tls: fix local-exec addresses and external symbols

Preserve symbolic offsets when materializing i386 TLS addresses, generate ARM64 TLS addresses from the thread pointer, and carry RISC-V addends on both halves of the TPREL relocation pair. Keep undefined ELF TLS symbols typed as STT_TLS so objects produced by TCC can be linked by the system linker. Extend the TLS regression coverage for narrow signed and unsigned accesses, address-taking, runtime indexing, thread isolation, large RISC-V offsets, unsupported runtimes, and external TLS definitions.
2026-11-04 21:26:36 +08:00 · 2026-07-10 23:58:23 +09:00 · 2026-07-10 23:58:23 +09:00 · 97a6d8c75f
commit 97a6d8c75f
parent 04206d2903
10 changed files with 165 additions and 48 deletions
--- a/arm64-gen.c
+++ b/arm64-gen.c
@ -468,20 +468,8 @@ static void arm64_strv(int sz_, int dst, int bas, uint64_t off)
    }
 }

-static void arm64_sym(int r, Sym *sym, unsigned long addend)
+static void arm64_add_offset(int r, unsigned long addend)
 {
-#ifdef TCC_TARGET_PE
-    /* PE links symbol addresses directly; there is no ELF-style GOT here. */
-    greloca(cur_text_section, sym, ind, R_AARCH64_ADR_PREL_PG_HI21, 0);
-    o(ARM64_ADRP | r);            // adrp xr, #sym
-    greloca(cur_text_section, sym, ind, R_AARCH64_ADD_ABS_LO12_NC, 0);
-    o(ARM64_ADD_IMM | ARM64_SF(1) | ARM64_RN(r) | r); // add xr, xr, #sym
-#else
-    greloca(cur_text_section, sym, ind, R_AARCH64_ADR_GOT_PAGE, 0);
-    o(ARM64_ADRP | r);            // adrp xr, #sym
-    greloca(cur_text_section, sym, ind, R_AARCH64_LD64_GOT_LO12_NC, 0);
-    o(ARM64_LDR_X | ARM64_RN(r) | r); // ld xr,[xr, #sym]
-#endif
    if (addend) {
        // add xr, xr, #addend
 	if (addend & 0xffful)
@ -504,17 +492,35 @@ static void arm64_sym(int r, Sym *sym, unsigned long addend)
    }
 }

+static void arm64_sym(int r, Sym *sym, unsigned long addend)
+{
+#ifdef TCC_TARGET_PE
+    /* PE links symbol addresses directly; there is no ELF-style GOT here. */
+    greloca(cur_text_section, sym, ind, R_AARCH64_ADR_PREL_PG_HI21, 0);
+    o(ARM64_ADRP | r);            // adrp xr, #sym
+    greloca(cur_text_section, sym, ind, R_AARCH64_ADD_ABS_LO12_NC, 0);
+    o(ARM64_ADD_IMM | ARM64_SF(1) | ARM64_RN(r) | r); // add xr, xr, #sym
+#else
+    greloca(cur_text_section, sym, ind, R_AARCH64_ADR_GOT_PAGE, 0);
+    o(ARM64_ADRP | r);            // adrp xr, #sym
+    greloca(cur_text_section, sym, ind, R_AARCH64_LD64_GOT_LO12_NC, 0);
+    o(ARM64_LDR_X | ARM64_RN(r) | r); // ld xr,[xr, #sym]
+#endif
+    arm64_add_offset(r, addend);
+}
+
 static void arm64_load_cmp(int r, SValue *sv);

-static void arm64_tls_x30(SValue *sv)
+static void arm64_tls_sym(int r, Sym *sym, unsigned long addend)
 {
-    o(0xd53bd05e); /* mrs x30, tpidr_el0 */
-    greloca(cur_text_section, sv->sym, ind, R_AARCH64_TLSLE_ADD_TPREL_HI12, 0);
-    /* add x30, x30, #0, lsl #12 */
-    o(ARM64_ADD_IMM | ARM64_SF(1) | ARM64_SH(1) | ARM64_RN(30) | ARM64_RD(30));
-    greloca(cur_text_section, sv->sym, ind, R_AARCH64_TLSLE_ADD_TPREL_LO12, 0);
-    /* add x30, x30, #0 */
-    o(ARM64_ADD_IMM | ARM64_SF(1) | ARM64_RN(30) | ARM64_RD(30));
+    o(0xd53bd040 | r); /* mrs xr, tpidr_el0 */
+    greloca(cur_text_section, sym, ind, R_AARCH64_TLSLE_ADD_TPREL_HI12, 0);
+    /* add xr, xr, #0, lsl #12 */
+    o(ARM64_ADD_IMM | ARM64_SF(1) | ARM64_SH(1) | ARM64_RN(r) | ARM64_RD(r));
+    greloca(cur_text_section, sym, ind, R_AARCH64_TLSLE_ADD_TPREL_LO12, 0);
+    /* add xr, xr, #0 */
+    o(ARM64_ADD_IMM | ARM64_SF(1) | ARM64_RN(r) | ARM64_RD(r));
+    arm64_add_offset(r, addend);
 }

 ST_FUNC void load(int r, SValue *sv)
@ -537,7 +543,9 @@ ST_FUNC void load(int r, SValue *sv)
    if (svr == (VT_CONST | VT_LVAL)) {
 	uint64_t i = sv->c.i;

-	if (sv->sym)
+	if (sv->sym && (sv->sym->type.t & VT_TLS))
+            arm64_tls_sym(30, sv->sym, 0);
+        else if (sv->sym)
            arm64_sym(30, sv->sym, // use x30 for address
 	              arm64_check_offset(0, arm64_type_size(svtt), i));
 	else
@ -564,7 +572,7 @@ ST_FUNC void load(int r, SValue *sv)

    if (svr == (VT_CONST | VT_LVAL | VT_SYM)) {
        if (sv->sym->type.t & VT_TLS)
-            arm64_tls_x30(sv);
+            arm64_tls_sym(30, sv->sym, 0);
        else
        arm64_sym(30, sv->sym, // use x30 for address
 		  arm64_check_offset(0, arm64_type_size(svtt), svcoff));
@ -578,6 +586,9 @@ ST_FUNC void load(int r, SValue *sv)
    }

    if (svr == (VT_CONST | VT_SYM)) {
+        if (sv->sym->type.t & VT_TLS)
+            arm64_tls_sym(intr(r), sv->sym, svcul);
+        else
            arm64_sym(intr(r), sv->sym, svcul);
        return;
    }
@ -659,7 +670,7 @@ ST_FUNC void store(int r, SValue *sv)
    if (svr == (VT_CONST | VT_LVAL)) {
 	uint64_t i = sv->c.i;
 	if (sv->sym && (sv->sym->type.t & VT_TLS))
-            arm64_tls_x30(sv);
+            arm64_tls_sym(30, sv->sym, 0);
        else
 	if (sv->sym)
            arm64_sym(30, sv->sym, // use x30 for address
@ -686,15 +697,7 @@ ST_FUNC void store(int r, SValue *sv)

    if (svr == (VT_CONST | VT_LVAL | VT_SYM)) {
        if (sv->sym->type.t & VT_TLS) {
-            o(0xd53bd05e); /* mrs x30, tpidr_el0 */
-            greloca(cur_text_section, sv->sym, ind,
-                    R_AARCH64_TLSLE_ADD_TPREL_HI12, 0);
-            o(ARM64_ADD_IMM | ARM64_SF(1) | ARM64_SH(1) |
-              ARM64_RN(30) | ARM64_RD(30)); /* add x30, x30, #0, lsl #12 */
-            greloca(cur_text_section, sv->sym, ind,
-                    R_AARCH64_TLSLE_ADD_TPREL_LO12, 0);
-            o(ARM64_ADD_IMM | ARM64_SF(1) |
-              ARM64_RN(30) | ARM64_RD(30)); /* add x30, x30, #0 */
+            arm64_tls_sym(30, sv->sym, 0);
            if (IS_FREG(r))
                arm64_strv(arm64_type_size(svtt), fltr(r), 30, svcoff);
            else
--- a/i386-gen.c
+++ b/i386-gen.c
@ -354,7 +354,7 @@ ST_FUNC void load(int r, SValue *sv)
    } else {
        if ((fr & VT_SYM) && (sv->sym->type.t & VT_TLS)) {
            oad(0x058b65 | REG_VALUE(r) << 19, 0); /* mov gs:0,r */
-            oad(0xC081 | REG_VALUE(r) << 8, 0); /* add tpoffs,r */
+            oad(0xC081 | REG_VALUE(r) << 8, fc); /* add tpoffs,r */
            greloc(cur_text_section, sv->sym, ind - 4, R_386_TLS_LE);
 #if defined CONFIG_TCC_PIC
        } else if ((fr & (VT_VALMASK|VT_SYM)) == (VT_CONST|VT_SYM)) {
--- a/riscv64-gen.c
+++ b/riscv64-gen.c
@ -186,10 +186,8 @@ static int load_symofs(int r, SValue *sv, int forstore, int *new_fc)
                    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);
+                    R_RISCV_TPREL_LO12_I, sv->c.i);
            EI(0x13, 0, rr, rr, 0); // addi RR, RR, 0 %tprel_lo(sym)
-	    if (fc)
-                EI(0x13, 0, rr, rr, fc); // addi RR, RR, fc
            ER(0x33, 0, rr, rr, 4, 0); // add RR, RR, tp
            *new_fc = 0;
            return rr;
--- a/tccelf.c
+++ b/tccelf.c
@ -205,7 +205,9 @@ ST_FUNC void tccelf_end_file(TCCState *s1)
 #ifndef TCC_TARGET_PE
            if (sym_bind == STB_GLOBAL && s1->output_type == TCC_OUTPUT_OBJ) {
                /* undefined symbols with STT_FUNC are confusing gnu ld when
-                   linking statically to STT_GNU_IFUNC */
+                   linking statically to STT_GNU_IFUNC.  Keep TLS typed,
+                   otherwise gnu ld rejects non-TLS refs to TLS definitions. */
+                if (sym_type != STT_TLS)
                    sym_type = STT_NOTYPE;
            }
 #endif
--- a/tests/tests2/144_tls.c
+++ b/tests/tests2/144_tls.c
@ -6,6 +6,11 @@
 typedef enum { tls_a, tls_b, tls_c } tls_enum_type;
 typedef struct { int tls_d, tls_e, tls_f; } tls_struct_type;

+typedef struct {
+    int *init;
+    signed short *element;
+} tls_address_type;
+
 __thread char tls_char = 42;
 __thread short tls_short = 43;
 __thread int tls_init = 44;
@ -17,6 +22,41 @@ __thread long double tls_long_double = 48.0;
 __thread int *tls_ptr = (int *)49;
 __thread tls_enum_type tls_enum = tls_b;
 __thread tls_struct_type tls_struct = { 50, 51, 52 };
+__thread signed char tls_signed_char = -5;
+__thread unsigned char tls_unsigned_char = 250;
+__thread signed short tls_signed_short = -1234;
+__thread unsigned short tls_unsigned_short = 60000;
+__thread signed short tls_array[4] = { -1000, 2000, -3000, 4000 };
+
+#if defined __riscv && __riscv_xlen == 64
+typedef struct {
+    char padding[4096];
+    int value;
+} tls_large_type;
+
+__thread tls_large_type tls_large = { { 0 }, 123456 };
+#endif
+
+static int check_extra(int changed)
+{
+    volatile int index = 2;
+
+    if (changed)
+        return tls_signed_char != -7 || tls_unsigned_char != 42
+            || tls_signed_short != -2222 || tls_unsigned_short != 12345
+            || tls_array[1] != 2222 || tls_array[index] != -3333;
+
+    if (tls_signed_char != -5 || tls_unsigned_char != 250
+        || tls_signed_short != -1234 || tls_unsigned_short != 60000
+        || tls_array[1] != 2000 || tls_array[index] != -3000)
+        return 1;
+
+#if defined __riscv && __riscv_xlen == 64
+    if (tls_large.value != 123456)
+        return 1;
+#endif
+    return 0;
+}

 static int check(void)
 {
@ -40,9 +80,18 @@ static int check(void)

 static void *thread_func(void *arg)
 {
-    (void)arg;
+    tls_address_type *main_addresses = arg;
+    int *init_address = &tls_init;
+    signed short *element_address = &tls_array[1];
+    volatile int index = 2;
    long errors = check();

+    if (init_address == main_addresses->init
+        || element_address == main_addresses->element
+        || *init_address != 44 || *element_address != 2000
+        || tls_array[index] != -3000 || check_extra(0))
+        errors = 1;
+
    tls_char = 10;
    tls_short = 20;
    tls_init = 30;
@ -56,6 +105,12 @@ static void *thread_func(void *arg)
    tls_struct.tls_d = 100;
    tls_struct.tls_e = 110;
    tls_struct.tls_f = 120;
+    *element_address = 2222;
+    tls_array[index] = -3333;
+    tls_signed_char = -7;
+    tls_unsigned_char = 42;
+    tls_signed_short = -2222;
+    tls_unsigned_short = 12345;

    CHECK(tls_char, "%d", 10);
    CHECK(tls_short, "%d", 20);
@ -71,6 +126,10 @@ static void *thread_func(void *arg)
    CHECK(tls_struct.tls_e, "%d", 110);
    CHECK(tls_struct.tls_f, "%d", 120);

+    if (*init_address != 30 || *element_address != 2222
+        || tls_array[index] != -3333 || check_extra(1))
+        errors = 1;
+
    return (void *)errors;
 }

@ -79,9 +138,20 @@ int main()
    pthread_t t;
    void *ret;
    int errors = check();
+    tls_address_type addresses = { &tls_init, &tls_array[1] };

-    pthread_create(&t, NULL, thread_func, NULL);
+    if (*addresses.init != 44 || *addresses.element != 2000
+        || check_extra(0))
+        errors = 1;
+
+    pthread_create(&t, NULL, thread_func, &addresses);
    pthread_join(t, &ret);

-    return (ret ? 1 : 0) | errors | check();
+    errors |= (ret ? 1 : 0) | check();
+    if (*addresses.init != 44 || *addresses.element != 2000
+        || check_extra(0))
+        errors = 1;
+
+    printf("errors: %d\n", errors);
+    return errors;
 }
--- a/tests/tests2/144_tls.expect
+++ b/tests/tests2/144_tls.expect
@ -50,3 +50,4 @@
 50
 51
 52
+errors: 0
--- a/tests/tests2/146+_tls_extern.c
+++ b/tests/tests2/146+_tls_extern.c
@ -0,0 +1,2 @@
+__thread signed short extern_tls_short = 1234;
+__thread float extern_tls_float = 1.5f;
--- a/tests/tests2/146_tls_extern.c
+++ b/tests/tests2/146_tls_extern.c
@ -0,0 +1,22 @@
+#include <stdio.h>
+
+extern __thread signed short extern_tls_short;
+extern __thread float extern_tls_float;
+
+int main(void)
+{
+    int errors = 0;
+
+    if (extern_tls_short != 1234 || extern_tls_float != 1.5f)
+        errors = 1;
+
+    extern_tls_short = -2222;
+    extern_tls_float = 2.5f;
+    extern_tls_float += 1.0f;
+
+    if (extern_tls_short != -2222 || extern_tls_float != 3.5f)
+        errors = 1;
+
+    printf("extern tls errors: %d\n", errors);
+    return errors;
+}
--- a/tests/tests2/146_tls_extern.expect
+++ b/tests/tests2/146_tls_extern.expect
@ -0,0 +1 @@
+extern tls errors: 0
--- a/tests/tests2/Makefile
+++ b/tests/tests2/Makefile
@ -15,6 +15,9 @@ endif
 ifeq (,$(filter i386,$(ARCH)))
 SKIP += 98_al_ax_extend.test 99_fastcall.test
 endif
+ifeq (,$(filter x86_64 riscv64 arm64 i386,$(ARCH)))
+ SKIP += 146_tls_extern.test # TLS only implemented on these architectures
+endif
 ifeq (,$(filter i386 x86_64,$(ARCH)))
 SKIP += 85_asm-outside-function.test # x86 asm
 SKIP += 127_asm_goto.test    # hardcodes x86 asm
@ -39,6 +42,9 @@ endif
 ifeq (-$(findstring gcc,$(CC))-,--)
 SKIP += $(patsubst %.expect,%.test,$(GEN-ALWAYS))
 endif
+ifeq ($(CC_NAME),tcc)
+ SKIP += 146_tls_extern.test # needs an external system linker
+endif
 ifeq (-$(CONFIG_WIN32)-$(CONFIG_i386)$(CONFIG_arm)-,--yes-)
 SKIP += 95_bitfields%.test # type_align is different on 32bit-non-windows
 endif
@ -47,19 +53,22 @@ ifeq (-$(CONFIG_WIN32)-,-yes-)
 SKIP += 114_bound_signal.test # No pthread support
 SKIP += 117_builtins.test # win32 port doesn't define __builtins
 SKIP += 124_atomic_counter.test # No pthread support
- SKIP += 144_tls.test # No pthread support
+ SKIP += 144_tls.test 146_tls_extern.test # TLS runtime not supported
 endif
 ifneq (,$(filter OpenBSD FreeBSD NetBSD,$(TARGETOS)))
 SKIP += 106_versym.test # no pthread_condattr_setpshared
 SKIP += 114_bound_signal.test # libc problem signal/fork
 SKIP += 116_bound_setjmp2.test # No TLS_FUNC/TLS_VAR in bcheck.c
- SKIP += 144_tls.test # No tls support
+ SKIP += 144_tls.test 146_tls_extern.test # No tls support
+endif
+ifeq ($(TARGETOS),DragonFly)
+ SKIP += 144_tls.test 146_tls_extern.test # TLS runtime not supported
 endif
 ifeq ($(CONFIG_OSX),yes)
- SKIP += 144_tls.test # TLS runtime not supported on Mach-O
+ SKIP += 144_tls.test 146_tls_extern.test # TLS runtime not supported on Mach-O
 endif
 ifeq (-$(ARCH)-,-arm-)
- SKIP += 144_tls.test # doesn't work currently
+ SKIP += 144_tls.test 146_tls_extern.test # doesn't work currently
 endif
 ifneq (-$(ARCH)-,-arm64-)
 SKIP += 138_arm64_encoding.test
@ -122,6 +131,15 @@ GEN-ALWAYS =
 144_tls.test: FLAGS += -pthread
 144_tls.test: NORUN = true

+# Verify that undefined TLS symbols in TCC objects work with the system linker.
+146_tls_extern.test: NORUN = true
+146_tls_extern.test: T1 = \
+	$(TCC) -c $1 -o 146_tls_extern-main.o && \
+	$(TCC) -c $(subst 146,146+,$1) -o 146_tls_extern-def.o && \
+	$(CC) -no-pie -Wl,-z,noexecstack 146_tls_extern-main.o \
+		146_tls_extern-def.o -o $(basename $@).exe && \
+	./$(basename $@).exe
+
 112_backtrace.test: FLAGS += -dt -b
 112_backtrace.test 113_btdll.test 126_bound_global.test: FILTER += \
    -e 's;[0-9A-Fa-fx]\{5,\};........;g' \
@ -204,4 +222,4 @@ $(sort $(GEN-ALWAYS) $(UPDATE)) : force
 force:

 clean :
-	rm -f fred.txt *.output *.exe *.dll *.so *.def $(GEN-ALWAYS)
+	rm -f fred.txt *.output *.o *.exe *.dll *.so *.def $(GEN-ALWAYS)