diff options
Diffstat (limited to 'gcc/config/i386/i386.c')
| -rw-r--r-- | gcc/config/i386/i386.c | 47 |
1 files changed, 47 insertions, 0 deletions
diff --git a/gcc/config/i386/i386.c b/gcc/config/i386/i386.c index 725a984..9017207 100644 --- a/gcc/config/i386/i386.c +++ b/gcc/config/i386/i386.c @@ -574,6 +574,7 @@ static HOST_WIDE_INT ix86_GOT_alias_set PARAMS ((void)); static void ix86_adjust_counter PARAMS ((rtx, HOST_WIDE_INT)); static rtx ix86_expand_aligntest PARAMS ((rtx, int)); static void ix86_expand_strlensi_unroll_1 PARAMS ((rtx, rtx)); +static void ix86_output_main_function_alignment_hack PARAMS ((FILE *f, int)); struct ix86_address { @@ -634,6 +635,10 @@ static int ix86_comp_type_attributes PARAMS ((tree, tree)); HOST_WIDE_INT)); # undef TARGET_ASM_FUNCTION_PROLOGUE # define TARGET_ASM_FUNCTION_PROLOGUE ix86_osf_output_function_prologue +#else +# undef TARGET_ASM_FUNCTION_PROLOGUE +# define TARGET_ASM_FUNCTION_PROLOGUE \ + ix86_output_main_function_alignment_hack #endif #undef TARGET_ASM_OPEN_PAREN @@ -10775,3 +10780,45 @@ ix86_memory_move_cost (mode, class, in) * (int) GET_MODE_SIZE (mode) / 4); } } + +/* Most of current runtimes (Jul 2001) do not align stack properly when + entering main, so emit an wrapper to align stack before the real main + code is called. + + This can eventually go if we manage to fix the runtimes or teach gcc + to dynamically align stack in main automatically. + + Adding check to configure is probably not good idea, as binarry can move + from one shared library to older. */ + +static void +ix86_output_main_function_alignment_hack (file, size) + FILE *file; + int size ATTRIBUTE_UNUSED; +{ + rtx label; + char buf[256]; + /* Check that we see main function with maximally 8 bytes of arguments. + if so, emit the hack to align stack for runtimes, where this constraint + is broken. */ + if (strcmp (cfun->name, "main")) + return; + if (cfun->pops_args || cfun->args_size > 12) + return; + if (PREFERRED_STACK_BOUNDARY <= 2) + return; + label = gen_label_rtx (); + fprintf (file, "\tpushl\t%%ebp\n"); + fprintf (file, "\tmovl\t%%esp, %%ebp\n"); + fprintf (file, "\tandl\t$0xfffffff0, %%esp\n"); + fprintf (file, "\tpushl\t%%ebp\n"); + fprintf (file, "\tpushl\t16(%%ebp)\n"); + fprintf (file, "\tpushl\t12(%%ebp)\n"); + fprintf (file, "\tpushl\t8(%%ebp)\n"); + fprintf (file, "\tcall\t"); + ASM_GENERATE_INTERNAL_LABEL (buf, "L", CODE_LABEL_NUMBER (label)); + assemble_name (file, buf); + fprintf (file, "\n\tleave\n"); + fprintf (file, "\tret\n"); + ASM_OUTPUT_INTERNAL_LABEL (file, "L", CODE_LABEL_NUMBER (label)); +} |