[all-commits] [llvm/llvm-project] f9fd00: [XRay][AArch64] Suppport __xray_customevent/__xray...

[Fangrui Song via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: f9fd0062b60ee53055a7a6f97e4256bfe2c153ed
      https://github.com/llvm/llvm-project/commit/f9fd0062b60ee53055a7a6f97e4256bfe2c153ed
  Author: Fangrui Song <i at maskray.me>
  Date:   2023-06-23 (Fri, 23 Jun 2023)

  Changed paths:
    M compiler-rt/lib/xray/xray_AArch64.cpp
    M compiler-rt/lib/xray/xray_trampoline_AArch64.S
    M compiler-rt/test/xray/TestCases/Posix/custom-event-logging.cpp
    M compiler-rt/test/xray/TestCases/Posix/typed-event-logging.cpp
    M llvm/lib/CodeGen/SelectionDAG/FastISel.cpp
    M llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
    M llvm/lib/Target/AArch64/AArch64AsmPrinter.cpp
    M llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
    A llvm/test/CodeGen/AArch64/xray-custom-log.ll

  Log Message:
  -----------
  [XRay][AArch64] Suppport __xray_customevent/__xray_typedevent

`__xray_customevent` and `__xray_typedevent` are built-in functions in Clang.
With -fxray-instrument, they are lowered to intrinsics llvm.xray.customevent and
llvm.xray.typedevent, respectively. These intrinsics are then lowered to
TargetOpcode::{PATCHABLE_EVENT_CALL,PATCHABLE_TYPED_EVENT_CALL}. The target is
responsible for generating a code sequence that calls either
`__xray_CustomEvent` (with 2 arguments) or `__xray_TypedEvent` (with 3
arguments).

Before patching, the code sequence is prefixed by a branch instruction that
skips the rest of the code sequence. After patching
(compiler-rt/lib/xray/xray_AArch64.cpp), the branch instruction becomes a NOP
and the function call will take effects.

This patch implements the lowering process for
{PATCHABLE_EVENT_CALL,PATCHABLE_TYPED_EVENT_CALL} and implements the runtime.

```
// Lowering of PATCHABLE_EVENT_CALL
.Lxray_sled_N:
  b  #24
  stp x0, x1, [sp, #-16]!
  x0 = reg of op0
  x1 = reg of op1
  bl __xray_CustomEvent
  ldrp x0, x1, [sp], #16
```

As a result, two updated tests in compiler-rt/test/xray/TestCases/Posix/ now
pass on AArch64.

Reviewed By: peter.smith

Differential Revision: https://reviews.llvm.org/D153320