frame size > StackBig support

R=rsc
http://go/go-review/1015010

diff --git a/src/cmd/5l/noop.c b/src/cmd/5l/noop.c
index e932750b54aa64ed6c59740bf35e14cf813d687c..f67deb821ff93e8677481ff851880b0e3fb56901 100644 (file)
--- a/src/cmd/5l/noop.c
+++ b/src/cmd/5l/noop.c
@@ -360,7 +360,7 @@ noops(void)
                                // CMP                  R1, $-autosize(SP)
                                // MOVW.LO              $autosize, R1
                                // MOVW.LO              $args, R2
-                               // MOVW.W.LO            R14, R3
+                               // MOVW.LO              R14, R3
                                // BL.LO                        runtime·morestack(SB) // modifies LR
                                // MOVW.W               R14,$-autosize(SP)
 
@@ -403,7 +403,7 @@ noops(void)
                                p->to.type = D_REG;
                                p->to.reg = 2;
 
-                               // MOVW.W.LO    R14, R3
+                               // MOVW.LO      R14, R3
                                p = appendp(p);
                                p->as = AMOVW;
                                p->scond = C_SCOND_LO;
@@ -430,11 +430,53 @@ noops(void)
                                p->to.offset = -autosize;
                                p->to.reg = REGSP;
                        } else { // > StackBig
-                               // MOVW.W               R14,$-4(SP)
-                               // MOVW                 $(args << 24 | autosize), R1
-                               // BL                   callmorestack(SB)
-                               // TODO(kaib): Fix large stacks, don't use packing
-                               diag("StackBig broken");
+                               // MOVW         $autosize, R1
+                               // MOVW         $args, R2
+                               // MOVW         R14, R3
+                               // BL                   runtime·morestack(SB) // modifies LR
+                               // MOVW.W               R14,$-autosize(SP)
+
+                               // MOVW         $autosize, R1
+                               p = appendp(p);
+                               p->as = AMOVW;
+                               p->from.type = D_CONST;
+                               p->from.offset = autosize;
+                               p->to.type = D_REG;
+                               p->to.reg = 1;
+
+                               // MOVW         $args +4, R2
+                               // also need to store the extra 4 bytes.
+                               p = appendp(p);
+                               p->as = AMOVW;
+                               p->from.type = D_CONST;
+                               p->from.offset = (curtext->to.offset2 & ~7) + 4;
+                               p->to.type = D_REG;
+                               p->to.reg = 2;
+
+                               // MOVW R14, R3
+                               p = appendp(p);
+                               p->as = AMOVW;
+                               p->from.type = D_REG;
+                               p->from.reg = REGLINK;
+                               p->to.type = D_REG;
+                               p->to.reg = 3;
+
+                               // BL           runtime·morestack(SB) // modifies LR
+                               p = appendp(p);
+                               p->as = ABL;
+                               p->to.type = D_BRANCH;
+                               p->to.sym = symmorestack;
+                               p->cond = pmorestack;
+
+                               // MOVW.W               R14,$-autosize(SP)
+                               p = appendp(p);
+                               p->as = AMOVW;
+                               p->scond |= C_WBIT;
+                               p->from.type = D_REG;
+                               p->from.reg = REGLINK;
+                               p->to.type = D_OREG;
+                               p->to.offset = -autosize;
+                               p->to.reg = REGSP;
                        }
                        break;