[Qemu-devel] [RFC v2 10/24] riscv: tcg-target: Add the relocation functions

[Alistair Francis]

Signed-off-by: Alistair Francis <alistair.fran...@wdc.com>
Signed-off-by: Michael Clark <m...@sifive.com>
---
 tcg/riscv/tcg-target.inc.c | 51 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 51 insertions(+)

diff --git a/tcg/riscv/tcg-target.inc.c b/tcg/riscv/tcg-target.inc.c
index ca7ae8939a..9c48679f11 100644
--- a/tcg/riscv/tcg-target.inc.c
+++ b/tcg/riscv/tcg-target.inc.c
@@ -383,6 +383,57 @@ static void tcg_out_opc_jump(TCGContext *s, RISCVInsn opc,
     tcg_out32(s, encode_uj(opc, rd, imm));
 }
 
+/*
+ * Relocations
+ */
+
+static void reloc_sbimm12(tcg_insn_unit *code_ptr, tcg_insn_unit *target)
+{
+    intptr_t offset = (intptr_t)target - (intptr_t)code_ptr;
+    tcg_debug_assert(offset == sextract32(offset, 1, 12) << 1);
+
+    code_ptr[0] |= encode_sbimm12(offset);
+}
+
+static void reloc_jimm20(tcg_insn_unit *code_ptr, tcg_insn_unit *target)
+{
+    intptr_t offset = (intptr_t)target - (intptr_t)code_ptr;
+    tcg_debug_assert(offset == sextract32(offset, 1, 20) << 1);
+
+    code_ptr[0] |= encode_ujimm12(offset);
+}
+
+static void reloc_call(tcg_insn_unit *code_ptr, tcg_insn_unit *target)
+{
+    intptr_t offset = (intptr_t)target - (intptr_t)code_ptr;
+    tcg_debug_assert(offset == (int32_t)offset);
+
+    int32_t hi20 = ((offset + 0x800) >> 12) << 12;
+    int32_t lo12 = offset - hi20;
+
+    code_ptr[0] |= encode_uimm20(hi20);
+    code_ptr[1] |= encode_imm12(lo12);
+}
+
+static void patch_reloc(tcg_insn_unit *code_ptr, int type,
+                        intptr_t value, intptr_t addend)
+{
+    tcg_debug_assert(addend == 0);
+    switch (type) {
+    case R_RISCV_BRANCH:
+        reloc_sbimm12(code_ptr, (tcg_insn_unit *)value);
+        break;
+    case R_RISCV_JAL:
+        reloc_jimm20(code_ptr, (tcg_insn_unit *)value);
+        break;
+    case R_RISCV_CALL:
+        reloc_call(code_ptr, (tcg_insn_unit *)value);
+        break;
+    default:
+        tcg_abort();
+    }
+}
+
 void tb_target_set_jmp_target(uintptr_t tc_ptr, uintptr_t jmp_addr,
                               uintptr_t addr)
 {
-- 
2.19.1