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

[Craig Topper via cfe-commits]

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@@ -0,0 +1,96 @@
+//===-- xray_trampoline_riscv_common.s --------------------------*- ASM -*-===//
+//
+// 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.
+//
+// This implements the trampolines code shared between riscv32 and riscv64.
+//
+//===----------------------------------------------------------------------===//
+
+#include "../builtins/assembly.h"
+
+	.text
+	.p2align 2
+	.global ASM_SYMBOL(__xray_FunctionEntry)
+	ASM_TYPE_FUNCTION(__xray_FunctionEntry)
+ASM_SYMBOL(__xray_FunctionEntry):
+	CFI_STARTPROC
+        SAVE_ARG_REGISTERS
+
+	// Load the handler function pointer into a2
+	la	a2, ASM_SYMBOL(_ZN6__xray19XRayPatchedFunctionE)
+        LOAD_XLEN   a2, 0(a2)
+
+	// Handler address will be null if it is not set
+	beq	a2, x0, 1f
+
+	// If we reach here, we are tracing an event
+	// a0 already contains function id
+	// a1 = 0 means we are tracing an entry event
+	mv	a1, x0
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topperc wrote:

Use `li a1, 0`

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