llvm-svn: 297489

llvm-svn: 295259

Also clean up description.

llvm-svn: 294624

llvm-svn: 294516

llvm-svn: 294436

llvm-svn: 288500

llvm-svn: 288268

llvm-svn: 286710

llvm-svn: 286269

This contains just enough for lib/Target/RISCV to compile. Notably a basic 
RISCVTargetMachine and RISCVTargetInfo. At this point you can attempt llc 
-march=riscv32 myinput.ll and will find it fails due to the lack of 
MCAsmInfo.

See http://lists.llvm.org/pipermail/llvm-dev/2016-August/103748.html for 
further discussion

Differential Revision: https://reviews.llvm.org/D23560

llvm-svn: 285712

llvm-svn: 281628

llvm-svn: 280667

llvm-svn: 277503

As agreed with Daniel Sanders, I'm taking over as code owner
for the MIPS backend.

llvm-svn: 276529

llvm-svn: 276321

llvm-svn: 274574

llvm-svn: 270936

llvm-svn: 270915

Owen no longer has time to tend to the yaks in SelectionDAG.

llvm-svn: 270253

llvm-svn: 269073

llvm-svn: 265182

Add the Lanai backend to lib/Target.

General Lanai backend discussion on llvm-dev thread "[RFC] Lanai backend" (http://lists.llvm.org/pipermail/llvm-dev/2016-February/095118.html).

Differential Revision: http://reviews.llvm.org/D17011

llvm-svn: 264578

Apparently this makes my email address easier to find.

llvm-svn: 262951

llvm-svn: 259280

llvm-svn: 256106

llvm-svn: 254620

Summary:
As I maintain the AVR backend and am currently in the process of migrating it in tree, it makes sense to add myself as the code owner.

Thoughts welcome!

Differential Revision: http://reviews.llvm.org/D14002

llvm-svn: 251471

llvm-svn: 251367

llvm-svn: 246954

llvm-svn: 244823

This WebAssembly backend is just a skeleton at this time and is not yet
functional.

llvm-svn: 241022

llvm-svn: 236540

llvm-svn: 235360

llvm-svn: 232395

llvm-svn: 231412

llvm-svn: 227340

Summary:
V8->V9:
- cleanup tests

V7->V8:
- addressed feedback from David:
- switched to range-based 'for' loops
- fixed formatting of tests

V6->V7:
- rebased and adjusted AsmPrinter args
- CamelCased .td, fixed formatting, cleaned up names, removed unused patterns
- diffstat: 3 files changed, 203 insertions(+), 227 deletions(-)

V5->V6:
- addressed feedback from Chandler:
- reinstated full verbose standard banner in all files
- fixed variables that were not in CamelCase
- fixed names of #ifdef in header files
- removed redundant braces in if/else chains with single statements
- fixed comments
- removed trailing empty line
- dropped debug annotations from tests
- diffstat of these changes:
  46 files changed, 456 insertions(+), 469 deletions(-)

V4->V5:
- fix setLoadExtAction() interface
- clang-formated all where it made sense

V3->V4:
- added CODE_OWNERS entry for BPF backend

V2->V3:
- fix metadata in tests

V1->V2:
- addressed feedback from Tom and Matt
- removed top level change to configure (now everything via 'experimental-backend')
- reworked error reporting via DiagnosticInfo (similar to R600)
- added few more tests
- added cmake build
- added Triple::bpf
- tested on linux and darwin

V1 cover letter:
---------------------
recently linux gained "universal in-kernel virtual machine" which is called
eBPF or extended BPF. The name comes from "Berkeley Packet Filter", since
new instruction set is based on it.
This patch adds a new backend that emits extended BPF instruction set.

The concept and development are covered by the following articles:
http://lwn.net/Articles/599755/
http://lwn.net/Articles/575531/
http://lwn.net/Articles/603983/
http://lwn.net/Articles/606089/
http://lwn.net/Articles/612878/

One of use cases: dtrace/systemtap alternative.

bpf syscall manpage:
https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=b4fc1a460f3017e958e6a8ea560ea0afd91bf6fe

instruction set description and differences vs classic BPF:
http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/Documentation/networking/filter.txt



Short summary of instruction set:
- 64-bit registers
  R0      - return value from in-kernel function, and exit value for BPF program
  R1 - R5 - arguments from BPF program to in-kernel function
  R6 - R9 - callee saved registers that in-kernel function will preserve
  R10     - read-only frame pointer to access stack
- two-operand instructions like +, -, *, mov, load/store
- implicit prologue/epilogue (invisible stack pointer)
- no floating point, no simd

Short history of extended BPF in kernel:
interpreter in 3.15, x64 JIT in 3.16, arm64 JIT, verifier, bpf syscall in 3.18, more to come in the future.

It's a very small and simple backend.
There is no support for global variables, arbitrary function calls, floating point, varargs,
exceptions, indirect jumps, arbitrary pointer arithmetic, alloca, etc.
From C front-end point of view it's very restricted. It's done on purpose, since kernel
rejects all programs that it cannot prove safe. It rejects programs with loops
and with memory accesses via arbitrary pointers. When kernel accepts the program it is
guaranteed that program will terminate and will not crash the kernel.

This patch implements all 'must have' bits. There are several things on TODO list,
so this is not the end of development.
Most of the code is a boiler plate code, copy-pasted from other backends.
Only odd things are lack or < and <= instructions, specialized load_byte intrinsics
and 'compare and goto' as single instruction.
Current instruction set is fixed, but more instructions can be added in the future.

Signed-off-by: Alexei Starovoitov <alexei.starovoitov@gmail.com>

Subscribers: majnemer, chandlerc, echristo, joerg, pete, rengolin, kristof.beyls, arsenm, t.p.northover, tstellarAMD, aemerson, llvm-commits

Differential Revision: http://reviews.llvm.org/D6494

llvm-svn: 227008

As agreed with Richard Sandiford, I'm taking over code ownership
for the SystemZ back end from him.

llvm-svn: 224535

llvm-svn: 224088

I apparently fail at the alphabet, E is not after G, and G isn't even
close to C. Sorry for the noise.

llvm-svn: 223990