runtime: enable precise GC checks when using stack maps

    In the runtime there are bad pointer checks that currently don't
    work with the concervative collector. With stack maps, the GC is
    precise and the checks should work. Enable them.

    Reviewed-on: https://go-review.googlesource.com/c/gofrontend/+/153871

From-SVN: r269406

diff --git a/gcc/go/gofrontend/MERGE b/gcc/go/gofrontend/MERGE
index 3315957aea5496f1455d9509e0bc518a8004f4b4..78dd824fc74e536160dbcf0d514a66432afac8c1 100644 (file)
--- a/gcc/go/gofrontend/MERGE
+++ b/gcc/go/gofrontend/MERGE
@@ -1,4 +1,4 @@
-14e48e756af205a68374c872f3bd03d62ccd70bb
+3f8ddaa1d773309b6a4b8e4640f8b9675d9764c6
 
 The first line of this file holds the git revision number of the last
 merge done from the gofrontend repository.

diff --git a/libgo/go/runtime/mgcmark.go b/libgo/go/runtime/mgcmark.go
index 9da881ed2ab85bc09f23640bd24e3b6051a86bd0..dc5e797739ed6ce19ea701e926169dfc689df127 100644 (file)
--- a/libgo/go/runtime/mgcmark.go
+++ b/libgo/go/runtime/mgcmark.go
@@ -1106,9 +1106,9 @@ func scanstackblockwithmap(pc, b0, n0 uintptr, ptrmask *uint8, gcw *gcWork) {
 // Preemption must be disabled.
 //go:nowritebarrier
 func shade(b uintptr) {
-       if obj, span, objIndex := findObject(b, 0, 0, true); obj != 0 {
+       if obj, span, objIndex := findObject(b, 0, 0, !usestackmaps); obj != 0 {
                gcw := &getg().m.p.ptr().gcw
-               greyobject(obj, 0, 0, span, gcw, objIndex, true)
+               greyobject(obj, 0, 0, span, gcw, objIndex, !usestackmaps)
        }
 }
 

diff --git a/libgo/go/runtime/mgcsweep.go b/libgo/go/runtime/mgcsweep.go
index fb5ee6ad46d788c036458bf5a86d934f6f57b604..bc53de44e666a0b2488fdaade4b11d11afbfcccd 100644 (file)
--- a/libgo/go/runtime/mgcsweep.go
+++ b/libgo/go/runtime/mgcsweep.go
@@ -342,8 +342,10 @@ func (s *mspan) sweep(preserve bool) bool {
        // it is not otherwise a problem. So we disable the test for gccgo.
        nfreedSigned := int(nfreed)
        if nalloc > s.allocCount {
-               // print("runtime: nelems=", s.nelems, " nalloc=", nalloc, " previous allocCount=", s.allocCount, " nfreed=", nfreed, "\n")
-               // throw("sweep increased allocation count")
+               if usestackmaps {
+                       print("runtime: nelems=", s.nelems, " nalloc=", nalloc, " previous allocCount=", s.allocCount, " nfreed=", nfreed, "\n")
+                       throw("sweep increased allocation count")
+               }
 
                // For gccgo, adjust the freed count as a signed number.
                nfreedSigned = int(s.allocCount) - int(nalloc)

diff --git a/libgo/go/runtime/runtime1.go b/libgo/go/runtime/runtime1.go
index 66091ff65808c14960f668c2948f24a77e2ac7b4..e2567b35a3f68b48d24226ac4ff5cf5321d440ad 100644 (file)
--- a/libgo/go/runtime/runtime1.go
+++ b/libgo/go/runtime/runtime1.go
@@ -362,7 +362,9 @@ func parsedebugvars() {
        // At that point, if debug.invalidptr is set, we crash.
        // This is not a problem, assuming that M1 really is dead and
        // the pointer we discovered to it will not be used.
-       // debug.invalidptr = 1
+       if usestackmaps {
+               debug.invalidptr = 1
+       }
 
        for p := gogetenv("GODEBUG"); p != ""; {
                field := ""