From 11f5c6e1f9e35dbe44982a35ec5f4c7f3b8387c3 Mon Sep 17 00:00:00 2001
From: Meng Zhuo <mengzhuo@iscas.ac.cn>
Date: Tue, 12 May 2026 19:57:35 +0800
Subject: [PATCH] feat(riscv64): add TLS Local Exec code generation and linker
 relocations

---
 riscv64-gen.c         | 13 +++++++++++++
 riscv64-link.c        | 31 +++++++++++++++++++++++++++++++
 tests/tests2/Makefile |  2 +-
 3 files changed, 45 insertions(+), 1 deletion(-)

diff --git a/riscv64-gen.c b/riscv64-gen.c
index 6ded4c52..8084c6b6 100644
--- a/riscv64-gen.c
+++ b/riscv64-gen.c
@@ -179,6 +179,19 @@ static int load_symofs(int r, SValue *sv, int forstore, int *new_fc)
     if (sv->r & VT_SYM) {
         Sym label = {0};
         assert(v == VT_CONST);
+        if (sv->sym->type.t & VT_TLS) {
+            /* TLS Local Exec model: lui + addi + add tp */
+            rr = is_ireg(r) ? ireg(r) : 5;
+            greloca(cur_text_section, sv->sym, ind,
+                    R_RISCV_TPREL_HI20, sv->c.i);
+            o(0x37 | (rr << 7));  // lui RR, 0 %tprel_hi(sym)
+            greloca(cur_text_section, sv->sym, ind,
+                    R_RISCV_TPREL_LO12_I, 0);
+            EI(0x13, 0, rr, rr, 0); // addi RR, RR, 0 %tprel_lo(sym)
+            ER(0x33, 0, rr, rr, 4, 0); // add RR, RR, tp
+            *new_fc = 0;
+            return rr;
+        }
         if (sv->sym->type.t & VT_STATIC) { // XXX do this per linker relax
             greloca(cur_text_section, sv->sym, ind,
                     R_RISCV_PCREL_HI20, sv->c.i);
diff --git a/riscv64-link.c b/riscv64-link.c
index 0d2ad2a4..625cccfd 100644
--- a/riscv64-link.c
+++ b/riscv64-link.c
@@ -53,6 +53,8 @@ ST_FUNC int code_reloc (int reloc_type)
     case R_RISCV_64:
     case R_RISCV_SET_ULEB128:
     case R_RISCV_SUB_ULEB128:
+    case R_RISCV_TPREL_HI20:
+    case R_RISCV_TPREL_LO12_I:
         return 0;
 
     case R_RISCV_CALL_PLT:
@@ -101,6 +103,10 @@ ST_FUNC int gotplt_entry_type (int reloc_type)
 
     case R_RISCV_GOT_HI20:
         return ALWAYS_GOTPLT_ENTRY;
+
+    case R_RISCV_TPREL_HI20:
+    case R_RISCV_TPREL_LO12_I:
+        return NO_GOTPLT_ENTRY;
     }
     return -1;
 }
@@ -399,6 +405,31 @@ ST_FUNC void relocate(TCCState *s1, ElfW_Rel *rel, int type, unsigned char *ptr,
            RELATIVE relocations from object files. */
         return;
 
+    case R_RISCV_TPREL_HI20:
+    case R_RISCV_TPREL_LO12_I: {
+        addr_t tls_start = 0;
+        int i;
+        for (i = 1; i < s1->nb_sections; i++) {
+            Section *s = s1->sections[i];
+            if (s->sh_flags & SHF_TLS && s->sh_size) {
+                if (!tls_start || s->sh_addr < tls_start)
+                    tls_start = s->sh_addr;
+            }
+        }
+        int64_t tp_offset = val - tls_start;
+        if (type == R_RISCV_TPREL_HI20) {
+            off64 = (int64_t)(tp_offset + 0x800) >> 12;
+            if ((off64 + ((uint64_t)1 << 20)) >> 21)
+                tcc_error_noabort("R_RISCV_TPREL_HI20 relocation failed");
+            write32le(ptr, (read32le(ptr) & 0xfff)
+                           | ((off64 & 0xfffff) << 12));
+        } else {
+            write32le(ptr, (read32le(ptr) & 0xfffff)
+                           | (((tp_offset) & 0xfff) << 20));
+        }
+        return;
+    }
+
     default:
         fprintf(stderr, "FIXME: handle reloc type %x at %x [%p] to %x\n",
                 type, (unsigned)addr, ptr, (unsigned)val);
diff --git a/tests/tests2/Makefile b/tests/tests2/Makefile
index 0fd98687..f00906ac 100644
--- a/tests/tests2/Makefile
+++ b/tests/tests2/Makefile
@@ -19,7 +19,7 @@ ifeq (,$(filter i386 x86_64,$(ARCH)))
  SKIP += 85_asm-outside-function.test # x86 asm
  SKIP += 127_asm_goto.test    # hardcodes x86 asm
 endif
-ifeq (,$(filter x86_64,$(ARCH)))
+ifeq (,$(filter x86_64 riscv64,$(ARCH)))
  SKIP += 144_tls.test # TLS only implemented on x86_64 so far
 endif
 ifeq ($(CONFIG_backtrace),no)