From 327736b3a6e77b201fffebd3cc207662e823d3a5 Mon Sep 17 00:00:00 2001
From: Quentin Carbonneaux <quentin@c9x.me>
Date: Thu, 19 Dec 2024 15:10:52 +0100
Subject: [PATCH] handle large hfas correctly on arm64

---
 arm64/abi.c   | 36 +++++++++++++++++++-----------------
 test/abi8.ssa | 21 +++++++++++++++++++++
 2 files changed, 40 insertions(+), 17 deletions(-)

diff --git a/arm64/abi.c b/arm64/abi.c
index abc02d9..b9e6a14 100644
--- a/arm64/abi.c
+++ b/arm64/abi.c
@@ -90,7 +90,7 @@ isfloatv(Typ *t, char *cls)
 static void
 typclass(Class *c, Typ *t, int *gp, int *fp)
 {
-	uint64_t sz;
+	uint64_t sz, hfasz;
 	uint n;
 
 	sz = (t->size + 7) & -8;
@@ -103,7 +103,21 @@ typclass(Class *c, Typ *t, int *gp, int *fp)
 	if (t->align > 3)
 		err("alignments larger than 8 are not supported");
 
-	if (t->isdark || sz > 16 || sz == 0) {
+	c->size = sz;
+	c->hfa.base = Kx;
+	c->ishfa = isfloatv(t, &c->hfa.base);
+	hfasz = t->size/(KWIDE(c->hfa.base) ? 8 : 4);
+	c->ishfa &= !t->isdark && hfasz <= 4;
+	c->hfa.size = hfasz;
+
+	if (c->ishfa) {
+		for (n=0; n<hfasz; n++, c->nfp++) {
+			c->reg[n] = *fp++;
+			c->cls[n] = c->hfa.base;
+		}
+		c->nreg = n;
+	}
+	else if (t->isdark || sz > 16 || sz == 0) {
 		/* large structs are replaced by a
 		 * pointer to some caller-allocated
 		 * memory */
@@ -112,26 +126,14 @@ typclass(Class *c, Typ *t, int *gp, int *fp)
 		c->ngp = 1;
 		*c->reg = *gp;
 		*c->cls = Kl;
-		return;
 	}
-
-	c->size = sz;
-	c->hfa.base = Kx;
-	c->ishfa = isfloatv(t, &c->hfa.base);
-	c->hfa.size = t->size/(KWIDE(c->hfa.base) ? 8 : 4);
-
-	if (c->ishfa)
-		for (n=0; n<c->hfa.size; n++, c->nfp++) {
-			c->reg[n] = *fp++;
-			c->cls[n] = c->hfa.base;
-		}
-	else
+	else {
 		for (n=0; n<sz/8; n++, c->ngp++) {
 			c->reg[n] = *gp++;
 			c->cls[n] = Kl;
 		}
-
-	c->nreg = n;
+		c->nreg = n;
+	}
 }
 
 static void
diff --git a/test/abi8.ssa b/test/abi8.ssa
index 85c3b73..e1e6c42 100644
--- a/test/abi8.ssa
+++ b/test/abi8.ssa
@@ -10,6 +10,7 @@ type :sd = { s, d }    # ditto
 type :ww = { w, w }    # in a single gp reg
 type :lb = { l, b }    # in two gp regs
 type :big = { b 17 }   # by reference
+type :ddd = { d, d, d} # big hfa on arm64
 
 data $ctoqbestr = { b "c->qbe(%d)", b 0 }
 data $emptystr = { b 0 }
@@ -112,6 +113,14 @@ function $qfn10(w %p0, w %p1, w %p2, w %p3, w %p4, w %p5, w %p6, w %p7, :big %p8
 	%r1 =w call $puts(l $emptystr)
 	ret
 }
+export
+function $qfn11(:ddd %p0) {
+@start
+	%r0 =w call $printf(l $ctoqbestr, ..., w 11)
+	call $pddd(l %p0)
+	%r1 =w call $puts(l $emptystr)
+	ret
+}
 
 export
 function w $main() {
@@ -128,6 +137,7 @@ function w $main() {
 	call $cfn8(w 0, w 0, w 0, w 0, w 0, w 0, w 0, w 0, :lb $lb)
 	call $cfn9(:big $big)
 	call $cfn10(w 0, w 0, w 0, w 0, w 0, w 0, w 0, w 0, :big $big, s s_10.10, l 11)
+	call $cfn11(:ddd $ddd)
 
 	ret 0
 }
@@ -142,6 +152,7 @@ function w $main() {
 # typedef struct { int w0, w1; } Sww;
 # typedef struct { long l; char b; } Slb;
 # typedef struct { char b[17]; } Sbig;
+# typedef struct { double d0, d1, d2; } Sddd;
 # Sfi1 zfi1, fi1 = { -123, 4.56 };
 # Sfi2 zfi2, fi2 = { 1.23, 456 };
 # Sfi3 zfi3, fi3 = { 3.45, 567 };
@@ -150,6 +161,7 @@ function w $main() {
 # Sww zww, ww = { -123, -456 };
 # Slb zlb, lb = { 123, 'z' };
 # Sbig zbig, big = { "abcdefhijklmnopqr" };
+# Sddd zddd, ddd = { 1.23, 45.6, 7.89 };
 # void pfi1(Sfi1 *s) { printf(" { %d, %g }", s->h, s->s); }
 # void pfi2(Sfi2 *s) { printf(" { %g, %d }", s->s, s->w); }
 # void pfi3(Sfi3 *s) { printf(" { %g, %d }", s->s, s->u.w); }
@@ -158,6 +170,7 @@ function w $main() {
 # void pww(Sww *s) { printf(" { %d, %d }", s->w0, s->w1); }
 # void plb(Slb *s) { printf(" { %ld, '%c' }", s->l, s->b); }
 # void pbig(Sbig *s) { printf(" \"%.17s\"", s->b); }
+# void pddd(Sddd *s) { printf(" { %g, %g, %g }", s->d0, s->d1, s->d2); }
 # void pw(int w) { printf(" %d", w); }
 # void pl(long l) { printf(" %ld", l); }
 # void ps(float s) { printf(" %g", s); }
@@ -229,6 +242,12 @@ function w $main() {
 # 	pbig(&p8); ps(p9); pl(p10); puts("");
 # 	qfn10(p0, p1, p2, p3, p4, p5, p6, p7, p8, p9, p10);
 # }
+# extern void qfn11(Sddd);
+# void cfn11(Sddd p0) {
+# 	printf("qbe->c(%d)", 11);
+# 	pddd(&p0); puts("");
+# 	qfn11(p0);
+# }
 # <<<
 
 # >>> output
@@ -254,4 +273,6 @@ function w $main() {
 # c->qbe(9) "abcdefhijklmnopqr"
 # qbe->c(10) "abcdefhijklmnopqr" 10.1 11
 # c->qbe(10) "abcdefhijklmnopqr" 10.1 11
+# qbe->c(11) { 1.23, 45.6, 7.89 }
+# c->qbe(11) { 1.23, 45.6, 7.89 }
 # <<<
-- 
2.11.4.GIT