diff options
Diffstat (limited to 'gcc/explow.c')
| -rw-r--r-- | gcc/explow.c | 74 |
1 files changed, 65 insertions, 9 deletions
diff --git a/gcc/explow.c b/gcc/explow.c index 2024b53..21af58a 100644 --- a/gcc/explow.c +++ b/gcc/explow.c @@ -1,6 +1,6 @@ /* Subroutines for manipulating rtx's in semantically interesting ways. Copyright (C) 1987, 1991, 1994, 1995, 1996, 1997, 1998, - 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008 + 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010 Free Software Foundation, Inc. This file is part of GCC. @@ -1146,6 +1146,7 @@ allocate_dynamic_stack_space (rtx size, rtx target, int known_align, { HOST_WIDE_INT stack_usage_size = -1; bool known_align_valid = true; + rtx final_label, final_target; /* If we're asking for zero bytes, it doesn't matter what we point to since we can't dereference it. But return a reasonable @@ -1284,6 +1285,14 @@ allocate_dynamic_stack_space (rtx size, rtx target, int known_align, } } + /* Don't use a TARGET that isn't a pseudo or is the wrong mode. */ + if (target == 0 || !REG_P (target) + || REGNO (target) < FIRST_PSEUDO_REGISTER + || GET_MODE (target) != Pmode) + target = gen_reg_rtx (Pmode); + + mark_reg_pointer (target, known_align); + /* The size is supposed to be fully adjusted at this point so record it if stack usage info is requested. */ if (flag_stack_usage) @@ -1296,6 +1305,52 @@ allocate_dynamic_stack_space (rtx size, rtx target, int known_align, current_function_has_unbounded_dynamic_stack_size = 1; } + final_label = NULL_RTX; + final_target = NULL_RTX; + + /* If we are splitting the stack, we need to ask the backend whether + there is enough room on the current stack. If there isn't, or if + the backend doesn't know how to tell is, then we need to call a + function to allocate memory in some other way. This memory will + be released when we release the current stack segment. The + effect is that stack allocation becomes less efficient, but at + least it doesn't cause a stack overflow. */ + if (flag_split_stack) + { + rtx available_label, space, func; + + available_label = NULL_RTX; + +#ifdef HAVE_split_stack_space_check + if (HAVE_split_stack_space_check) + { + available_label = gen_label_rtx (); + + /* This instruction will branch to AVAILABLE_LABEL if there + are SIZE bytes available on the stack. */ + emit_insn (gen_split_stack_space_check (size, available_label)); + } +#endif + + func = init_one_libfunc ("__morestack_allocate_stack_space"); + + space = emit_library_call_value (func, target, LCT_NORMAL, Pmode, + 1, size, Pmode); + + if (available_label == NULL_RTX) + return space; + + final_target = gen_reg_rtx (Pmode); + mark_reg_pointer (final_target, known_align); + + emit_move_insn (final_target, space); + + final_label = gen_label_rtx (); + emit_jump (final_label); + + emit_label (available_label); + } + do_pending_stack_adjust (); /* We ought to be called always on the toplevel and stack ought to be aligned @@ -1313,14 +1368,6 @@ allocate_dynamic_stack_space (rtx size, rtx target, int known_align, else if (flag_stack_check == STATIC_BUILTIN_STACK_CHECK) probe_stack_range (STACK_CHECK_PROTECT, size); - /* Don't use a TARGET that isn't a pseudo or is the wrong mode. */ - if (target == 0 || !REG_P (target) - || REGNO (target) < FIRST_PSEUDO_REGISTER - || GET_MODE (target) != Pmode) - target = gen_reg_rtx (Pmode); - - mark_reg_pointer (target, known_align); - /* Perform the required allocation from the stack. Some systems do this differently than simply incrementing/decrementing from the stack pointer, such as acquiring the space by calling malloc(). */ @@ -1413,6 +1460,15 @@ allocate_dynamic_stack_space (rtx size, rtx target, int known_align, if (cfun->nonlocal_goto_save_area != 0) update_nonlocal_goto_save_area (); + /* Finish up the split stack handling. */ + if (final_label != NULL_RTX) + { + gcc_assert (flag_split_stack); + emit_move_insn (final_target, target); + emit_label (final_label); + target = final_target; + } + return target; } |