From 2a1c53684ccbcc2b71c98f2cf7943670f54d380b Mon Sep 17 00:00:00 2001 From: Tatsuyuki Ishi Date: Thu, 17 Aug 2023 17:44:25 +0900 Subject: [PATCH] RISC-V: Implement TLS Descriptors. This implements TLS Descriptors (TLSDESC) as specified in [1]. The 4-instruction sequence is implemented as a single RTX insn for simplicity, but this can be revisited later if instruction scheduling or more flexible RA is desired. The default remains to be the traditional TLS model, but can be configured with --with_tls={trad,desc}. The choice can be revisited once toolchain and libc support ships. [1]: https://github.com/riscv-non-isa/riscv-elf-psabi-doc/pull/373. gcc/Changelog: * config/riscv/riscv.opt: Add -mtls-dialect to configure TLS flavor. * config.gcc: Add --with_tls configuration option to change the default TLS flavor. * config/riscv/riscv.h: Add TARGET_TLSDESC determined from -mtls-dialect and with_tls defaults. * config/riscv/riscv-opts.h: Define enum riscv_tls_type for the two TLS flavors. * config/riscv/riscv-protos.h: Define SYMBOL_TLSDESC symbol type. * config/riscv/riscv.md: Add instruction sequence for TLSDESC. * config/riscv/riscv.cc (riscv_symbol_insns): Add instruction sequence length data for TLSDESC. (riscv_legitimize_tls_address): Add lowering of TLSDESC. * doc/install.texi: Document --with-tls for RISC-V. * doc/invoke.texi: Document -mtls-dialect for RISC-V. --- gcc/config.gcc | 15 ++++++++++++++- gcc/config/riscv/riscv-opts.h | 6 ++++++ gcc/config/riscv/riscv-protos.h | 5 +++-- gcc/config/riscv/riscv.cc | 24 ++++++++++++++++++++---- gcc/config/riscv/riscv.h | 9 +++++++-- gcc/config/riscv/riscv.md | 20 +++++++++++++++++++- gcc/config/riscv/riscv.opt | 14 ++++++++++++++ gcc/doc/install.texi | 3 +++ gcc/doc/invoke.texi | 13 ++++++++++++- 9 files changed, 98 insertions(+), 11 deletions(-) diff --git a/gcc/config.gcc b/gcc/config.gcc index 17873ac210390..1a5870672d2ac 100644 --- a/gcc/config.gcc +++ b/gcc/config.gcc @@ -2492,6 +2492,7 @@ riscv*-*-linux*) # Force .init_array support. The configure script cannot always # automatically detect that GAS supports it, yet we require it. gcc_cv_initfini_array=yes + with_tls=${with_tls:-trad} ;; riscv*-*-elf* | riscv*-*-rtems*) tm_file="elfos.h newlib-stdint.h ${tm_file} riscv/elf.h" @@ -2534,6 +2535,7 @@ riscv*-*-freebsd*) # Force .init_array support. The configure script cannot always # automatically detect that GAS supports it, yet we require it. gcc_cv_initfini_array=yes + with_tls=${with_tls:-trad} ;; loongarch*-*-linux*) @@ -4671,7 +4673,7 @@ case "${target}" in ;; riscv*-*-*) - supported_defaults="abi arch tune riscv_attribute isa_spec" + supported_defaults="abi arch tune riscv_attribute isa_spec tls" case "${target}" in riscv-* | riscv32*) xlen=32 ;; @@ -4801,6 +4803,17 @@ case "${target}" in ;; esac fi + # Handle --with-tls. + case "$with_tls" in + "" \ + | trad | desc) + # OK + ;; + *) + echo "Unknown TLS method used in --with-tls=$with_tls" 1>&2 + exit 1 + ;; + esac # Handle --with-multilib-list. if test "x${with_multilib_list}" != xdefault; then diff --git a/gcc/config/riscv/riscv-opts.h b/gcc/config/riscv/riscv-opts.h index 392b9169240df..1b2dd5757a8e1 100644 --- a/gcc/config/riscv/riscv-opts.h +++ b/gcc/config/riscv/riscv-opts.h @@ -154,4 +154,10 @@ enum rvv_vector_bits_enum { #define TARGET_MAX_LMUL \ (int) (rvv_max_lmul == RVV_DYNAMIC ? RVV_M8 : rvv_max_lmul) +/* TLS types. */ +enum riscv_tls_type { + TLS_TRADITIONAL, + TLS_DESCRIPTORS +}; + #endif /* ! GCC_RISCV_OPTS_H */ diff --git a/gcc/config/riscv/riscv-protos.h b/gcc/config/riscv/riscv-protos.h index b87355938052a..066a5a5a7cccd 100644 --- a/gcc/config/riscv/riscv-protos.h +++ b/gcc/config/riscv/riscv-protos.h @@ -34,9 +34,10 @@ enum riscv_symbol_type { SYMBOL_TLS, SYMBOL_TLS_LE, SYMBOL_TLS_IE, - SYMBOL_TLS_GD + SYMBOL_TLS_GD, + SYMBOL_TLSDESC, }; -#define NUM_SYMBOL_TYPES (SYMBOL_TLS_GD + 1) +#define NUM_SYMBOL_TYPES (SYMBOL_TLSDESC + 1) /* Classifies an address. diff --git a/gcc/config/riscv/riscv.cc b/gcc/config/riscv/riscv.cc index fe9976bfffe98..deac3e4e9e37e 100644 --- a/gcc/config/riscv/riscv.cc +++ b/gcc/config/riscv/riscv.cc @@ -1072,6 +1072,7 @@ static int riscv_symbol_insns (enum riscv_symbol_type type) case SYMBOL_ABSOLUTE: return 2; /* LUI + the reference. */ case SYMBOL_PCREL: return 2; /* AUIPC + the reference. */ case SYMBOL_TLS_LE: return 3; /* LUI + ADD TP + the reference. */ + case SYMBOL_TLSDESC: return 6; /* 4-instruction call + ADD TP + the reference. */ case SYMBOL_GOT_DISP: return 3; /* AUIPC + LD GOT + the reference. */ case SYMBOL_FORCE_TO_MEM: return 3; /* AUIPC + LD + the reference. */ default: gcc_unreachable (); @@ -2220,7 +2221,7 @@ riscv_call_tls_get_addr (rtx sym, rtx result) static rtx riscv_legitimize_tls_address (rtx loc) { - rtx dest, tp, tmp; + rtx dest, tp, tmp, a0; enum tls_model model = SYMBOL_REF_TLS_MODEL (loc); #if 0 @@ -2236,9 +2237,24 @@ riscv_legitimize_tls_address (rtx loc) /* Rely on section anchors for the optimization that LDM TLS provides. The anchor's address is loaded with GD TLS. */ case TLS_MODEL_GLOBAL_DYNAMIC: - tmp = gen_rtx_REG (Pmode, GP_RETURN); - dest = gen_reg_rtx (Pmode); - emit_libcall_block (riscv_call_tls_get_addr (loc, tmp), dest, tmp, loc); + if (TARGET_TLSDESC) + { + static unsigned seqno; + tp = gen_rtx_REG (Pmode, THREAD_POINTER_REGNUM); + a0 = gen_rtx_REG (Pmode, GP_ARG_FIRST); + dest = gen_reg_rtx (Pmode); + + emit_insn (gen_tlsdesc (Pmode, loc, GEN_INT (seqno))); + emit_insn (gen_add3_insn (dest, a0, tp)); + seqno++; + } + else + { + tmp = gen_rtx_REG (Pmode, GP_RETURN); + dest = gen_reg_rtx (Pmode); + emit_libcall_block (riscv_call_tls_get_addr (loc, tmp), dest, tmp, + loc); + } break; case TLS_MODEL_INITIAL_EXEC: diff --git a/gcc/config/riscv/riscv.h b/gcc/config/riscv/riscv.h index da089a03e9d1f..10ad4aedd70f8 100644 --- a/gcc/config/riscv/riscv.h +++ b/gcc/config/riscv/riscv.h @@ -64,6 +64,7 @@ extern const char *riscv_arch_help (int argc, const char **argv); --with-abi is ignored if -mabi is specified. --with-tune is ignored if -mtune or -mcpu is specified. --with-isa-spec is ignored if -misa-spec is specified. + --with-tls is ignored if -mtls-dialect is specified. But using default -march/-mtune value if -mcpu don't have valid option. */ #define OPTION_DEFAULT_SPECS \ @@ -73,8 +74,9 @@ extern const char *riscv_arch_help (int argc, const char **argv); {"arch", "%{!march=*:" \ " %{!mcpu=*:-march=%(VALUE)}" \ " %{mcpu=*:%:riscv_expand_arch_from_cpu(%* %(VALUE))}}" }, \ - {"abi", "%{!mabi=*:-mabi=%(VALUE)}" }, \ - {"isa_spec", "%{!misa-spec=*:-misa-spec=%(VALUE)}" }, \ + {"abi", "%{!mabi=*:-mabi=%(VALUE)}" }, \ + {"isa_spec", "%{!misa-spec=*:-misa-spec=%(VALUE)}" }, \ + {"tls", "%{!mtls-dialect=*:-mtls-dialect=%(VALUE)}"}, \ #ifdef IN_LIBGCC2 #undef TARGET_64BIT @@ -1228,4 +1230,7 @@ extern void riscv_remove_unneeded_save_restore_calls (void); #define HAVE_POST_MODIFY_DISP TARGET_XTHEADMEMIDX #define HAVE_PRE_MODIFY_DISP TARGET_XTHEADMEMIDX +/* Check TLS Descriptors mechanism is selected. */ +#define TARGET_TLSDESC (riscv_tls_dialect == TLS_DESCRIPTORS) + #endif /* ! GCC_RISCV_H */ diff --git a/gcc/config/riscv/riscv.md b/gcc/config/riscv/riscv.md index 0346cc3859d8e..c2b4323c53a78 100644 --- a/gcc/config/riscv/riscv.md +++ b/gcc/config/riscv/riscv.md @@ -48,7 +48,7 @@ UNSPEC_TLS_LE UNSPEC_TLS_IE UNSPEC_TLS_GD - + UNSPEC_TLSDESC ;; High part of PC-relative address. UNSPEC_AUIPC @@ -2089,6 +2089,24 @@ (set_attr "type" "load") (set_attr "mode" "")]) +(define_insn "@tlsdesc" + [(set (reg:P A0_REGNUM) + (unspec:P + [(match_operand:P 0 "symbolic_operand" "") + (match_operand:P 1 "const_int_operand")] + UNSPEC_TLSDESC)) + (clobber (reg:P T0_REGNUM))] + "TARGET_TLSDESC" + { + return ".LT%1: auipc\ta0,%%tlsdesc_hi(%0)\;" + "\tt0,%%tlsdesc_load_lo(.LT%1)(a0)\;" + "addi\ta0,a0,%%tlsdesc_add_lo(.LT%1)\;" + "jalr\tt0,t0,%%tlsdesc_call(.LT%1)"; + } + [(set_attr "type" "multi") + (set_attr "length" "16") + (set_attr "mode" "")]) + (define_insn "auipc" [(set (match_operand:P 0 "register_operand" "=r") (unspec:P diff --git a/gcc/config/riscv/riscv.opt b/gcc/config/riscv/riscv.opt index 7d625af02d52f..8da0764eb4bec 100644 --- a/gcc/config/riscv/riscv.opt +++ b/gcc/config/riscv/riscv.opt @@ -606,3 +606,17 @@ Enum(rvv_vector_bits) String(zvl) Value(RVV_VECTOR_BITS_ZVL) mrvv-vector-bits= Target RejectNegative Joined Enum(rvv_vector_bits) Var(rvv_vector_bits) Init(RVV_VECTOR_BITS_SCALABLE) -mrvv-vector-bits= Set the kind of bits for an RVV vector register. + +Enum +Name(tls_type) Type(enum riscv_tls_type) +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(riscv_tls_dialect) Init(TLS_TRADITIONAL) Save +Specify TLS dialect. diff --git a/gcc/doc/install.texi b/gcc/doc/install.texi index 269fe7ec87012..120bb045f4d61 100644 --- a/gcc/doc/install.texi +++ b/gcc/doc/install.texi @@ -1187,6 +1187,9 @@ Specify the default TLS dialect, for systems were there is a choice. For ARM targets, possible values for @var{dialect} are @code{gnu} or @code{gnu2}, which select between the original GNU dialect and the GNU TLS descriptor-based dialect. +For RISC-V targets, possible values for @var{dialect} are @code{trad} or +@code{desc}, which select between the traditional GNU dialect and the GNU TLS +descriptor-based dialect. @item --enable-multiarch Specify whether to enable or disable multiarch support. The default is diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi index d09074e13de46..e4112bbe61e07 100644 --- a/gcc/doc/invoke.texi +++ b/gcc/doc/invoke.texi @@ -1262,7 +1262,8 @@ See RS/6000 and PowerPC Options. -minline-atomics -mno-inline-atomics -minline-strlen -mno-inline-strlen -minline-strcmp -mno-inline-strcmp --minline-strncmp -mno-inline-strncmp} +-minline-strncmp -mno-inline-strncmp +-mtls-dialect=desc -mtls-dialect=trad} @emph{RL78 Options} @gccoptlist{-msim -mmul=none -mmul=g13 -mmul=g14 -mallregs @@ -30975,6 +30976,16 @@ which register to use as base register for reading the canary, and from what offset from that base register. There is no default register or offset as this is entirely for use within the Linux kernel. + +@opindex mtls-dialect=desc +@item -mtls-dialect=desc +Use TLS descriptors as the thread-local storage mechanism for dynamic accesses +of TLS variables. + +@opindex mtls-dialect=trad +@item -mtls-dialect=trad +Use traditional TLS as the thread-local storage mechanism for dynamic accesses +of TLS variables. This is the default. @end table @node RL78 Options