X-Git-Url: http://git.sourceforge.jp/view?a=blobdiff_plain;f=gcc%2Fsibcall.c;h=bfad98adac3bb9e5e4bbcb0d69c64e132bc69c95;hb=d54ddafb6fff32e47a2d02f5110ca93f963367a6;hp=8f52da0b2b6de4d0efc5f4b4c1364d1ffc8367ee;hpb=e902cfce7230c8341c122605b7bde15f1c4f0900;p=pf3gnuchains%2Fgcc-fork.git diff --git a/gcc/sibcall.c b/gcc/sibcall.c index 8f52da0b2b6..bfad98adac3 100644 --- a/gcc/sibcall.c +++ b/gcc/sibcall.c @@ -1,5 +1,5 @@ /* Generic sibling call optimization support - Copyright (C) 1999, 2000, 2001 Free Software Foundation, Inc. + Copyright (C) 1999, 2000, 2001, 2002 Free Software Foundation, Inc. This file is part of GCC. @@ -20,6 +20,8 @@ Software Foundation, 59 Temple Place - Suite 330, Boston, MA #include "config.h" #include "system.h" +#include "coretypes.h" +#include "tm.h" #include "rtl.h" #include "regs.h" @@ -31,6 +33,7 @@ Software Foundation, 59 Temple Place - Suite 330, Boston, MA #include "basic-block.h" #include "output.h" #include "except.h" +#include "tree.h" /* In case alternate_exit_block contains copy from pseudo, to return value, record the pseudo here. In such case the pseudo must be set to function @@ -53,7 +56,7 @@ static rtx skip_unreturned_value PARAMS ((rtx)); /* Examine a CALL_PLACEHOLDER pattern and determine where the call's return value is located. P_HARD_RETURN receives the hard register that the function used; P_SOFT_RETURN receives the pseudo register - that the sequence used. Return non-zero if the values were located. */ + that the sequence used. Return nonzero if the values were located. */ static int identify_call_return_value (cp, p_hard_return, p_soft_return) @@ -85,7 +88,7 @@ identify_call_return_value (cp, p_hard_return, p_soft_return) /* If we didn't get a single hard register (e.g. a parallel), give up. */ if (GET_CODE (hard) != REG) return 0; - + /* Stack adjustment done after call may appear here. */ insn = skip_stack_adjustment (insn); if (! insn) @@ -100,7 +103,7 @@ identify_call_return_value (cp, p_hard_return, p_soft_return) insn = NEXT_INSN (insn); if (! insn) return 0; - + /* We're looking for a source of the hard return register. */ set = single_set (insn); if (! set || SET_SRC (set) != hard) @@ -167,7 +170,7 @@ skip_copy_to_return_value (orig_insn) /* The destination must be the same as the called function's return value to ensure that any return value is put in the same place by the - current function and the function we're calling. + current function and the function we're calling. Further, the source must be the same as the pseudo into which the called function's return value was copied. Otherwise we're returning @@ -429,7 +432,7 @@ uses_addressof (x) } /* Scan the sequence of insns in SEQ to see if any have an ADDRESSOF - rtl expression or current_function_internal_arg_pointer occurences + rtl expression or current_function_internal_arg_pointer occurrences not enclosed within a MEM. If an ADDRESSOF expression or current_function_internal_arg_pointer is found, return nonzero, otherwise return zero. @@ -540,20 +543,20 @@ replace_call_placeholder (insn, use) sibcall_use_t use; { if (use == sibcall_use_tail_recursion) - emit_insns_before (XEXP (PATTERN (insn), 2), insn); + emit_insn_before (XEXP (PATTERN (insn), 2), insn); else if (use == sibcall_use_sibcall) - emit_insns_before (XEXP (PATTERN (insn), 1), insn); + emit_insn_before (XEXP (PATTERN (insn), 1), insn); else if (use == sibcall_use_normal) - emit_insns_before (XEXP (PATTERN (insn), 0), insn); + emit_insn_before (XEXP (PATTERN (insn), 0), insn); else - abort(); + abort (); /* Turn off LABEL_PRESERVE_P for the tail recursion label if it exists. We only had to set it long enough to keep the jump pass above from deleting it as unused. */ if (XEXP (PATTERN (insn), 3)) LABEL_PRESERVE_P (XEXP (PATTERN (insn), 3)) = 0; - + /* "Delete" the placeholder insn. */ remove_insn (insn); } @@ -572,29 +575,25 @@ optimize_sibling_and_tail_recursive_calls () { rtx insn, insns; basic_block alternate_exit = EXIT_BLOCK_PTR; - int current_function_uses_addressof; - int successful_sibling_call = 0; - int replaced_call_placeholder = 0; + bool no_sibcalls_this_function = false; + bool successful_replacement = false; + bool replaced_call_placeholder = false; edge e; insns = get_insns (); - /* We do not perform these calls when flag_exceptions is true, so this - is probably a NOP at the current time. However, we may want to support - sibling and tail recursion optimizations in the future, so let's plan - ahead and find all the EH labels. */ - find_exception_handler_labels (); - - rebuild_jump_labels (insns); - /* We need cfg information to determine which blocks are succeeded - only by the epilogue. */ - find_basic_blocks (insns, max_reg_num (), 0); cleanup_cfg (CLEANUP_PRE_SIBCALL | CLEANUP_PRE_LOOP); /* If there are no basic blocks, then there is nothing to do. */ if (n_basic_blocks == 0) return; + /* If we are using sjlj exceptions, we may need to add a call to + _Unwind_SjLj_Unregister at exit of the function. Which means + that we cannot do any sibcall transformations. */ + if (USING_SJLJ_EXCEPTIONS && current_function_has_exception_handlers ()) + no_sibcalls_this_function = true; + return_value_pseudo = NULL_RTX; /* Find the exit block. @@ -613,7 +612,7 @@ optimize_sibling_and_tail_recursive_calls () /* Walk forwards through the last normal block and see if it does nothing except fall into the exit block. */ - for (insn = BLOCK_HEAD (n_basic_blocks - 1); + for (insn = EXIT_BLOCK_PTR->prev_bb->head; insn; insn = NEXT_INSN (insn)) { @@ -655,7 +654,7 @@ optimize_sibling_and_tail_recursive_calls () /* If the function uses ADDRESSOF, we can't (easily) determine at this point if the value will end up on the stack. */ - current_function_uses_addressof = sequence_uses_addressof (insns); + no_sibcalls_this_function |= sequence_uses_addressof (insns); /* Walk the insn chain and find any CALL_PLACEHOLDER insns. We need to select one of the insn sequences attached to each CALL_PLACEHOLDER. @@ -679,24 +678,22 @@ optimize_sibling_and_tail_recursive_calls () sibling call optimizations, but not tail recursion. Similarly if we use varargs or stdarg since they implicitly may take the address of an argument. */ - if (current_function_calls_alloca - || current_function_varargs || current_function_stdarg) + if (current_function_calls_alloca || current_function_stdarg) sibcall = 0; /* See if there are any reasons we can't perform either sibling or tail call optimizations. We must be careful with stack slots - which are live at potential optimization sites. ??? The first - test is overly conservative and should be replaced. */ - if (frame_offset - /* Can't take address of local var if used by recursive call. */ - || current_function_uses_addressof + which are live at potential optimization sites. */ + if (no_sibcalls_this_function + /* ??? Overly conservative. */ + || frame_offset /* Any function that calls setjmp might have longjmp called from any called function. ??? We really should represent this properly in the CFG so that this needn't be special cased. */ || current_function_calls_setjmp /* Can't if more than one successor or single successor is not exit block. These two tests prevent tail call optimization - in the presense of active exception handlers. */ + in the presence of active exception handlers. */ || call_block->succ == NULL || call_block->succ->succ_next != NULL || (call_block->succ->dest != EXIT_BLOCK_PTR @@ -709,12 +706,13 @@ optimize_sibling_and_tail_recursive_calls () /* Select a set of insns to implement the call and emit them. Tail recursion is the most efficient, so select it over a tail/sibling call. */ - if (sibcall) - successful_sibling_call = 1; - replaced_call_placeholder = 1; - replace_call_placeholder (insn, - tailrecursion != 0 + if (sibcall || tailrecursion) + successful_replacement = true; + replaced_call_placeholder = true; + + replace_call_placeholder (insn, + tailrecursion != 0 ? sibcall_use_tail_recursion : sibcall != 0 ? sibcall_use_sibcall @@ -722,16 +720,17 @@ optimize_sibling_and_tail_recursive_calls () } } - if (successful_sibling_call) + if (successful_replacement) { rtx insn; + tree arg; /* A sibling call sequence invalidates any REG_EQUIV notes made for - this function's incoming arguments. + this function's incoming arguments. At the start of RTL generation we know the only REG_EQUIV notes in the rtl chain are those for incoming arguments, so we can safely - flush any REG_EQUIV note. + flush any REG_EQUIV note. This is (slight) overkill. We could keep track of the highest argument we clobber and be more selective in removing notes, but it @@ -741,7 +740,7 @@ optimize_sibling_and_tail_recursive_calls () /* A sibling call sequence also may invalidate RTX_UNCHANGING_P flag of some incoming arguments MEM RTLs, because it can write into those slots. We clear all those bits now. - + This is (slight) overkill, we could keep track of which arguments we actually write into. */ for (insn = get_insns (); insn; insn = NEXT_INSN (insn)) @@ -749,9 +748,19 @@ optimize_sibling_and_tail_recursive_calls () if (INSN_P (insn)) purge_mem_unchanging_flag (PATTERN (insn)); } + + /* Similarly, invalidate RTX_UNCHANGING_P for any incoming + arguments passed in registers. */ + for (arg = DECL_ARGUMENTS (current_function_decl); + arg; + arg = TREE_CHAIN (arg)) + { + if (REG_P (DECL_RTL (arg))) + RTX_UNCHANGING_P (DECL_RTL (arg)) = false; + } } - /* There may have been NOTE_INSN_BLOCK_{BEGIN,END} notes in the + /* There may have been NOTE_INSN_BLOCK_{BEGIN,END} notes in the CALL_PLACEHOLDER alternatives that we didn't emit. Rebuild the lexical block tree to correspond to the notes that still exist. */ if (replaced_call_placeholder) @@ -759,4 +768,5 @@ optimize_sibling_and_tail_recursive_calls () /* This information will be invalid after inline expansion. Kill it now. */ free_basic_block_vars (0); + free_EXPR_LIST_list (&tail_recursion_label_list); }