-01-19 08:50:56 +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
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
Thomas Lively c63b5fcb2a [WebAssembly][NFC] Remove WebAssemblyStackifier TableGen backend
Summary:
Replace its functionality with a TableGen InstrInfo relational
instruction mapping. Although arguably more complex than the TableGen
backend, the relational mapping is a smaller maintenance burden than a
TableGen backend.

Reviewers: aardappel, aheejin, dschuff

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

Differential Revision: https://reviews.llvm.org/D53307

llvm-svn: 344962
2018-10-22 21:55:26 +00:00
Krasimir Georgiev 547d824da6 Revert "[WebAssembly] LSDA info generation"
This reverts commit r344575.
Newly introduced test eh-lsda.ll.test fails with use-after-free under
ASAN build.

llvm-svn: 344639
2018-10-16 18:50:09 +00:00
Heejin Ahn 0981eaab47 [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: 344575
2018-10-16 00:09:12 +00:00
Derek Schuff 77a7a38006 [WebAssembly] Refactor WasmSignature and use it for MCSymbolWasm
MCContext does not destroy MCSymbols on shutdown. So, rather than putting
SmallVectors (which may heap-allocate) inside MCSymbolWasm, use unowned pointer
to a WasmSignature instead. The signatures are now owned by the AsmPrinter.
Also uses WasmSignature instead of param and result vectors in TargetStreamer,
and leaves some TODOs for further simplification.

 Differential Revision: https://reviews.llvm.org/D52580

llvm-svn: 343733
2018-10-03 22:22:48 +00:00
Derek Schuff 70ce1af9fa WebAssembly: Rename GetSignature to GetLibcallSignature [NFC]
llvm-svn: 343275
2018-09-27 22:20:33 +00:00
Thomas Lively 6f21a13675 [WebAssembly] Add V128 value type to binary format
Summary: Adds the necessary support to lib/ObjectYAML and fixes SIMD
calls to allow the tests to work. Also removes some dead code that
would otherwise have to have been updated.

Reviewers: aheejin, dschuff, sbc100

Subscribers: jgravelle-google, sunfish, llvm-commits

Differential Revision: https://reviews.llvm.org/D52105

llvm-svn: 342689
2018-09-20 22:04:44 +00:00
Heejin Ahn f208f6311b [WebAssembly] clang-format (NFC)
Summary: This patch runs clang-format on all wasm-only files.

Reviewers: aardappel, dschuff, sunfish, tlively

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

Differential Revision: https://reviews.llvm.org/D51447

llvm-svn: 341439
2018-09-05 01:27:38 +00:00
Wouter van Oortmerssen 2d5fcf07a8 [WebAssembly] Fixed stale assert message in WebAssemblyMCInstLower
llvm-svn: 341423
2018-09-04 22:59:05 +00:00
Thomas Lively adb6da10b8 [WebAssembly][NFC] Document stackifier tablegen backend
Summary:
Add comments to help readers avoid having to read tablegen backends to
understand the code. Also remove unecessary breaks from the output.

Reviewers: dschuff, aheejin

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

Differential Revision: https://reviews.llvm.org/D51371

llvm-svn: 340864
2018-08-28 18:49:47 +00:00
Thomas Lively 211874d2f3 [WebAssembly] TableGen backend for stackifying instructions
Summary:
The new stackification backend generates the giant switch statement
used to translate instructions to their stackified forms. I did this
because it was more interesting than adding all the different vector
versions of the various SIMD instructions to the switch statment
manually.

Reviewers: aardappel, aheejin, dschuff

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

Differential Revision: https://reviews.llvm.org/D51318

llvm-svn: 340781
2018-08-27 22:02:09 +00:00
Wouter van Oortmerssen 8a9cb242fb [WebAssembly] Added default stack-only instruction mode for MC.
Summary:
Made it convert from register to stack based instructions, and removed the registers.
Fixes to related code that was expecting register based instructions.
Added the correct testing flag to all tests, depending on what the
format they were expecting so far.
Translated one test to stack format as example: reg-stackify-stack.ll

tested:
llvm-lit -v `find test -name WebAssembly`
unittests/MC/*

Reviewers: dschuff, sunfish

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

Differential Revision: https://reviews.llvm.org/D51241

llvm-svn: 340750
2018-08-27 15:45:51 +00:00
Nicholas Wilson e408a89a3a [WebAssembly] Cleanup of the way globals and global flags are handled
Differential Revision: https://reviews.llvm.org/D44030

llvm-svn: 338894
2018-08-03 14:33:37 +00:00
Sam Clegg cf2a9e28b1 [WebAssembly] Remove ELF file support.
This support was partial and temporary.  Now that we have
wasm object file support its no longer needed.

Differential Revision: https://reviews.llvm.org/D48744

llvm-svn: 337222
2018-07-16 23:09:29 +00:00
Adrian Prantl 5f8f34e459 Remove \brief commands from doxygen comments.
We've been running doxygen with the autobrief option for a couple of
years now. This makes the \brief markers into our comments
redundant. Since they are a visual distraction and we don't want to
encourage more \brief markers in new code either, this patch removes
them all.

Patch produced by

  for i in $(git grep -l '\\brief'); do perl -pi -e 's/\\brief //g' $i & done

Differential Revision: https://reviews.llvm.org/D46290

llvm-svn: 331272
2018-05-01 15:54:18 +00:00
Sam Clegg 503fdea3cb [WebAssembly] Fix broken gcc build after rL326454
The gcc builders were broken by rL326454
See: https://reviews.llvm.org/D43921

llvm-svn: 326460
2018-03-01 18:48:08 +00:00
Sam Clegg 03e101f1b0 [WebAssembly] Use uint8_t for single byte values to match the spec
The original BinaryEncoding.md document used to specify that
these values were `varint7`, but the official spec lists them
explicitly as single byte values and not LEB.

A similar change for wabt is in flight:
 https://github.com/WebAssembly/wabt/pull/782

Differential Revision: https://reviews.llvm.org/D43921

llvm-svn: 326454
2018-03-01 18:06:21 +00:00
Sam Clegg 6c899ba6de [WebAssembly] Add first claass symbol table to wasm objects
This is combination of two patches by Nicholas Wilson:
  1. https://reviews.llvm.org/D41954
  2. https://reviews.llvm.org/D42495

Along with a few local modifications:
- One change I made was to add the UNDEFINED bit to the binary format
  to avoid the extra byte used when writing data symbols.  Although this
  bit is redundant for other symbols types (i.e. undefined can be
  implied if a function or global is a wasm import)
- I prefer to be explicit and consistent and not have derived flags.
- Some field renaming.
- Some reverting of unrelated minor changes.
- No test output differences.

Differential Revision: https://reviews.llvm.org/D43147

llvm-svn: 325860
2018-02-23 05:08:34 +00:00
David Blaikie 2110924909 Fix WebAssembly backend for some LLVM API changes
llvm-svn: 320893
2017-12-15 23:52:06 +00:00
Sam Clegg 9bf73c078b [WebAssembly] Fix types for address taken functions
Differential Revision: https://reviews.llvm.org/D34966

llvm-svn: 307198
2017-07-05 20:25:08 +00:00
Derek Schuff e2688c432f [WebAssembly] Use LEB encoding for value types
Previously we were using the encoded LEB hex values
for the value types.  This change uses the decoded
negative value and the LEB encoder to write them out.

Differential Revision: https://reviews.llvm.org/D30847

Patch by Sam Clegg

llvm-svn: 297777
2017-03-14 20:23:22 +00:00
Dan Gohman d934cb8806 [WebAssembly] Basic support for Wasm object file encoding.
With the "wasm32-unknown-unknown-wasm" triple, this allows writing out
simple wasm object files, and is another step in a larger series toward
migrating from ELF to general wasm object support. Note that this code
and the binary format itself is still experimental.

llvm-svn: 296190
2017-02-24 23:18:00 +00:00
Richard Trieu 3de487b2e8 [WebAssembly] Use print instead of dump method.
This fixes non-debug non-assert builds after r293359.

llvm-svn: 293368
2017-01-28 03:23:49 +00:00
Dan Gohman 1d68e80f26 [WebAssembly] Make CFG stackification independent of basic-block labels.
This patch changes the way labels are referenced. Instead of referencing the
basic-block label name (eg. .LBB0_0), instructions now just have an immediate
which indicates the depth in the control-flow stack to find a label to jump to.
This makes them much closer to what we expect to have in the binary encoding,
and avoids the problem of basic-block label names not being explicit in the
binary encoding.

Also, it terminates blocks and loops with end_block and end_loop instructions,
rather than basic-block label names, for similar reasons.

This will also fix problems where two constructs appear to have the same label,
because we no longer explicitly use labels, so consumers that need labels will
presumably create their own labels, and presumably they won't reuse labels
when they do.

This patch does make the code a little more awkward to read; as a partial
mitigation, this patch also introduces comments showing where the labels are,
and comments on each branch showing where it's branching to.

llvm-svn: 257505
2016-01-12 19:14:46 +00:00
Dan Gohman 26c6765bd6 [WebAssembly] Define WebAssembly-specific relocation codes.
Currently WebAssembly has two kinds of relocations; data addresses and
function addresses. This adds ELF relocations for them, as well as an
MC symbol kind to indicate which type of relocation is needed.

llvm-svn: 257416
2016-01-11 23:38:05 +00:00
Dan Gohman a2b2cdc813 [WebAssembly] Trim unneeded #includes. NFC.
llvm-svn: 256301
2015-12-22 23:45:21 +00:00
Dan Gohman a4b710a74f [WebAssembly] Enable folding of offsets into global variable addresses.
llvm-svn: 254882
2015-12-06 19:33:32 +00:00
Dan Gohman 9551a44d0c [WebAssembly] Delete an obsolete TODO comment.
llvm-svn: 254272
2015-11-29 23:09:41 +00:00
Dan Gohman 7a6b9825ce [WebAssembly] Minor clang-format and selected clang-tidy cleanups. NFC.
llvm-svn: 254267
2015-11-29 22:32:02 +00:00
Dan Gohman 2c8fe6a428 [WebAssembly] Codegen support for ISD::ExternalSymbol
llvm-svn: 254075
2015-11-25 16:44:29 +00:00
Dan Gohman cf4748f180 [WebAssembly] Reapply r252858, with svn add for the new file.
Switch to MC for instruction printing.

This encompasses several changes which are all interconnected:
 - Use the MC framework for printing almost all instructions.
 - AsmStrings are now live.
 - This introduces an indirection between LLVM vregs and WebAssembly registers,
   and a new pass, WebAssemblyRegNumbering, for computing a basic the mapping.
   This addresses some basic issues with argument registers and unused registers.
 - The way ARGUMENT instructions are handled no longer generates redundant
   get_local+set_local for every argument.

This also changes the assembly syntax somewhat; most notably, MC's printing
does not use sigils on label names, so those are no longer present, and
push/pop now have a sigil to keep them unambiguous.

The usage of set_local/get_local/$push/$pop will continue to evolve
significantly. This patch is just one step of a larger change.

llvm-svn: 252910
2015-11-12 17:04:33 +00:00
Hans Wennborg 7384a2de02 Revert r252858: "[WebAssembly] Switch to MC for instruction printing."
It broke the CMake build:

"Cannot find source file: WebAssemblyRegNumbering.cpp"

llvm-svn: 252897
2015-11-12 14:37:56 +00:00
Dan Gohman 9dd55a8065 [WebAssembly] Switch to MC for instruction printing.
This encompasses several changes which are all interconnected:
 - Use the MC framework for printing almost all instructions.
 - AsmStrings are now live.
 - This introduces an indirection between LLVM vregs and WebAssembly registers,
   and a new pass, WebAssemblyRegNumbering, for computing a basic the mapping.
   This addresses some basic issues with argument registers and unused registers.
 - The way ARGUMENT instructions are handled no longer generates redundant
   get_local+set_local for every argument.

This also changes the assembly syntax somewhat; most notably, MC's printing
use sigils on label names, so those are no longer present, and push/pop now
have a sigil to keep them unambiguous.

The usage of set_local/get_local/$push/$pop will continue to evolve
significantly. This patch is just one step of a larger change.

llvm-svn: 252858
2015-11-12 06:10:03 +00:00
Dan Gohman e9361d58ff [WebAssembly] Add WebAssemblyMCInstLower.cpp.
This isn't used yet; it's just a start towards eventually using MC to
do instruction printing, and eventually binary encoding.

llvm-svn: 252194
2015-11-05 19:28:16 +00:00