nooc

commit 509c198f3ffb2130e492465f74be59c4a5b551e9
parent 4108fc4dede83faa443c8d50e17284c7b7f0abc2
Author: Nihal Jere <nihal@nihaljere.xyz>
Date:   Thu, 20 Jan 2022 14:37:20 -0600

x64: handle backward jumps

Rather than using the `end_label` parameter, since we keep track of
label locations now, we can just determine the label location and
use that value as the end instruction in emitblock.

Diffstat:
M
ir.c
 | 
26
+++++++++++++++++---------
M
x64.c
 | 
23
+++++++++++++----------

2 files changed, 30 insertions(+), 19 deletions(-)
diff --git a/ir.c b/ir.c
@@ -19,6 +19,7 @@ extern struct assgns assgns;
 extern struct toplevel toplevel;
 
 #define STARTINS(op, val, valtype) putins((out), (op), (val), (valtype)) ; curi++ ;
+#define LABEL(l) array_addlit((&out->labels), reali); STARTINS(IR_LABEL, l, VT_LABEL);
 #define NEWTMP tmpi++; interval.start = curi + 1; interval.end = curi + 1; array_add((&out->temps), interval);
 
 #define PTRSIZE 8
@@ -28,6 +29,7 @@ extern struct target targ;
 static uint64_t tmpi;
 static uint64_t labeli;
 static uint64_t curi;
+static uint64_t reali;
 static struct temp interval;
 static uint16_t regs; // used register bitfield
 
@@ -139,12 +141,12 @@ putins(struct iproc *out, int op, uint64_t val, int valtype)
 	}
 
 	array_add(out, ins);
+	reali++;
 }
 
 static uint64_t
 bumplabel(struct iproc *out)
 {
-	array_add((&out->labels), curi);
 	return labeli++;
 }
 
@@ -193,7 +195,7 @@ static int
 genexpr(struct iproc *out, size_t expri, uint64_t *val)
 {
 	struct expr *expr = &exprs.data[expri];
-	uint64_t temp2 = 0;
+	uint64_t temp2 = 0, temp;
 	switch (expr->kind) {
 	case EXPR_LIT:
 		switch (expr->class) {
@@ -307,16 +309,21 @@ genexpr(struct iproc *out, size_t expri, uint64_t *val)
 	case EXPR_COND: {
 		uint64_t condtmp;
 		int valtype = genexpr(out, expr->d.cond.cond, &condtmp);
-		size_t elselabel = bumplabel(out);
 		size_t endlabel = bumplabel(out);
-		STARTINS(IR_CONDJUMP, elselabel, VT_LABEL);
-		putins(out, IR_EXTRA, condtmp, valtype);
-		genblock(out, &expr->d.cond.bif);
-		STARTINS(IR_JUMP, endlabel, VT_LABEL);
 		if (expr->d.cond.belse.len) {
-			putins(out, IR_LABEL, elselabel, VT_LABEL);
+			size_t elselabel = bumplabel(out);
+			STARTINS(IR_CONDJUMP, elselabel, VT_LABEL);
+			putins(out, IR_EXTRA, condtmp, valtype);
+			genblock(out, &expr->d.cond.bif);
+			STARTINS(IR_JUMP, endlabel, VT_LABEL);
+			LABEL(elselabel);
 			genblock(out, &expr->d.cond.belse);
-			putins(out, IR_LABEL, endlabel, VT_LABEL);
+			LABEL(endlabel);
+		} else {
+			STARTINS(IR_CONDJUMP, endlabel, VT_LABEL);
+			putins(out, IR_EXTRA, condtmp, valtype);
+			genblock(out, &expr->d.cond.bif);
+			LABEL(endlabel);
 		}
 		return VT_EMPTY;
 	}
@@ -424,6 +431,7 @@ size_t
 genproc(struct decl *decl, struct proc *proc)
 {
 	tmpi = labeli = curi = 1;
+	reali = 0;
 	regs = targ.reserved;
 	struct type *type;
 	struct iproc iproc = {
diff --git a/x64.c b/x64.c
@@ -795,14 +795,14 @@ emitsyscall(struct data *text, uint8_t paramcount)
 }
 
 size_t
-emitblock(struct data *text, struct iproc *proc, struct instr *start, struct instr *end, uint64_t end_label, uint16_t active, uint16_t curi)
+emitblock(struct data *text, struct iproc *proc, struct instr *start, struct instr *end, uint16_t active, uint16_t curi)
 {
 	struct instr *ins = start ? start : proc->data;
 	end = end ? end : &proc->data[proc->len];
 
 	uint64_t dest, src, size, count, label;
 	int64_t offset;
-	uint64_t localalloc = 0, curlabel = 0;
+	uint64_t localalloc = 0;
 
 	size_t total = 0;
 	if (!start) {
@@ -820,11 +820,14 @@ emitblock(struct data *text, struct iproc *proc, struct instr *start, struct ins
 				active |= 1 << proc->temps.data[j].reg;
 		}
 		switch (ins->op) {
-		// FIXME: we don't handle jumps backward yet
 		case IR_JUMP:
 			assert(ins->valtype == VT_LABEL);
 			label = ins->val;
-			total += jmp(text, emitblock(NULL, proc, ins + 1, end, label, active, curi));
+			if (ins < &proc->data[proc->labels.data[label]]) {
+				total += jmp(text, emitblock(NULL, proc, ins + 1, &proc->data[proc->labels.data[label]], active, curi));
+			} else {
+				total += jmp(text, emitblock(NULL, proc, start, &proc->data[proc->labels.data[label]], 0, 0) - total - 2); // FIXME: 2 = size of short jump
+			}
 			NEXT;
 			break;
 		case IR_CONDJUMP:
@@ -835,7 +838,11 @@ emitblock(struct data *text, struct iproc *proc, struct instr *start, struct ins
 			assert(ins->op == IR_EXTRA);
 			assert(ins->valtype == VT_TEMP);
 			total += cmp_r8_imm(text, proc->temps.data[ins->val].reg, 0);
-			total += je(text, emitblock(NULL, proc, ins + 1, end, label, active, curi));
+			if (ins < &proc->data[proc->labels.data[label]]) {
+				total += je(text, emitblock(NULL, proc, ins + 1, &proc->data[proc->labels.data[label]], active, curi));
+			} else {
+				total += je(text, emitblock(NULL, proc, start, &proc->data[proc->labels.data[label]], 0, 0)- total - 2); // FIXME: 2 = size of short jump
+			}
 			NEXT;
 			break;
 		case IR_RETURN:
@@ -1008,10 +1015,6 @@ emitblock(struct data *text, struct iproc *proc, struct instr *start, struct ins
 			break;
 		case IR_LABEL:
 			assert(ins->valtype == VT_LABEL);
-			if (ins->val == end_label)
-				goto done;
-
-			curlabel = ins->val;
 			NEXT;
 			break;
 		case IR_IMM:
@@ -1029,5 +1032,5 @@ done:
 size_t
 emitproc(struct data *text, struct iproc *proc)
 {
-	return emitblock(text, proc, NULL, NULL, 0, 0, 0);
+	return emitblock(text, proc, NULL, NULL, 0, 0);
 }