diff options
| -rw-r--r-- | Misc/NEWS.d/next/Core and Builtins/2024-06-07-22-54-15.gh-issue-119726.D9EE-o.rst | 1 | ||||
| -rw-r--r-- | Tools/jit/_stencils.py | 20 |
2 files changed, 17 insertions, 4 deletions
diff --git a/Misc/NEWS.d/next/Core and Builtins/2024-06-07-22-54-15.gh-issue-119726.D9EE-o.rst b/Misc/NEWS.d/next/Core and Builtins/2024-06-07-22-54-15.gh-issue-119726.D9EE-o.rst new file mode 100644 index 0000000..595d8dd --- /dev/null +++ b/Misc/NEWS.d/next/Core and Builtins/2024-06-07-22-54-15.gh-issue-119726.D9EE-o.rst @@ -0,0 +1 @@ +JIT: Re-use trampolines on AArch64 when creating stencils. Patch by Diego Russo diff --git a/Tools/jit/_stencils.py b/Tools/jit/_stencils.py index 6e046df..c7c5ca1 100644 --- a/Tools/jit/_stencils.py +++ b/Tools/jit/_stencils.py @@ -181,6 +181,7 @@ class Stencil: body: bytearray = dataclasses.field(default_factory=bytearray, init=False) holes: list[Hole] = dataclasses.field(default_factory=list, init=False) disassembly: list[str] = dataclasses.field(default_factory=list, init=False) + trampolines: dict[str, int] = dataclasses.field(default_factory=dict, init=False) def pad(self, alignment: int) -> None: """Pad the stencil to the given alignment.""" @@ -189,14 +190,25 @@ class Stencil: self.disassembly.append(f"{offset:x}: {' '.join(['00'] * padding)}") self.body.extend([0] * padding) - def emit_aarch64_trampoline(self, hole: Hole) -> None: + def emit_aarch64_trampoline(self, hole: Hole, alignment: int) -> None: """Even with the large code model, AArch64 Linux insists on 28-bit jumps.""" - base = len(self.body) + assert hole.symbol is not None + reuse_trampoline = hole.symbol in self.trampolines + if reuse_trampoline: + # Re-use the base address of the previously created trampoline + base = self.trampolines[hole.symbol] + else: + self.pad(alignment) + base = len(self.body) where = slice(hole.offset, hole.offset + 4) instruction = int.from_bytes(self.body[where], sys.byteorder) instruction &= 0xFC000000 instruction |= ((base - hole.offset) >> 2) & 0x03FFFFFF self.body[where] = instruction.to_bytes(4, sys.byteorder) + + if reuse_trampoline: + return + self.disassembly += [ f"{base + 4 * 0:x}: d2800008 mov x8, #0x0", f"{base + 4 * 0:016x}: R_AARCH64_MOVW_UABS_G0_NC {hole.symbol}", @@ -225,6 +237,7 @@ class Stencil: ] ): self.holes.append(hole.replace(offset=base + 4 * i, kind=kind)) + self.trampolines[hole.symbol] = base def remove_jump(self, *, alignment: int = 1) -> None: """Remove a zero-length continuation jump, if it exists.""" @@ -300,8 +313,7 @@ class StencilGroup: in {"R_AARCH64_CALL26", "R_AARCH64_JUMP26", "ARM64_RELOC_BRANCH26"} and hole.value is HoleValue.ZERO ): - self.code.pad(alignment) - self.code.emit_aarch64_trampoline(hole) + self.code.emit_aarch64_trampoline(hole, alignment) self.code.holes.remove(hole) self.code.remove_jump(alignment=alignment) self.code.pad(alignment) |