[dev.power64] cmd/ld, runtime: detect, fix nosplit overflows

LGTM=minux
R=minux
CC=golang-codereviews
https://codereview.appspot.com/121690043

1 files changed, 15 insertions, 18 deletions

diff --git a/src/cmd/ld/lib.c b/src/cmd/ld/lib.c
index b4134da36..5db41f9a7 100644
--- a/src/cmd/ld/lib.c
+++ b/src/cmd/ld/lib.c
@@ -1026,7 +1026,7 @@ static LSym *newstack;
 
 enum
 {
-	HasLinkRegister = (thechar == '5'),
+	HasLinkRegister = (thechar == '5' || thechar == '9'),
 };
 
 // TODO: Record enough information in new object files to
@@ -1035,7 +1035,7 @@ enum
 static int
 callsize(void)
 {
-	if(thechar == '5')
+	if(HasLinkRegister)
 		return 0;
 	return RegSize;
 }
@@ -1046,9 +1046,6 @@ dostkcheck(void)
 	Chain ch;
 	LSym *s;
 
-	if(thechar == '9')
-		return;
-	
 	morestack = linklookup(ctxt, "runtime.morestack", 0);
 	newstack = linklookup(ctxt, "runtime.newstack", 0);
 
@@ -1072,19 +1069,19 @@ dostkcheck(void)
 			continue;
 
 		if(s->nosplit) {
-		ctxt->cursym = s;
-		ch.sym = s;
-		stkcheck(&ch, 0);
-	}
+			ctxt->cursym = s;
+			ch.sym = s;
+			stkcheck(&ch, 0);
+		}
 	}
 	for(s = ctxt->textp; s != nil; s = s->next) {
 		if(!s->nosplit) {
-		ctxt->cursym = s;
-		ch.sym = s;
-		stkcheck(&ch, 0);
+			ctxt->cursym = s;
+			ch.sym = s;
+			stkcheck(&ch, 0);
+		}
 	}
 }
-}
 
 static int
 stkcheck(Chain *up, int depth)
@@ -1102,7 +1099,7 @@ stkcheck(Chain *up, int depth)
 	// function at top of safe zone once.
 	if(limit == StackLimit-callsize()) {
 		if(s->stkcheck)
-		return 0;
+			return 0;
 		s->stkcheck = 1;
 	}
 	
@@ -1161,8 +1158,8 @@ stkcheck(Chain *up, int depth)
 				// to StackLimit beyond the frame size.
 				if(strncmp(r->sym->name, "runtime.morestack", 17) == 0) {
 					limit = StackLimit + s->locals;
-					if(thechar == '5')
-						limit += 4; // saved LR
+					if(HasLinkRegister)
+						limit += RegSize;
 				}
 				break;
 
@@ -1181,7 +1178,7 @@ stkcheck(Chain *up, int depth)
 				break;
 			}
 		}
-		}
+	}
 		
 	return 0;
 }
@@ -1210,7 +1207,7 @@ stkprint(Chain *ch, int limit)
 		else
 			print("\t%d\tguaranteed after split check in %s\n", ch->limit, name);
 	} else {
-		stkprint(ch->up, ch->limit + (!HasLinkRegister)*PtrSize);
+		stkprint(ch->up, ch->limit + (!HasLinkRegister)*RegSize);
 		if(!HasLinkRegister)
 			print("\t%d\ton entry to %s\n", ch->limit, name);
 	}