From efcc2e303fe5f0daff889c66dff59cfefe3859a1 Mon Sep 17 00:00:00 2001 From: Claudiu Zissulescu Date: Mon, 8 Jan 2018 11:49:14 +0100 Subject: [PATCH] [ARC] Revamp trampoline implementation The new implementation attempts to clean up the existing trampoline implementation for ARC making it to work for linux type of systems. gcc/ 2018-01-08 Claudiu Zissulescu * config/arc/arc.c (TARGET_TRAMPOLINE_ADJUST_ADDRESS): Delete. (emit_store_direct): Likewise. (arc_trampoline_adjust_address): Likewise. (arc_asm_trampoline_template): New function. (arc_initialize_trampoline): Use asm_trampoline_template. (TARGET_ASM_TRAMPOLINE_TEMPLATE): Define. * config/arc/arc.h (TRAMPOLINE_SIZE): Adjust to 16. *config/arc/arc.md (flush_icache): Delete pattern. From-SVN: r256334 --- gcc/ChangeLog | 11 ++++++ gcc/config/arc/arc.c | 90 ++++++++++++++++++++----------------------- gcc/config/arc/arc.h | 2 +- gcc/config/arc/arc.md | 9 ----- 4 files changed, 54 insertions(+), 58 deletions(-) diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 75bf6b88e6b..b176f6ee0c3 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,14 @@ +2018-01-08 Claudiu Zissulescu + + * config/arc/arc.c (TARGET_TRAMPOLINE_ADJUST_ADDRESS): Delete. + (emit_store_direct): Likewise. + (arc_trampoline_adjust_address): Likewise. + (arc_asm_trampoline_template): New function. + (arc_initialize_trampoline): Use asm_trampoline_template. + (TARGET_ASM_TRAMPOLINE_TEMPLATE): Define. + * config/arc/arc.h (TRAMPOLINE_SIZE): Adjust to 16. + * config/arc/arc.md (flush_icache): Delete pattern. + 2018-01-08 Claudiu Zissulescu * config/arc/arc-c.def (__ARC_UNALIGNED__): New define. diff --git a/gcc/config/arc/arc.c b/gcc/config/arc/arc.c index 67119113db9..c7947912bde 100644 --- a/gcc/config/arc/arc.c +++ b/gcc/config/arc/arc.c @@ -548,8 +548,6 @@ static void arc_finalize_pic (void); #define TARGET_TRAMPOLINE_INIT arc_initialize_trampoline -#define TARGET_TRAMPOLINE_ADJUST_ADDRESS arc_trampoline_adjust_address - #define TARGET_CAN_ELIMINATE arc_can_eliminate #define TARGET_FRAME_POINTER_REQUIRED arc_frame_pointer_required @@ -3672,69 +3670,62 @@ output_shift (rtx *operands) /* Nested function support. */ -/* Directly store VALUE into memory object BLOCK at OFFSET. */ +/* Output assembler code for a block containing the constant parts of + a trampoline, leaving space for variable parts. A trampoline looks + like this: + + ld_s r12,[pcl,8] + ld r11,[pcl,12] + j_s [r12] + .word function's address + .word static chain value + +*/ static void -emit_store_direct (rtx block, int offset, int value) +arc_asm_trampoline_template (FILE *f) { - emit_insn (gen_store_direct (adjust_address (block, SImode, offset), - force_reg (SImode, - gen_int_mode (value, SImode)))); + asm_fprintf (f, "\tld_s\t%s,[pcl,8]\n", ARC_TEMP_SCRATCH_REG); + asm_fprintf (f, "\tld\t%s,[pcl,12]\n", reg_names[STATIC_CHAIN_REGNUM]); + asm_fprintf (f, "\tj_s\t[%s]\n", ARC_TEMP_SCRATCH_REG); + assemble_aligned_integer (UNITS_PER_WORD, const0_rtx); + assemble_aligned_integer (UNITS_PER_WORD, const0_rtx); } /* Emit RTL insns to initialize the variable parts of a trampoline. - FNADDR is an RTX for the address of the function's pure code. - CXT is an RTX for the static chain value for the function. */ -/* With potentially multiple shared objects loaded, and multiple stacks - present for multiple thereds where trampolines might reside, a simple - range check will likely not suffice for the profiler to tell if a callee - is a trampoline. We a speedier check by making the trampoline start at - an address that is not 4-byte aligned. - A trampoline looks like this: - - nop_s 0x78e0 -entry: - ld_s r12,[pcl,12] 0xd403 - ld r11,[pcl,12] 0x170c 700b - j_s [r12] 0x7c00 - nop_s 0x78e0 + FNADDR is an RTX for the address of the function's pure code. CXT + is an RTX for the static chain value for the function. The fastest trampoline to execute for trampolines within +-8KB of CTX would be: + add2 r11,pcl,s12 j [limm] 0x20200f80 limm - and that would also be faster to write to the stack by computing the offset - from CTX to TRAMP at compile time. However, it would really be better to - get rid of the high cost of cache invalidation when generating trampolines, - which requires that the code part of trampolines stays constant, and - additionally either - - making sure that no executable code but trampolines is on the stack, - no icache entries linger for the area of the stack from when before the - stack was allocated, and allocating trampolines in trampoline-only - cache lines - or - - allocate trampolines fram a special pool of pre-allocated trampolines. */ + + and that would also be faster to write to the stack by computing + the offset from CTX to TRAMP at compile time. However, it would + really be better to get rid of the high cost of cache invalidation + when generating trampolines, which requires that the code part of + trampolines stays constant, and additionally either making sure + that no executable code but trampolines is on the stack, no icache + entries linger for the area of the stack from when before the stack + was allocated, and allocating trampolines in trampoline-only cache + lines or allocate trampolines fram a special pool of pre-allocated + trampolines. */ static void arc_initialize_trampoline (rtx tramp, tree fndecl, rtx cxt) { rtx fnaddr = XEXP (DECL_RTL (fndecl), 0); - emit_store_direct (tramp, 0, TARGET_BIG_ENDIAN ? 0x78e0d403 : 0xd40378e0); - emit_store_direct (tramp, 4, TARGET_BIG_ENDIAN ? 0x170c700b : 0x700b170c); - emit_store_direct (tramp, 8, TARGET_BIG_ENDIAN ? 0x7c0078e0 : 0x78e07c00); - emit_move_insn (adjust_address (tramp, SImode, 12), fnaddr); - emit_move_insn (adjust_address (tramp, SImode, 16), cxt); - emit_insn (gen_flush_icache (adjust_address (tramp, SImode, 0))); -} - -/* Allow the profiler to easily distinguish trampolines from normal - functions. */ - -static rtx -arc_trampoline_adjust_address (rtx addr) -{ - return plus_constant (Pmode, addr, 2); + emit_block_move (tramp, assemble_trampoline_template (), + GEN_INT (TRAMPOLINE_SIZE), BLOCK_OP_NORMAL); + emit_move_insn (adjust_address (tramp, SImode, 8), fnaddr); + emit_move_insn (adjust_address (tramp, SImode, 12), cxt); + emit_library_call (gen_rtx_SYMBOL_REF (Pmode, "__clear_cache"), + LCT_NORMAL, VOIDmode, XEXP (tramp, 0), Pmode, + plus_constant (Pmode, XEXP (tramp, 0), TRAMPOLINE_SIZE), + Pmode); } /* This is set briefly to 1 when we output a ".as" address modifer, and then @@ -10870,6 +10861,9 @@ arc_cannot_substitute_mem_equiv_p (rtx) #undef TARGET_CANNOT_SUBSTITUTE_MEM_EQUIV_P #define TARGET_CANNOT_SUBSTITUTE_MEM_EQUIV_P arc_cannot_substitute_mem_equiv_p +#undef TARGET_ASM_TRAMPOLINE_TEMPLATE +#define TARGET_ASM_TRAMPOLINE_TEMPLATE arc_asm_trampoline_template + struct gcc_target targetm = TARGET_INITIALIZER; #include "gt-arc.h" diff --git a/gcc/config/arc/arc.h b/gcc/config/arc/arc.h index ae3d9c1c75b..02a4b64c70f 100644 --- a/gcc/config/arc/arc.h +++ b/gcc/config/arc/arc.h @@ -829,7 +829,7 @@ extern int arc_initial_elimination_offset(int from, int to); /* Trampolines. */ /* Length in units of the trampoline for entering a nested function. */ -#define TRAMPOLINE_SIZE 20 +#define TRAMPOLINE_SIZE 16 /* Alignment required for a trampoline in bits . */ /* For actual data alignment we just need 32, no more than the stack; diff --git a/gcc/config/arc/arc.md b/gcc/config/arc/arc.md index 812a98b539c..10b027a89af 100644 --- a/gcc/config/arc/arc.md +++ b/gcc/config/arc/arc.md @@ -4325,15 +4325,6 @@ (set_attr "iscompact" "true") (set_attr "length" "2")]) -;; Special pattern to flush the icache. -;; ??? Not sure what to do here. Some ARC's are known to support this. - -(define_insn "flush_icache" - [(unspec_volatile [(match_operand:SI 0 "memory_operand" "m")] 0)] - "" - "* return \"\";" - [(set_attr "type" "misc")]) - ;; Split up troublesome insns for better scheduling. ;; Peepholes go at the end. -- 2.30.2