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Diffstat (limited to 'gcc/config/bpf/bpf.c')
| -rw-r--r-- | gcc/config/bpf/bpf.c | 948 |
1 files changed, 948 insertions, 0 deletions
diff --git a/gcc/config/bpf/bpf.c b/gcc/config/bpf/bpf.c new file mode 100644 index 0000000..8b2a592 --- /dev/null +++ b/gcc/config/bpf/bpf.c @@ -0,0 +1,948 @@ +/* Subroutines used for code generation for eBPF. + Copyright (C) 2019 Free Software Foundation, Inc. + +This file is part of GCC. + +GCC is free software; you can redistribute it and/or modify +it under the terms of the GNU General Public License as published by +the Free Software Foundation; either version 3, or (at your option) +any later version. + +GCC is distributed in the hope that it will be useful, +but WITHOUT ANY WARRANTY; without even the implied warranty of +MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +GNU General Public License for more details. + +You should have received a copy of the GNU General Public License +along with GCC; see the file COPYING3. If not see +<http://www.gnu.org/licenses/>. */ + +#define IN_TARGET_CODE 1 + +#include "config.h" +#include "system.h" +#include "coretypes.h" +#include "tm.h" +#include "rtl.h" +#include "regs.h" +#include "insn-config.h" +#include "insn-attr.h" +#include "recog.h" +#include "output.h" +#include "alias.h" +#include "tree.h" +#include "stringpool.h" +#include "attribs.h" +#include "varasm.h" +#include "stor-layout.h" +#include "calls.h" +#include "function.h" +#include "explow.h" +#include "memmodel.h" +#include "emit-rtl.h" +#include "reload.h" +#include "tm_p.h" +#include "target.h" +#include "target-def.h" +#include "basic-block.h" +#include "expr.h" +#include "optabs.h" +#include "bitmap.h" +#include "df.h" +#include "c-family/c-common.h" +#include "diagnostic.h" +#include "builtins.h" +#include "predict.h" +#include "langhooks.h" + +/* Per-function machine data. */ +struct GTY(()) machine_function +{ + /* Number of bytes saved on the stack for local variables. */ + int local_vars_size; + + /* Number of bytes saved on the stack for callee-saved + registers. */ + int callee_saved_reg_size; +}; + +/* Data structures for the eBPF specific built-ins. */ + +/* Maximum number of arguments taken by a builtin function, plus + one. */ +#define BPF_BUILTIN_MAX_ARGS 5 + +enum bpf_builtins +{ + BPF_BUILTIN_UNUSED = 0, + /* Built-ins for kernel helpers. */ +#define DEF_HELPER(V,D,N,T) BPF_BUILTIN_HELPER_##D, +# include "bpf-helpers.def" +#undef DEF_HELPER + BPF_BUILTIN_HELPER_MAX, + /* Built-ins for non-generic loads and stores. */ + BPF_BUILTIN_LOAD_BYTE = BPF_BUILTIN_HELPER_MAX, + BPF_BUILTIN_LOAD_HALF, + BPF_BUILTIN_LOAD_WORD, + BPF_BUILTIN_MAX, +}; + +/* This table is indexed by an enum bpf_builtin. */ +static const char *bpf_helper_names[] = +{ + NULL, +#define DEF_HELPER(V,D,N,T) #N, +# include "bpf-helpers.def" +#undef DEF_HELPER + NULL, + NULL, + NULL, + NULL +}; + +/* Return the builtin code corresponding to the kernel helper builtin + __builtin_NAME, or 0 if the name doesn't correspond to a kernel + helper builtin. */ + +static inline int +bpf_helper_code (const char *name) +{ + int i; + + for (i = 1; i < BPF_BUILTIN_HELPER_MAX; ++i) + if (strcmp (name, bpf_helper_names[i]) == 0) + return i; + + return 0; +} + +static GTY (()) tree bpf_builtins[(int) BPF_BUILTIN_MAX]; + +/* Initialize the per-function machine status. */ + +static struct machine_function * +bpf_init_machine_status (void) +{ + /* Note this initializes all fields to 0, which is just OK for + us. */ + return ggc_cleared_alloc<machine_function> (); +} + +/* Override options and do some other initialization. */ + +static void +bpf_option_override (void) +{ + /* Set the initializer for the per-function status structure. */ + init_machine_status = bpf_init_machine_status; +} + +#undef TARGET_OPTION_OVERRIDE +#define TARGET_OPTION_OVERRIDE bpf_option_override + +/* Define target-specific CPP macros. This function in used in the + definition of TARGET_CPU_CPP_BUILTINS in bpf.h */ + +#define builtin_define(TXT) cpp_define (pfile, TXT) + +void +bpf_target_macros (cpp_reader *pfile) +{ + builtin_define ("__BPF__"); + + if (TARGET_BIG_ENDIAN) + builtin_define ("__BPF_BIG_ENDIAN__"); + else + builtin_define ("__BPF_LITTLE_ENDIAN__"); + + /* Define BPF_KERNEL_VERSION_CODE */ + { + const char *version_code; + char *kernel_version_code; + + switch (bpf_kernel) + { + case LINUX_V4_0: version_code = "0x40000"; break; + case LINUX_V4_1: version_code = "0x40100"; break; + case LINUX_V4_2: version_code = "0x40200"; break; + case LINUX_V4_3: version_code = "0x40300"; break; + case LINUX_V4_4: version_code = "0x40400"; break; + case LINUX_V4_5: version_code = "0x40500"; break; + case LINUX_V4_6: version_code = "0x40600"; break; + case LINUX_V4_7: version_code = "0x40700"; break; + case LINUX_V4_8: version_code = "0x40800"; break; + case LINUX_V4_9: version_code = "0x40900"; break; + case LINUX_V4_10: version_code = "0x40a00"; break; + case LINUX_V4_11: version_code = "0x40b00"; break; + case LINUX_V4_12: version_code = "0x40c00"; break; + case LINUX_V4_13: version_code = "0x40d00"; break; + case LINUX_V4_14: version_code = "0x40e00"; break; + case LINUX_V4_15: version_code = "0x40f00"; break; + case LINUX_V4_16: version_code = "0x41000"; break; + case LINUX_V4_17: version_code = "0x42000"; break; + case LINUX_V4_18: version_code = "0x43000"; break; + case LINUX_V4_19: version_code = "0x44000"; break; + case LINUX_V4_20: version_code = "0x45000"; break; + case LINUX_V5_0: version_code = "0x50000"; break; + case LINUX_V5_1: version_code = "0x50100"; break; + case LINUX_V5_2: version_code = "0x50200"; break; + default: + gcc_unreachable (); + } + + kernel_version_code = ACONCAT (("__BPF_KERNEL_VERSION_CODE__=", + version_code, NULL)); + builtin_define (kernel_version_code); + } +} + +/* Output assembly directives to switch to section NAME. The section + should have attributes as specified by FLAGS, which is a bit mask + of the 'SECTION_*' flags defined in 'output.h'. If DECL is + non-NULL, it is the 'VAR_DECL' or 'FUNCTION_DECL' with which this + section is associated. */ + +static void +bpf_asm_named_section (const char *name, + unsigned int flags ATTRIBUTE_UNUSED, + tree decl ATTRIBUTE_UNUSED) +{ + fprintf (asm_out_file, "\t.section\t%s\n", name); +} + +#undef TARGET_ASM_NAMED_SECTION +#define TARGET_ASM_NAMED_SECTION bpf_asm_named_section + +/* Return an RTX representing the place where a function returns or + receives a value of data type RET_TYPE, a tree node representing a + data type. */ + +static rtx +bpf_function_value (const_tree ret_type, + const_tree fntype_or_decl, + bool outgoing ATTRIBUTE_UNUSED) +{ + enum machine_mode mode; + int unsignedp; + + mode = TYPE_MODE (ret_type); + if (INTEGRAL_TYPE_P (ret_type)) + mode = promote_function_mode (ret_type, mode, &unsignedp, + fntype_or_decl, 1); + + return gen_rtx_REG (mode, BPF_R0); +} + +#undef TARGET_FUNCTION_VALUE +#define TARGET_FUNCTION_VALUE bpf_function_value + +/* Return true if REGNO is the number of a hard register in which the + values of called function may come back. */ + +static bool +bpf_function_value_regno_p (const unsigned int regno) +{ + return (regno == BPF_R0); +} + +#undef TARGET_FUNCTION_VALUE_REGNO_P +#define TARGET_FUNCTION_VALUE_REGNO_P bpf_function_value_regno_p + +/* Compute the size of the function's stack frame, including the local + area and the register-save area. */ + +static void +bpf_compute_frame_layout (void) +{ + int stack_alignment = STACK_BOUNDARY / BITS_PER_UNIT; + int padding_locals, regno; + + /* Set the space used in the stack by local variables. This is + rounded up to respect the minimum stack alignment. */ + cfun->machine->local_vars_size = get_frame_size (); + + padding_locals = cfun->machine->local_vars_size % stack_alignment; + if (padding_locals) + padding_locals = stack_alignment - padding_locals; + + cfun->machine->local_vars_size += padding_locals; + + /* Set the space used in the stack by callee-saved used registers in + the current function. There is no need to round up, since the + registers are all 8 bytes wide. */ + for (regno = 0; regno < FIRST_PSEUDO_REGISTER; regno++) + if ((!fixed_regs[regno] + && df_regs_ever_live_p (regno) + && !call_used_regs[regno]) + || (cfun->calls_alloca + && regno == STACK_POINTER_REGNUM)) + cfun->machine->callee_saved_reg_size += 8; + + /* Check that the total size of the frame doesn't exceed the limit + imposed by eBPF. */ + if ((cfun->machine->local_vars_size + + cfun->machine->callee_saved_reg_size) > bpf_frame_limit) + { + static int stack_limit_exceeded = 0; + + if (!stack_limit_exceeded) + error ("eBPF stack limit exceeded"); + stack_limit_exceeded = 1; + } +} + +#undef TARGET_COMPUTE_FRAME_LAYOUT +#define TARGET_COMPUTE_FRAME_LAYOUT bpf_compute_frame_layout + +/* Expand to the instructions in a function prologue. This function + is called when expanding the 'prologue' pattern in bpf.md. */ + +void +bpf_expand_prologue (void) +{ + int regno, fp_offset; + rtx insn; + HOST_WIDE_INT size; + + size = (cfun->machine->local_vars_size + + cfun->machine->callee_saved_reg_size); + fp_offset = -cfun->machine->local_vars_size; + + /* Save callee-saved hard registes. The register-save-area starts + right after the local variables. */ + for (regno = 0; regno < FIRST_PSEUDO_REGISTER; regno++) + { + if ((!fixed_regs[regno] + && df_regs_ever_live_p (regno) + && !call_used_regs[regno]) + || (cfun->calls_alloca + && regno == STACK_POINTER_REGNUM)) + { + rtx mem; + + if (!IN_RANGE (fp_offset, -1 - 0x7fff, 0x7fff)) + /* This has been already reported as an error in + bpf_compute_frame_layout. */ + break; + else + { + mem = gen_frame_mem (DImode, + plus_constant (DImode, + hard_frame_pointer_rtx, + fp_offset - 8)); + insn = emit_move_insn (mem, gen_rtx_REG (DImode, regno)); + RTX_FRAME_RELATED_P (insn) = 1; + fp_offset -= 8; + } + } + } + + /* Set the stack pointer, if the function allocates space + dynamically. Note that the value of %sp should be directly + derived from %fp, for the kernel verifier to track it as a stack + accessor. */ + if (cfun->calls_alloca) + { + insn = emit_move_insn (stack_pointer_rtx, + hard_frame_pointer_rtx); + RTX_FRAME_RELATED_P (insn) = 1; + + if (size > 0) + { + insn = emit_insn (gen_rtx_SET (stack_pointer_rtx, + gen_rtx_PLUS (Pmode, + stack_pointer_rtx, + GEN_INT (-size)))); + RTX_FRAME_RELATED_P (insn) = 1; + } + } +} + +/* Expand to the instructions in a function epilogue. This function + is called when expanding the 'epilogue' pattern in bpf.md. */ + +void +bpf_expand_epilogue (void) +{ + int regno, fp_offset; + rtx insn; + + fp_offset = -cfun->machine->local_vars_size; + + /* Restore callee-saved hard registes from the stack. */ + for (regno = 0; regno < FIRST_PSEUDO_REGISTER; regno++) + { + if ((!fixed_regs[regno] + && df_regs_ever_live_p (regno) + && !call_used_regs[regno]) + || (cfun->calls_alloca + && regno == STACK_POINTER_REGNUM)) + { + rtx mem; + + if (!IN_RANGE (fp_offset, -1 - 0x7fff, 0x7fff)) + /* This has been already reported as an error in + bpf_compute_frame_layout. */ + break; + else + { + mem = gen_frame_mem (DImode, + plus_constant (DImode, + hard_frame_pointer_rtx, + fp_offset - 8)); + insn = emit_move_insn (gen_rtx_REG (DImode, regno), mem); + RTX_FRAME_RELATED_P (insn) = 1; + fp_offset -= 8; + } + } + } + + emit_jump_insn (gen_exit ()); +} + +/* Return the initial difference between the specified pair of + registers. The registers that can figure in FROM, and TO, are + specified by ELIMINABLE_REGS in bpf.h. + + This function is used in the definition of + INITIAL_ELIMINATION_OFFSET in bpf.h */ + +HOST_WIDE_INT +bpf_initial_elimination_offset (int from, int to) +{ + HOST_WIDE_INT ret; + + if (from == ARG_POINTER_REGNUM && to == STACK_POINTER_REGNUM) + ret = (cfun->machine->local_vars_size + + cfun->machine->callee_saved_reg_size); + else if (from == ARG_POINTER_REGNUM && to == FRAME_POINTER_REGNUM) + ret = 0; + else + gcc_unreachable (); + + return ret; +} + +/* Return the number of consecutive hard registers, starting at + register number REGNO, required to hold a value of mode MODE. */ + +static unsigned int +bpf_hard_regno_nregs (unsigned int regno ATTRIBUTE_UNUSED, + enum machine_mode mode) +{ + return CEIL (GET_MODE_SIZE (mode), UNITS_PER_WORD); +} + +#undef TARGET_HARD_REGNO_NREGS +#define TARGET_HARD_REGNO_NREGS bpf_hard_regno_nregs + +/* Return true if it is permissible to store a value of mode MODE in + hard register number REGNO, or in several registers starting with + that one. */ + +static bool +bpf_hard_regno_mode_ok (unsigned int regno ATTRIBUTE_UNUSED, + enum machine_mode mode) +{ + switch (mode) + { + case E_SImode: + case E_DImode: + case E_HImode: + case E_QImode: + case E_TImode: + case E_SFmode: + case E_DFmode: + return true; + default: + return false; + } +} + +#undef TARGET_HARD_REGNO_MODE_OK +#define TARGET_HARD_REGNO_MODE_OK bpf_hard_regno_mode_ok + +/* Return true if a function must have and use a frame pointer. */ + +static bool +bpf_frame_pointer_required (void) +{ + /* We do not have a stack pointer, so we absolutely depend on the + frame-pointer in order to access the stack... and fishes walk and + pigs fly glglgl */ + return true; +} + +#undef TARGET_FRAME_POINTER_REQUIRED +#define TARGET_FRAME_POINTER_REQUIRED bpf_frame_pointer_required + +/* Return `true' if the given RTX X is a valid base for an indirect + memory access. STRICT has the same meaning than in + bpf_legitimate_address_p. */ + +static inline bool +bpf_address_base_p (rtx x, bool strict) +{ + return (GET_CODE (x) == REG + && (REGNO (x) < 11 + || (!strict && REGNO (x) >= FIRST_PSEUDO_REGISTER))); +} + +/* Return true if X (a RTX) is a legitimate memory address on the + target machine for a memory operand of mode MODE. */ + +static bool +bpf_legitimate_address_p (machine_mode mode ATTRIBUTE_UNUSED, + rtx x, + bool strict) +{ + switch (GET_CODE (x)) + { + case REG: + return bpf_address_base_p (x, strict); + + case PLUS: + { + /* Accept (PLUS ADDR_BASE CONST_INT), provided CONST_INT fits + in a signed 16-bit. + + Note that LABEL_REF and SYMBOL_REF are not allowed in + REG+IMM addresses, because it is almost certain they will + overload the offset field. */ + + rtx x0 = XEXP (x, 0); + rtx x1 = XEXP (x, 1); + + if (bpf_address_base_p (x0, strict) && GET_CODE (x1) == CONST_INT) + return IN_RANGE (INTVAL (x1), -1 - 0x7fff, 0x7fff); + + break; + } + default: + break; + } + + return false; +} + +#undef TARGET_LEGITIMATE_ADDRESS_P +#define TARGET_LEGITIMATE_ADDRESS_P bpf_legitimate_address_p + +/* Describe the relative costs of RTL expressions. Return true when + all subexpressions of X have been processed, and false when + `rtx_cost' should recurse. */ + +static bool +bpf_rtx_costs (rtx x ATTRIBUTE_UNUSED, + enum machine_mode mode ATTRIBUTE_UNUSED, + int outer_code ATTRIBUTE_UNUSED, + int opno ATTRIBUTE_UNUSED, + int *total ATTRIBUTE_UNUSED, + bool speed ATTRIBUTE_UNUSED) +{ + /* To be written. */ + return false; +} + +#undef TARGET_RTX_COSTS +#define TARGET_RTX_COSTS bpf_rtx_costs + +/* Return true if an argument at the position indicated by CUM should + be passed by reference. If the hook returns true, a copy of that + argument is made in memory and a pointer to the argument is passed + instead of the argument itself. */ + +static bool +bpf_pass_by_reference (cumulative_args_t cum ATTRIBUTE_UNUSED, + const function_arg_info &arg) +{ + unsigned num_bytes = arg.type_size_in_bytes (); + + /* Pass aggregates and values bigger than 5 words by reference. + Everything else is passed by copy. */ + return (arg.aggregate_type_p () || (num_bytes > 8*5)); +} + +#undef TARGET_PASS_BY_REFERENCE +#define TARGET_PASS_BY_REFERENCE bpf_pass_by_reference + +/* Return a RTX indicating whether a function argument is passed in a + register and if so, which register. */ + +static rtx +bpf_function_arg (cumulative_args_t ca, const function_arg_info &arg) +{ + CUMULATIVE_ARGS *cum = get_cumulative_args (ca); + + if (*cum < 5) + return gen_rtx_REG (arg.mode, *cum + 1); + else + /* An error will be emitted for this in + bpf_function_arg_advance. */ + return NULL_RTX; +} + +#undef TARGET_FUNCTION_ARG +#define TARGET_FUNCTION_ARG bpf_function_arg + +/* Update the summarizer variable pointed by CA to advance past an + argument in the argument list. */ + +static void +bpf_function_arg_advance (cumulative_args_t ca, + const function_arg_info &arg) +{ + CUMULATIVE_ARGS *cum = get_cumulative_args (ca); + unsigned num_bytes = arg.type_size_in_bytes (); + unsigned num_words = CEIL (num_bytes, UNITS_PER_WORD); + + if (*cum <= 5 && *cum + num_words > 5) + error ("too many function arguments for eBPF"); + + *cum += num_words; +} + +#undef TARGET_FUNCTION_ARG_ADVANCE +#define TARGET_FUNCTION_ARG_ADVANCE bpf_function_arg_advance + +/* Output the assembly code for a constructor. Since eBPF doesn't + support indirect calls, constructors are not supported. */ + +static void +bpf_output_constructor (rtx symbol, int priority ATTRIBUTE_UNUSED) +{ + tree decl = SYMBOL_REF_DECL (symbol); + + if (decl) + sorry_at (DECL_SOURCE_LOCATION (decl), + "no constructors"); + else + sorry ("no constructors"); +} + +#undef TARGET_ASM_CONSTRUCTOR +#define TARGET_ASM_CONSTRUCTOR bpf_output_constructor + +/* Output the assembly code for a destructor. Since eBPF doesn't + support indirect calls, destructors are not supported. */ + +static void +bpf_output_destructor (rtx symbol, int priority ATTRIBUTE_UNUSED) +{ + tree decl = SYMBOL_REF_DECL (symbol); + + if (decl) + sorry_at (DECL_SOURCE_LOCATION (decl), + "no destructors"); + else + sorry ("no destructors"); +} + +#undef TARGET_ASM_DESTRUCTOR +#define TARGET_ASM_DESTRUCTOR bpf_output_destructor + +/* Return the appropriate instruction to CALL to a function. TARGET + is an RTX denoting the address of the called function. + + The main purposes of this function are: + - To reject indirect CALL instructions, which are not supported by + eBPF. + - To recognize calls to kernel helper functions and emit the + corresponding CALL N instruction. + + This function is called from the expansion of the 'call' pattern in + bpf.md. */ + +const char * +bpf_output_call (rtx target) +{ + rtx xops[1]; + + switch (GET_CODE (target)) + { + case CONST_INT: + output_asm_insn ("call\t%0", &target); + break; + case SYMBOL_REF: + { + const char *function_name = XSTR (target, 0); + int code; + + if (strncmp (function_name, "__builtin_bpf_helper_", 21) == 0 + && ((code = bpf_helper_code (function_name + 21)) != 0)) + { + xops[0] = GEN_INT (code); + output_asm_insn ("call\t%0", xops); + } + else + output_asm_insn ("call\t%0", &target); + + break; + } + default: + error ("indirect call in function, which are not supported by eBPF"); + output_asm_insn ("call 0", NULL); + break; + } + + return ""; +} + +/* Print an instruction operand. This function is called in the macro + PRINT_OPERAND defined in bpf.h */ + +void +bpf_print_operand (FILE *file, rtx op, int code ATTRIBUTE_UNUSED) +{ + switch (GET_CODE (op)) + { + case REG: + fprintf (file, "%s", reg_names[REGNO (op)]); + break; + case MEM: + output_address (GET_MODE (op), XEXP (op, 0)); + break; + case CONST_DOUBLE: + if (CONST_DOUBLE_HIGH (op)) + fprintf (file, HOST_WIDE_INT_PRINT_DOUBLE_HEX, + CONST_DOUBLE_HIGH (op), CONST_DOUBLE_LOW (op)); + else if (CONST_DOUBLE_LOW (op) < 0) + fprintf (file, HOST_WIDE_INT_PRINT_HEX, CONST_DOUBLE_LOW (op)); + else + fprintf (file, HOST_WIDE_INT_PRINT_DEC, CONST_DOUBLE_LOW (op)); + break; + default: + output_addr_const (file, op); + } +} + +/* Print an operand which is an address. This function should handle + any legit address, as accepted by bpf_legitimate_address_p, and + also addresses that are valid in CALL instructions. + + This function is called in the PRINT_OPERAND_ADDRESS macro defined + in bpf.h */ + +void +bpf_print_operand_address (FILE *file, rtx addr) +{ + switch (GET_CODE (addr)) + { + case REG: + fprintf (file, "[%s+0]", reg_names[REGNO (addr)]); + break; + case PLUS: + { + rtx op0 = XEXP (addr, 0); + rtx op1 = XEXP (addr, 1); + + if (GET_CODE (op0) == REG && GET_CODE (op1) == CONST_INT) + { + fprintf (file, "[%s+", reg_names[REGNO (op0)]); + output_addr_const (file, op1); + fputs ("]", file); + } + else + fatal_insn ("invalid address in operand", addr); + break; + } + case MEM: + /* Fallthrough. */ + case LABEL_REF: + /* Fallthrough. */ + fatal_insn ("unsupported operand", addr); + break; + default: + output_addr_const (file, addr); + break; + } +} + +/* Add a BPF builtin function with NAME, CODE and TYPE. Return + the function decl or NULL_TREE if the builtin was not added. */ + +static tree +def_builtin (const char *name, enum bpf_builtins code, tree type) +{ + tree t + = add_builtin_function (name, type, code, BUILT_IN_MD, NULL, NULL_TREE); + + bpf_builtins[code] = t; + return t; +} + +/* Define machine-specific built-in functions. */ + +static void +bpf_init_builtins (void) +{ + /* Built-ins for calling kernel helpers. */ + + tree pt = build_pointer_type (void_type_node); + tree const_void_type + = build_qualified_type (void_type_node, TYPE_QUAL_CONST); + tree cpt = build_pointer_type (const_void_type); + tree st = short_integer_type_node; + tree ust = uint16_type_node; + tree it = integer_type_node; + tree ut = unsigned_type_node; + tree const_char_type + = build_qualified_type (char_type_node, TYPE_QUAL_CONST); + tree cst = build_pointer_type (const_char_type); + tree vt = void_type_node; + tree ult = long_unsigned_type_node; + tree u32t = uint32_type_node; + tree u64t = uint64_type_node; + tree llt = long_long_integer_type_node; + tree ullt = long_long_unsigned_type_node; + +#define TYPES build_function_type_list +#define VTYPES build_varargs_function_type_list +#define DEF_HELPER(V,D,N,T) \ + do \ + { \ + if (bpf_kernel >= (V)) \ + def_builtin ("__builtin_bpf_helper_" #N, \ + BPF_BUILTIN_HELPER_##D, \ + T); \ + } while (0); +# include "bpf-helpers.def" +#undef TYPES +#undef VTYPES +#undef DEF_HELPER + + /* Built-ins for BPF_LD_ABS and BPF_LD_IND instructions. */ + + def_builtin ("__builtin_bpf_load_byte", BPF_BUILTIN_LOAD_BYTE, + build_function_type_list (ullt, ullt, 0)); + def_builtin ("__builtin_bpf_load_half", BPF_BUILTIN_LOAD_HALF, + build_function_type_list (ullt, ullt, 0)); + def_builtin ("__builtin_bpf_load_word", BPF_BUILTIN_LOAD_WORD, + build_function_type_list (ullt, ullt, 0)); +} + +#undef TARGET_INIT_BUILTINS +#define TARGET_INIT_BUILTINS bpf_init_builtins + +/* Expand a call to a BPF-specific built-in function that was set up + with bpf_init_builtins. */ + +static rtx +bpf_expand_builtin (tree exp, rtx target, + rtx subtarget ATTRIBUTE_UNUSED, + machine_mode mode ATTRIBUTE_UNUSED, + int ignore) +{ + tree fndecl = TREE_OPERAND (CALL_EXPR_FN (exp), 0); + int code = DECL_MD_FUNCTION_CODE (fndecl); + + if (code >= 1 && code < BPF_BUILTIN_HELPER_MAX) + { + /* This is a builtin to call a kernel helper function. + + For these builtins, we just expand the function call normally + with expand_call like we would do for a libcall. The function + bpf_output_call below will then do The Right Thing (TM), + recognizing the name of the called __builtin_helper_* symbol + and emitting the corresponding CALL N instruction whenever + necessary. */ + + return expand_call (exp, target, ignore); + } + else if (code == BPF_BUILTIN_LOAD_BYTE + || code == BPF_BUILTIN_LOAD_HALF + || code == BPF_BUILTIN_LOAD_WORD) + { + /* Expand an indirect load from the sk_buff in the context. + There is just one argument to the builtin, which is the + offset. + + We try first to expand a ldabs* instruction. In case this + fails, we try a ldind* instruction. */ + + enum insn_code abs_icode + = (code == BPF_BUILTIN_LOAD_BYTE ? CODE_FOR_ldabsb + : code == BPF_BUILTIN_LOAD_HALF ? CODE_FOR_ldabsh + : CODE_FOR_ldabsw); + + enum insn_code ind_icode + = (code == BPF_BUILTIN_LOAD_BYTE ? CODE_FOR_ldindb + : code == BPF_BUILTIN_LOAD_HALF ? CODE_FOR_ldindh + : CODE_FOR_ldindw); + + tree offset_arg = CALL_EXPR_ARG (exp, 0); + struct expand_operand ops[2]; + + create_input_operand (&ops[0], expand_normal (offset_arg), + TYPE_MODE (TREE_TYPE (offset_arg))); + create_input_operand (&ops[1], const0_rtx, SImode); + + if (!maybe_expand_insn (abs_icode, 2, ops) + && !maybe_expand_insn (ind_icode, 2, ops)) + { + error ("invalid argument to built-in function"); + return gen_rtx_REG (ops[0].mode, BPF_R0); + } + + /* The result of the load is in R0. */ + return gen_rtx_REG (ops[0].mode, BPF_R0); + } + + gcc_unreachable (); +} + +#undef TARGET_EXPAND_BUILTIN +#define TARGET_EXPAND_BUILTIN bpf_expand_builtin + +/* Initialize target-specific function library calls. This is mainly + used to call library-provided soft-fp operations, since eBPF + doesn't support floating-point in "hardware". */ + +static void +bpf_init_libfuncs (void) +{ + set_conv_libfunc (sext_optab, DFmode, SFmode, + "__bpf_extendsfdf2"); + set_conv_libfunc (trunc_optab, SFmode, DFmode, + "__bpf_truncdfsf2"); + set_conv_libfunc (sfix_optab, SImode, DFmode, + "__bpf_fix_truncdfsi"); + set_conv_libfunc (sfloat_optab, DFmode, SImode, + "__bpf_floatsidf"); + set_conv_libfunc (ufloat_optab, DFmode, SImode, + "__bpf_floatunsidf"); +} + +#undef TARGET_INIT_LIBFUNCS +#define TARGET_INIT_LIBFUNCS bpf_init_libfuncs + +/* Define the mechanism that will be used for describing frame unwind + information to the debugger. In eBPF it is not possible to unwind + frames. */ + +static enum unwind_info_type +bpf_debug_unwind_info () +{ + return UI_NONE; +} + +#undef TARGET_DEBUG_UNWIND_INFO +#define TARGET_DEBUG_UNWIND_INFO bpf_debug_unwind_info + +/* Output assembly directives to assemble data of various sized and + alignments. */ + +#undef TARGET_ASM_BYTE_OP +#define TARGET_ASM_BYTE_OP "\t.byte\t" +#undef TARGET_ASM_ALIGNED_HI_OP +#define TARGET_ASM_ALIGNED_HI_OP "\t.half\t" +#undef TARGET_ASM_ALIGNED_SI_OP +#define TARGET_ASM_ALIGNED_SI_OP "\t.word\t" +#undef TARGET_ASM_ALIGNED_DI_OP +#define TARGET_ASM_ALIGNED_DI_OP "\t.dword\t" + +/* Finally, build the GCC target. */ + +struct gcc_target targetm = TARGET_INITIALIZER; + +#include "gt-bpf.h" |