LoongArch: Add support for TLS descriptors.

Add support for TLS descriptors on normal code model and extreme
code model.

Normal code model instruction sequence:
  -mno-explicit-relocs:
    la.tls.desc	$r4, s
    add.d	$r12, $r4, $r2
  -mexplicit-relocs:
    pcalau12i	$r4,%desc_pc_hi20(s)
    addi.d	$r4,$r4,%desc_pc_lo12(s)
    ld.d	$r1,$r4,%desc_ld(s)
    jirl	$r1,$r1,%desc_call(s)
    add.d	$r12, $r4, $r2

Extreme code model instruction sequence:
  -mno-explicit-relocs:
    la.tls.desc	$r4, $r12, s
    add.d	$r12, $r4, $r2
  -mexplicit-relocs:
    pcalau12i	$r4,%desc_pc_hi20(s)
    addi.d	$r12,$r0,%desc_pc_lo12(s)
    lu32i.d	$r12,%desc64_pc_lo20(s)
    lu52i.d	$r12,$r12,%desc64_pc_hi12(s)
    add.d	$r4,$r4,$r12
    ld.d	$r1,$r4,%desc_ld(s)
    jirl	$r1,$r1,%desc_call(s)
    add.d	$r12, $r4, $r2

The default is still traditional TLS model, but can be configured with
--with-tls={trad,desc}. The default can change to TLS descriptors once
libc and LLVM support this.

gcc/ChangeLog:

	* config.gcc: Add --with-tls option to change TLS flavor.
	* config/loongarch/genopts/loongarch.opt.in: Add -mtls-dialect to
	configure TLS flavor.
	* config/loongarch/loongarch-def.h (struct loongarch_target): Add
	tls_dialect.
	* config/loongarch/loongarch-driver.cc (la_driver_init): Add tls
	flavor.
	* config/loongarch/loongarch-opts.cc (loongarch_init_target): Add
	tls_dialect.
	(loongarch_config_target): Ditto.
	(loongarch_update_gcc_opt_status): Ditto.
	* config/loongarch/loongarch-opts.h (loongarch_init_target): Ditto.
	(TARGET_TLS_DESC): New define.
	* config/loongarch/loongarch.cc (loongarch_symbol_insns): Add TLS
	DESC instructions sequence length.
	(loongarch_legitimize_tls_address): New TLS DESC instruction sequence.
	(loongarch_option_override_internal): Add la_opt_tls_dialect.
	(loongarch_option_restore): Add la_target.tls_dialect.
	* config/loongarch/loongarch.md (@got_load_tls_desc<mode>): Normal
	code model for TLS DESC.
	(got_load_tls_desc_off64): Extreme cmode model for TLS DESC.
	* config/loongarch/loongarch.opt: Regenerate.
	* config/loongarch/loongarch.opt.urls: Ditto.
	* doc/invoke.texi: Add a description of the compilation option
	'-mtls-dialect={trad,desc}'.

gcc/testsuite/ChangeLog:

	* gcc.target/loongarch/cmodel-extreme-1.c: Add -mtls-dialect=trad.
	* gcc.target/loongarch/cmodel-extreme-2.c: Ditto.
	* gcc.target/loongarch/explicit-relocs-auto-tls-ld-gd.c: Ditto.
	* gcc.target/loongarch/explicit-relocs-medium-call36-auto-tls-ld-gd.c:
	Ditto.
	* gcc.target/loongarch/func-call-medium-1.c: Ditto.
	* gcc.target/loongarch/func-call-medium-2.c: Ditto.
	* gcc.target/loongarch/func-call-medium-3.c: Ditto.
	* gcc.target/loongarch/func-call-medium-4.c: Ditto.
	* gcc.target/loongarch/tls-extreme-macro.c: Ditto.
	* gcc.target/loongarch/tls-gd-noplt.c: Ditto.
	* gcc.target/loongarch/explicit-relocs-auto-extreme-tls-desc.c: New test.
	* gcc.target/loongarch/explicit-relocs-auto-tls-desc.c: New test.
	* gcc.target/loongarch/explicit-relocs-extreme-tls-desc.c: New test.
	* gcc.target/loongarch/explicit-relocs-tls-desc.c: New test.

Co-authored-by: Lulu Cheng <chenglulu@loongson.cn>
Co-authored-by: Xi Ruoyao <xry111@xry111.site>

9 files changed, 154 insertions, 14 deletions

diff --git a/gcc/config/loongarch/genopts/loongarch.opt.in b/gcc/config/loongarch/genopts/loongarch.opt.in
index a77893d..50ea47a 100644
--- a/gcc/config/loongarch/genopts/loongarch.opt.in
+++ b/gcc/config/loongarch/genopts/loongarch.opt.in
@@ -245,6 +245,20 @@ mpass-mrelax-to-as
 Driver Var(la_pass_mrelax_to_as) Init(HAVE_AS_MRELAX_OPTION)
 Pass -mrelax or -mno-relax option to the assembler.
 
+Enum
+Name(tls_type) Type(int)
+The possible TLS dialects:
+
+EnumValue
+Enum(tls_type) String(trad) Value(TLS_TRADITIONAL)
+
+EnumValue
+Enum(tls_type) String(desc) Value(TLS_DESCRIPTORS)
+
+mtls-dialect=
+Target RejectNegative Joined Enum(tls_type) Var(la_opt_tls_dialect) Init(M_OPT_UNSET) Save
+Specify TLS dialect.
+
 -param=loongarch-vect-unroll-limit=
 Target Joined UInteger Var(la_vect_unroll_limit) Init(6) IntegerRange(1, 64) Param
 Used to limit unroll factor which indicates how much the autovectorizer may
diff --git a/gcc/config/loongarch/loongarch-def.h b/gcc/config/loongarch/loongarch-def.h
index 0cbf947..60ce3e2 100644
--- a/gcc/config/loongarch/loongarch-def.h
+++ b/gcc/config/loongarch/loongarch-def.h
@@ -180,6 +180,7 @@ struct loongarch_target
   int cpu_arch;	    /* CPU_ */
   int cpu_tune;	    /* same */
   int cmodel;	    /* CMODEL_ */
+  int tls_dialect;  /* TLS_ */
 };
 
 /* CPU model */
@@ -193,6 +194,12 @@ enum {
   N_TUNE_TYPES	    = 5
 };
 
+/* TLS types.  */
+enum {
+  TLS_TRADITIONAL = 0,
+  TLS_DESCRIPTORS = 1
+};
+
 /* CPU model properties */
 extern loongarch_def_array<const char *, N_ARCH_TYPES>
   loongarch_cpu_strings;
diff --git a/gcc/config/loongarch/loongarch-driver.cc b/gcc/config/loongarch/loongarch-driver.cc
index 62658f5..8c4ed34 100644
--- a/gcc/config/loongarch/loongarch-driver.cc
+++ b/gcc/config/loongarch/loongarch-driver.cc
@@ -45,7 +45,7 @@ la_driver_init (int argc ATTRIBUTE_UNUSED, const char **argv ATTRIBUTE_UNUSED)
   /* Initialize all fields of la_target.  */
   loongarch_init_target (&la_target, M_OPT_UNSET, M_OPT_UNSET, M_OPT_UNSET,
 			 M_OPT_UNSET, M_OPT_UNSET, M_OPT_UNSET, M_OPT_UNSET,
-			 0, 0);
+			 M_OPT_UNSET, 0, 0);
   return "";
 }
 
diff --git a/gcc/config/loongarch/loongarch-opts.cc b/gcc/config/loongarch/loongarch-opts.cc
index e600f08..2a6fc41 100644
--- a/gcc/config/loongarch/loongarch-opts.cc
+++ b/gcc/config/loongarch/loongarch-opts.cc
@@ -144,6 +144,7 @@ void
 loongarch_init_target (struct loongarch_target *target,
 		       int cpu_arch, int cpu_tune, int fpu, int simd,
 		       int abi_base, int abi_ext, int cmodel,
+		       int tls_dialect,
 		       HOST_WIDE_INT isa_evolution,
 		       HOST_WIDE_INT isa_evolution_set)
 {
@@ -158,6 +159,7 @@ loongarch_init_target (struct loongarch_target *target,
   target->abi.base = abi_base;
   target->abi.ext = abi_ext;
   target->cmodel = cmodel;
+  target->tls_dialect = tls_dialect;
 }
 
 
@@ -179,7 +181,8 @@ loongarch_config_target (struct loongarch_target *target,
   obstack_init (&msg_obstack);
 
   struct {
-    int arch, tune, fpu, simd, abi_base, abi_ext, cmodel, abi_flt;
+    int arch, tune, fpu, simd, abi_base, abi_ext, cmodel,
+	tls_dialect, abi_flt;
   } constrained = {
       M_OPT_ABSENT (target->cpu_arch)	  ? 0 : 1,
       M_OPT_ABSENT (target->cpu_tune)	  ? 0 : 1,
@@ -188,6 +191,7 @@ loongarch_config_target (struct loongarch_target *target,
       M_OPT_ABSENT (target->abi.base)	  ? 0 : 1,
       M_OPT_ABSENT (target->abi.ext)	  ? 0 : 1,
       M_OPT_ABSENT (target->cmodel)	  ? 0 : 1,
+      M_OPT_ABSENT (target->tls_dialect)  ? 0 : 1,
       M_OPT_ABSENT (target->abi.base)	  ? 0 : 1,
   };
 
@@ -556,6 +560,9 @@ fallback:
       gcc_unreachable ();
     }
 
+  t.tls_dialect = constrained.tls_dialect ? target->tls_dialect
+	  : DEFAULT_TLS_TYPE;
+
   /* Cleanup and return.  */
   obstack_free (&msg_obstack, NULL);
   *target = t;
@@ -791,6 +798,9 @@ loongarch_update_gcc_opt_status (struct loongarch_target *target,
   /* status of -mcmodel */
   opts->x_la_opt_cmodel = target->cmodel;
 
+  /* status of -mtls-dialect */
+  opts->x_la_opt_tls_dialect = target->tls_dialect;
+
   /* status of -mfpu */
   opts->x_la_opt_fpu = target->isa.fpu;
 
diff --git a/gcc/config/loongarch/loongarch-opts.h b/gcc/config/loongarch/loongarch-opts.h
index 2d9f592..9844b27 100644
--- a/gcc/config/loongarch/loongarch-opts.h
+++ b/gcc/config/loongarch/loongarch-opts.h
@@ -39,6 +39,7 @@ void
 loongarch_init_target (struct loongarch_target *target,
 		       int cpu_arch, int cpu_tune, int fpu, int simd,
 		       int abi_base, int abi_ext, int cmodel,
+		       int tls_dialect,
 		       HOST_WIDE_INT isa_evolutions,
 		       HOST_WIDE_INT isa_evolutions_set);
 
@@ -105,6 +106,8 @@ struct loongarch_flags {
 #define TARGET_64BIT		  (la_target.isa.base == ISA_BASE_LA64)
 #define TARGET_ABI_LP64		  ABI_LP64_P(la_target.abi.base)
 
+#define TARGET_TLS_DESC		  (la_target.tls_dialect == TLS_DESCRIPTORS)
+
 #define ISA_HAS_LSX \
   (la_target.isa.simd == ISA_EXT_SIMD_LSX \
    || la_target.isa.simd == ISA_EXT_SIMD_LASX)
diff --git a/gcc/config/loongarch/loongarch.cc b/gcc/config/loongarch/loongarch.cc
index a69a203..cbc91c9 100644
--- a/gcc/config/loongarch/loongarch.cc
+++ b/gcc/config/loongarch/loongarch.cc
@@ -2031,7 +2031,7 @@ loongarch_symbol_insns (enum loongarch_symbol_type type, machine_mode mode)
 
     case SYMBOL_TLSGD:
     case SYMBOL_TLSLDM:
-      return 3;
+      return TARGET_TLS_DESC ? 4 : 3;
 
     case SYMBOL_PCREL64:
       return 5;
@@ -2933,24 +2933,43 @@ loongarch_call_tls_get_addr (rtx sym, enum loongarch_symbol_type type, rtx v0)
 static rtx
 loongarch_legitimize_tls_address (rtx loc)
 {
-  rtx dest, tp, tmp, tmp1, tmp2, tmp3;
+  rtx dest, tp, tmp, tmp1, tmp2, tmp3, a0;
   enum tls_model model = SYMBOL_REF_TLS_MODEL (loc);
   rtx_insn *insn;
 
   switch (model)
     {
     case TLS_MODEL_LOCAL_DYNAMIC:
-      tmp = gen_rtx_REG (Pmode, GP_RETURN);
-      dest = gen_reg_rtx (Pmode);
-      insn = loongarch_call_tls_get_addr (loc, SYMBOL_TLSLDM, tmp);
-      emit_libcall_block (insn, dest, tmp, loc);
-      break;
-
+      if (!TARGET_TLS_DESC)
+	{
+	  tmp = gen_rtx_REG (Pmode, GP_RETURN);
+	  dest = gen_reg_rtx (Pmode);
+	  insn = loongarch_call_tls_get_addr (loc, SYMBOL_TLSLDM, tmp);
+	  emit_libcall_block (insn, dest, tmp, loc);
+	  break;
+	}
+      /* Fall through.  */
     case TLS_MODEL_GLOBAL_DYNAMIC:
-      tmp = gen_rtx_REG (Pmode, GP_RETURN);
-      dest = gen_reg_rtx (Pmode);
-      insn = loongarch_call_tls_get_addr (loc, SYMBOL_TLSGD, tmp);
-      emit_libcall_block (insn, dest, tmp, loc);
+      if (TARGET_TLS_DESC)
+	{
+	  a0 = gen_rtx_REG (Pmode, GP_ARG_FIRST);
+	  dest = gen_reg_rtx (Pmode);
+	  tp = gen_rtx_REG (Pmode, THREAD_POINTER_REGNUM);
+
+	  if (TARGET_CMODEL_EXTREME)
+	    emit_insn (gen_got_load_tls_desc_off64 (loc, gen_reg_rtx (DImode)));
+	  else
+	    emit_insn (gen_got_load_tls_desc (Pmode, loc));
+
+	  emit_insn (gen_add3_insn (dest, a0, tp));
+	}
+      else
+	{
+	  tmp = gen_rtx_REG (Pmode, GP_RETURN);
+	  dest = gen_reg_rtx (Pmode);
+	  insn = loongarch_call_tls_get_addr (loc, SYMBOL_TLSGD, tmp);
+	  emit_libcall_block (insn, dest, tmp, loc);
+	}
       break;
 
     case TLS_MODEL_INITIAL_EXEC:
@@ -7654,6 +7673,7 @@ loongarch_option_override_internal (struct loongarch_target *target,
 			 opts->x_la_opt_abi_base,
 			 opts->x_la_opt_abi_ext,
 			 opts->x_la_opt_cmodel,
+			 opts->x_la_opt_tls_dialect,
 			 opts->x_la_isa_evolution,
 			 opts_set->x_la_isa_evolution);
 
@@ -7700,6 +7720,7 @@ loongarch_option_restore (struct gcc_options *,
   la_target.isa.evolution = ptr->x_la_isa_evolution;
 
   la_target.cmodel = ptr->x_la_opt_cmodel;
+  la_target.tls_dialect = ptr->x_la_opt_tls_dialect;
 }
 
 /* Implement TARGET_CONDITIONAL_REGISTER_USAGE.  */
diff --git a/gcc/config/loongarch/loongarch.md b/gcc/config/loongarch/loongarch.md
index 18fd9c1..a316c8f 100644
--- a/gcc/config/loongarch/loongarch.md
+++ b/gcc/config/loongarch/loongarch.md
@@ -52,6 +52,8 @@
 
   ;; TLS
   UNSPEC_TLS
+  UNSPEC_TLS_DESC
+  UNSPEC_TLS_DESC_OFF64
 
   ;; Stack tie
   UNSPEC_TIE
@@ -127,6 +129,15 @@
    (T1_REGNUM			13)
    (S0_REGNUM			23)
 
+   (FCC0_REGNUM			64)
+   (FCC1_REGNUM			65)
+   (FCC2_REGNUM			66)
+   (FCC3_REGNUM			67)
+   (FCC4_REGNUM			68)
+   (FCC5_REGNUM			69)
+   (FCC6_REGNUM			70)
+   (FCC7_REGNUM			71)
+
    ;; Return path styles
    (NORMAL_RETURN		0)
    (SIBCALL_RETURN		1)
@@ -2759,6 +2770,63 @@
 
 ;; Thread-Local Storage
 
+(define_insn "@got_load_tls_desc<mode>"
+  [(set (reg:P 4)
+	(unspec:P
+	    [(match_operand:P 0 "symbolic_operand" "")]
+	    UNSPEC_TLS_DESC))
+    (clobber (reg:SI FCC0_REGNUM))
+    (clobber (reg:SI FCC1_REGNUM))
+    (clobber (reg:SI FCC2_REGNUM))
+    (clobber (reg:SI FCC3_REGNUM))
+    (clobber (reg:SI FCC4_REGNUM))
+    (clobber (reg:SI FCC5_REGNUM))
+    (clobber (reg:SI FCC6_REGNUM))
+    (clobber (reg:SI FCC7_REGNUM))
+    (clobber (reg:SI RETURN_ADDR_REGNUM))]
+  "TARGET_TLS_DESC"
+{
+  return TARGET_EXPLICIT_RELOCS
+    ? "pcalau12i\t$r4,%%desc_pc_hi20(%0)\n\t"
+      "addi.d\t$r4,$r4,%%desc_pc_lo12(%0)\n\t"
+      "ld.d\t$r1,$r4,%%desc_ld(%0)\n\t"
+      "jirl\t$r1,$r1,%%desc_call(%0)"
+    : "la.tls.desc\t$r4,%0";
+}
+  [(set_attr "got" "load")
+   (set_attr "mode" "<MODE>")
+   (set_attr "length" "16")])
+
+(define_insn "got_load_tls_desc_off64"
+  [(set (reg:DI 4)
+	(unspec:DI
+	    [(match_operand:DI 0 "symbolic_operand" "")]
+	    UNSPEC_TLS_DESC_OFF64))
+    (clobber (reg:SI FCC0_REGNUM))
+    (clobber (reg:SI FCC1_REGNUM))
+    (clobber (reg:SI FCC2_REGNUM))
+    (clobber (reg:SI FCC3_REGNUM))
+    (clobber (reg:SI FCC4_REGNUM))
+    (clobber (reg:SI FCC5_REGNUM))
+    (clobber (reg:SI FCC6_REGNUM))
+    (clobber (reg:SI FCC7_REGNUM))
+    (clobber (reg:SI RETURN_ADDR_REGNUM))
+    (clobber (match_operand:DI 1 "register_operand" "=&r"))]
+  "TARGET_TLS_DESC && TARGET_CMODEL_EXTREME"
+{
+  return TARGET_EXPLICIT_RELOCS
+    ? "pcalau12i\t$r4,%%desc_pc_hi20(%0)\n\t"
+      "addi.d\t%1,$r0,%%desc_pc_lo12(%0)\n\t"
+      "lu32i.d\t%1,%%desc64_pc_lo20(%0)\n\t"
+      "lu52i.d\t%1,%1,%%desc64_pc_hi12(%0)\n\t"
+      "add.d\t$r4,$r4,%1\n\t"
+      "ld.d\t$r1,$r4,%%desc_ld(%0)\n\t"
+      "jirl\t$r1,$r1,%%desc_call(%0)"
+    : "la.tls.desc\t$r4,%1,%0";
+}
+  [(set_attr "got" "load")
+   (set_attr "length" "28")])
+
 (define_insn "@load_tls<mode>"
   [(set (match_operand:P 0 "register_operand" "=r")
 	(unspec:P
diff --git a/gcc/config/loongarch/loongarch.opt b/gcc/config/loongarch/loongarch.opt
index 317cd11..773747f 100644
--- a/gcc/config/loongarch/loongarch.opt
+++ b/gcc/config/loongarch/loongarch.opt
@@ -253,6 +253,20 @@ mpass-mrelax-to-as
 Driver Var(la_pass_mrelax_to_as) Init(HAVE_AS_MRELAX_OPTION)
 Pass -mrelax or -mno-relax option to the assembler.
 
+Enum
+Name(tls_type) Type(int)
+The possible TLS dialects:
+
+EnumValue
+Enum(tls_type) String(trad) Value(TLS_TRADITIONAL)
+
+EnumValue
+Enum(tls_type) String(desc) Value(TLS_DESCRIPTORS)
+
+mtls-dialect=
+Target RejectNegative Joined Enum(tls_type) Var(la_opt_tls_dialect) Init(M_OPT_UNSET) Save
+Specify TLS dialect.
+
 -param=loongarch-vect-unroll-limit=
 Target Joined UInteger Var(la_vect_unroll_limit) Init(6) IntegerRange(1, 64) Param
 Used to limit unroll factor which indicates how much the autovectorizer may
diff --git a/gcc/config/loongarch/loongarch.opt.urls b/gcc/config/loongarch/loongarch.opt.urls
index 8e16304..88f0bb0 100644
--- a/gcc/config/loongarch/loongarch.opt.urls
+++ b/gcc/config/loongarch/loongarch.opt.urls
@@ -64,6 +64,9 @@ UrlSuffix(gcc/LoongArch-Options.html#index-mdirect-extern-access)
 
 ; skipping UrlSuffix for 'mrelax' due to finding no URLs
 
+mtls-dialect=
+UrlSuffix(gcc/LoongArch-Options.html#index-mtls-dialect-1)
+
 mfrecipe
 UrlSuffix(gcc/LoongArch-Options.html#index-mfrecipe)