[clang] [compiler-rt] [llvm] [XRay][RISCV] RISCV support for XRay (PR #117368)

[Jessica Clarke via cfe-commits]

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@@ -0,0 +1,296 @@
+//===-- xray_riscv.cpp ----------------------------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This file is a part of XRay, a dynamic runtime instrumentation system.
+//
+// Implementation of riscv-specific routines (32- and 64-bit).
+//
+//===----------------------------------------------------------------------===//
+#include "sanitizer_common/sanitizer_common.h"
+#include "xray_defs.h"
+#include "xray_interface_internal.h"
+#include <atomic>
+
+namespace __xray {
+
+// The machine codes for some instructions used in runtime patching.
+enum PatchOpcodes : uint32_t {
+  PO_ADDI = 0x00000013, // addi rd, rs1, imm
+  PO_ADD = 0x00000033,  // add rd, rs1, rs2
+  PO_SW = 0x00002023,   // sw rt, base(offset)
+  PO_SD = 0x00003023,   // sd rt, base(offset)
+  PO_LUI = 0x00000037,  // lui rd, imm
+  PO_ORI = 0x00006013,  // ori rd, rs1, imm
+  PO_OR = 0x00006033,   // or rd, rs1, rs2
+  PO_SLLI = 0x00001013, // slli rd, rs, shamt
+  PO_SRLI = 0x00005013, // srli rd, rs, shamt
+  PO_JALR = 0x00000067, // jalr rs
+  PO_LW = 0x00002003,   // lw rd, base(offset)
+  PO_LD = 0x00003003,   // ld rd, base(offset)
+  PO_J = 0x0000006f,    // jal #n_bytes
----------------
jrtc27 wrote:

That's a bit misleading; JAL uses imm[0] to instead be imm[20], but this makes it look like the encoding puts the number of bytes in rather than the number of 16-bit parcels. I'd just go with `jal imm`.

https://github.com/llvm/llvm-project/pull/117368