ORCA-C/DAG2.pas

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{$optimize 7}
{---------------------------------------------------------------}
{ }
{ DAG Creation }
{ }
{ Places intermediate codes into DAGs and trees. }
{ }
{---------------------------------------------------------------}
unit DAG;
interface
{$segment 'cg'}
{$LibPrefix '0/obj/'}
uses CCommon, CGI, CGC, Gen;
{---------------------------------------------------------------}
procedure DAG (code: icptr);
{ place an op code in a DAG or tree }
{ }
{ parameters: }
{ code - opcode }
{---------------------------------------------------------------}
implementation
var
maxLoc: integer; {max local label number used by compiler}
{-- External unsigned math routines; imported from Expression.pas --}
function udiv (x,y: longint): longint; extern;
function umod (x,y: longint): longint; extern;
function umul (x,y: longint): longint; extern;
{---------------------------------------------------------------}
procedure DAG {code: icptr};
{ place an op code in a DAG or tree }
{ }
{ parameters: }
{ code - opcode }
var
temp: icptr; {temp node}
procedure Generate;
{ generate the code for the current procedure }
var
op: icptr; {temp opcode pointers}
procedure BasicBlocks;
{ Break the code up into basic blocks }
var
blast: blockPtr; {last block pointer}
bp: blockPtr; {current block pointer}
cb: icptr; {last code in block pointer}
cp: icptr; {current code pointer}
begin {BasicBlocks}
cp := DAGhead;
DAGblocks := nil;
if cp <> nil then begin
bp := pointer(Calloc(sizeof(block)));
DAGblocks := bp;
blast := bp;
bp^.code := cp;
cb := cp;
cp := cp^.next;
cb^.next := nil;
while cp <> nil do
{labels start a new block}
if cp^.opcode = dc_lab then begin
Spin;
bp := pointer(Calloc(sizeof(block)));
bp^.last := blast;
blast^.next := bp;
blast := bp;
bp^.code := cp;
cb := cp;
cp := cp^.next;
cb^.next := nil;
end {if}
{conditionals are followed by a new block}
else if cp^.opcode in [pc_fjp, pc_tjp, pc_ujp, pc_ret, pc_xjp] then
begin
Spin;
while cp^.next^.opcode = pc_add do begin
cb^.next := cp;
cb := cp;
cp := cp^.next;
cb^.next := nil;
end; {while}
cb^.next := cp;
cb := cp;
cp := cp^.next;
cb^.next := nil;
bp := pointer(Calloc(sizeof(block)));
bp^.last := blast;
blast^.next := bp;
blast := bp;
bp^.code := cp;
cb := cp;
cp := cp^.next;
cb^.next := nil;
end {else if}
else begin {all other statements get added to a block}
cb^.next := cp;
cb := cp;
cp := cp^.next;
cb^.next := nil;
end; {else}
end; {if}
end; {BasicBlocks}
begin {Generate}
BasicBlocks; {build the basic blocks}
Gen(DAGblocks); {generate native code}
DAGhead := nil; {reset the DAG pointers}
end; {Generate}
procedure Push (code: icptr);
{ place a node on the operation stack }
{ }
{ parameters: }
{ code - node }
begin {Push}
code^.next := DAGhead;
DAGhead := code;
end; {Push}
function Pop: icptr;
{ pop a node from the operation stack }
{ }
{ returns: node pointer or nil }
var
node: icptr; {node poped}
tn: icptr; {temp node}
begin {Pop}
node := DAGhead;
if node = nil then
Error(cge1)
else begin
DAGhead := node^.next;
node^.next := nil;
end; {else}
if node^.opcode = dc_loc then begin
tn := node;
node := Pop;
Push(tn);
end; {if}
Pop := node;
end; {Pop}
procedure Reverse;
{ Reverse the operation stack }
var
list, temp: icptr; {work pointers}
begin {Reverse}
list := nil;
while DAGhead <> nil do begin
temp := DAGhead;
DAGhead := temp^.next;
temp^.next := list;
list := temp;
end; {while}
DAGhead := list;
end; {Reverse}
begin {DAG}
case code^.opcode of
pc_bnt, pc_bnl, pc_cnv, pc_dec, pc_inc, pc_ind, pc_lbf, pc_lbu,
pc_ngi, pc_ngl, pc_ngr, pc_not, pc_stk, pc_cop, pc_cpo, pc_tl1,
pc_sro, pc_str, pc_fjp, pc_tjp, pc_xjp, pc_cup, pc_pop, pc_iil,
pc_ili, pc_idl, pc_ild:
begin
code^.left := Pop;
Push(code);
end;
pc_adi, pc_adl, pc_adr, pc_and, pc_lnd, pc_bnd, pc_bal, pc_bno,
pc_bor, pc_blr, pc_bxr, pc_blx, pc_cbf, pc_cpi, pc_dvi, pc_mov,
pc_udi, pc_dvl, pc_udl, pc_dvr, pc_equ, pc_geq, pc_grt, pc_leq,
pc_les, pc_neq, pc_ior, pc_lor, pc_ixa, pc_mod, pc_uim, pc_mdl,
pc_ulm, pc_mpi, pc_umi, pc_mpl, pc_uml, pc_mpr, pc_psh, pc_sbi,
pc_sbl, pc_sbr, pc_shl, pc_sll, pc_shr, pc_usr, pc_slr, pc_vsr,
pc_tri, pc_sbf, pc_sto, pc_cui:
begin
code^.right := Pop;
code^.left := Pop;
Push(code);
end;
pc_gil, pc_gli, pc_gdl, pc_gld, pc_lil, pc_lli, pc_ldl, pc_lld,
pc_lad, pc_lao, pc_lca, pc_lda, pc_ldc, pc_ldo, pc_lod, pc_nop,
dc_cns, dc_glb, dc_dst, pc_lnm, pc_nam, pc_nat, dc_lab, pc_add,
pc_ujp, dc_pin, pc_ent, pc_ret, dc_sym:
Push(code);
pc_cnn:
begin
code^.opcode := pc_cnv;
temp := Pop;
code^.left := Pop;
Push(code);
Push(temp);
end;
dc_loc: begin
Push(code);
if code^.r > maxLoc then
maxLoc := code^.r;
end;
dc_prm: begin
Push(code);
if code^.s > maxLoc then
maxLoc := code^.s;
end;
dc_str: begin
Push(code);
maxLoc := 0;
end;
dc_enp: begin
Push(code);
Reverse;
Generate;
end;
otherwise: Error(cge1); {invalid opcode}
end; {case}
end; {DAG}
end.