[lld] [LLD] Add support for statically resolved vendor-specific RISCV relocations. (PR #169273)

[Sam Elliott via llvm-commits]

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@@ -0,0 +1,113 @@
+//===----------------------------------------------------------------------===//
+//
+// 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
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLD_ELF_ARCH_RISCVINTERNALRELOCATIONS_H
+#define LLD_ELF_ARCH_RISCVINTERNALRELOCATIONS_H
+
+#include "Relocations.h"
+#include "Symbols.h"
+
+namespace lld::elf {
+
+// Bit 8 of RelType is used to indicate linker-internal relocations that are
+// not vendor-specific.
+// These are internal relocation numbers for GP/X0 relaxation. They aren't part
+// of the psABI spec.
+constexpr uint32_t INTERNAL_R_RISCV_GPREL_I = 256;
+constexpr uint32_t INTERNAL_R_RISCV_GPREL_S = 257;
+constexpr uint32_t INTERNAL_R_RISCV_X0REL_I = 258;
+constexpr uint32_t INTERNAL_R_RISCV_X0REL_S = 259;
+
+// Bits 9 -> 31 of RelType are used to indicate vendor-specific relocations.
+constexpr uint32_t INTERNAL_RISCV_VENDOR_MASK = 0xFFFFFFFF << 9;
+constexpr uint32_t INTERNAL_RISCV_VENDOR_QUALCOMM = 1 << 9;
+constexpr uint32_t INTERNAL_RISCV_VENDOR_ANDES = 2 << 9;
+
+constexpr uint32_t INTERNAL_RISCV_QC_ABS20_U =
+    INTERNAL_RISCV_VENDOR_QUALCOMM | llvm::ELF::R_RISCV_QC_ABS20_U;
+constexpr uint32_t INTERNAL_RISCV_QC_E_BRANCH =
+    INTERNAL_RISCV_VENDOR_QUALCOMM | llvm::ELF::R_RISCV_QC_E_BRANCH;
+constexpr uint32_t INTERNAL_RISCV_QC_E_32 =
+    INTERNAL_RISCV_VENDOR_QUALCOMM | llvm::ELF::R_RISCV_QC_E_32;
+constexpr uint32_t INTERNAL_RISCV_QC_E_CALL_PLT =
+    INTERNAL_RISCV_VENDOR_QUALCOMM | llvm::ELF::R_RISCV_QC_E_CALL_PLT;
+
+constexpr uint32_t INTERNAL_RISCV_NDS_BRANCH_10 =
+    INTERNAL_RISCV_VENDOR_ANDES | llvm::ELF::R_RISCV_NDS_BRANCH_10;
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lenary wrote:

I wonder if we can reuse `RISCV_nonstandard.def` for defining these, but that's a nit we can revisit in the future.

https://github.com/llvm/llvm-project/pull/169273