diff options
Diffstat (limited to 'x86_64-gen.c')
| -rw-r--r-- | x86_64-gen.c | 39 |
1 files changed, 23 insertions, 16 deletions
diff --git a/x86_64-gen.c b/x86_64-gen.c index 0b0e69e..49cfdd1 100644 --- a/x86_64-gen.c +++ b/x86_64-gen.c @@ -820,7 +820,6 @@ static const uint8_t arg_regs[REGN] = { void gfunc_call(int nb_args) { int size, align, r, args_size, i; - SValue *orig_vtop; int nb_reg_args = 0; int nb_sse_args = 0; int sse_reg, gen_reg; @@ -845,7 +844,6 @@ void gfunc_call(int nb_args) /* for struct arguments, we need to call memcpy and the function call breaks register passing arguments we are preparing. So, we process arguments which will be passed by stack first. */ - orig_vtop = vtop; gen_reg = nb_reg_args; sse_reg = nb_sse_args; @@ -861,6 +859,14 @@ void gfunc_call(int nb_args) } for(i = 0; i < nb_args; i++) { + /* Swap argument to top, it will possibly be changed here, + and might use more temps. All arguments must remain on the + stack, so that get_reg can correctly evict some of them onto + stack. We could use also use a vrott(nb_args) at the end + of this loop, but this seems faster. */ + SValue tmp = vtop[0]; + vtop[0] = vtop[-i]; + vtop[-i] = tmp; if ((vtop->type.t & VT_BTYPE) == VT_STRUCT) { size = type_size(&vtop->type, &align); /* align to stack align size */ @@ -872,18 +878,9 @@ void gfunc_call(int nb_args) r = get_reg(RC_INT); orex(1, r, 0, 0x89); /* mov %rsp, r */ o(0xe0 + REG_VALUE(r)); - { - /* following code breaks vtop[1], vtop[2], and vtop[3] */ - SValue tmp1 = vtop[1]; - SValue tmp2 = vtop[2]; - SValue tmp3 = vtop[3]; - vset(&vtop->type, r | VT_LVAL, 0); - vswap(); - vstore(); - vtop[1] = tmp1; - vtop[2] = tmp2; - vtop[3] = tmp3; - } + vset(&vtop->type, r | VT_LVAL, 0); + vswap(); + vstore(); args_size += size; } else if ((vtop->type.t & VT_BTYPE) == VT_LDOUBLE) { gv(RC_ST0); @@ -913,10 +910,14 @@ void gfunc_call(int nb_args) args_size += 8; } } - vtop--; + + /* And swap the argument back to it's original position. */ + tmp = vtop[0]; + vtop[0] = vtop[-i]; + vtop[-i] = tmp; } - vtop = orig_vtop; + /* XXX This should be superfluous. */ save_regs(0); /* save used temporary registers */ /* then, we prepare register passing arguments. @@ -953,6 +954,12 @@ void gfunc_call(int nb_args) vtop--; } + /* We shouldn't have many operands on the stack anymore, but the + call address itself is still there, and it might be in %eax + (or edx/ecx) currently, which the below writes would clobber. + So evict all remaining operands here. */ + save_regs(0); + /* Copy R10 and R11 into RDX and RCX, respectively */ if (nb_reg_args > 2) { o(0xd2894c); /* mov %r10, %rdx */ |