1 files changed, 82 insertions, 24 deletions

diff --git a/src/runtime/stack.go b/src/runtime/stack.go
index d971e5e26f..b21c9c9518 100644
--- a/src/runtime/stack.go
+++ b/src/runtime/stack.go
@@ -5,6 +5,7 @@
 package runtime
 
 import (
+	"internal/abi"
 	"internal/cpu"
 	"runtime/internal/atomic"
 	"runtime/internal/sys"
@@ -91,6 +92,10 @@ const (
 
 	// The stack guard is a pointer this many bytes above the
 	// bottom of the stack.
+	//
+	// The guard leaves enough room for one _StackSmall frame plus
+	// a _StackLimit chain of NOSPLIT calls plus _StackSystem
+	// bytes for the OS.
 	_StackGuard = 928*sys.StackGuardMultiplier + _StackSystem
 
 	// After a stack split check the SP is allowed to be this
@@ -122,16 +127,21 @@ const (
 const (
 	uintptrMask = 1<<(8*sys.PtrSize) - 1
 
+	// The values below can be stored to g.stackguard0 to force
+	// the next stack check to fail.
+	// These are all larger than any real SP.
+
 	// Goroutine preemption request.
-	// Stored into g->stackguard0 to cause split stack check failure.
-	// Must be greater than any real sp.
 	// 0xfffffade in hex.
 	stackPreempt = uintptrMask & -1314
 
-	// Thread is forking.
-	// Stored into g->stackguard0 to cause split stack check failure.
-	// Must be greater than any real sp.
+	// Thread is forking. Causes a split stack check failure.
+	// 0xfffffb2e in hex.
 	stackFork = uintptrMask & -1234
+
+	// Force a stack movement. Used for debugging.
+	// 0xfffffeed in hex.
+	stackForceMove = uintptrMask & -275
 )
 
 // Global pool of spans that have free stacks.
@@ -692,15 +702,15 @@ func adjustframe(frame *stkframe, arg unsafe.Pointer) bool {
 				// we call into morestack.)
 				continue
 			}
-			t := obj.typ
-			gcdata := t.gcdata
+			ptrdata := obj.ptrdata()
+			gcdata := obj.gcdata
 			var s *mspan
-			if t.kind&kindGCProg != 0 {
+			if obj.useGCProg() {
 				// See comments in mgcmark.go:scanstack
-				s = materializeGCProg(t.ptrdata, gcdata)
+				s = materializeGCProg(ptrdata, gcdata)
 				gcdata = (*byte)(unsafe.Pointer(s.startAddr))
 			}
-			for i := uintptr(0); i < t.ptrdata; i += sys.PtrSize {
+			for i := uintptr(0); i < ptrdata; i += sys.PtrSize {
 				if *addb(gcdata, i/(8*sys.PtrSize))>>(i/sys.PtrSize&7)&1 != 0 {
 					adjustpointer(adjinfo, unsafe.Pointer(p+i))
 				}
@@ -1054,11 +1064,18 @@ func newstack() {
 	// recheck the bounds on return.)
 	if f := findfunc(gp.sched.pc); f.valid() {
 		max := uintptr(funcMaxSPDelta(f))
-		for newsize-oldsize < max+_StackGuard {
+		for newsize-gp.sched.sp < max+_StackGuard {
 			newsize *= 2
 		}
 	}
 
+	if gp.stackguard0 == stackForceMove {
+		// Forced stack movement used for debugging.
+		// Don't double the stack (or we may quickly run out
+		// if this is done repeatedly).
+		newsize = oldsize
+	}
+
 	if newsize > maxstacksize || newsize > maxstackceiling {
 		if maxstacksize < maxstackceiling {
 			print("runtime: goroutine stack exceeds ", maxstacksize, "-byte limit\n")
@@ -1301,29 +1318,70 @@ func getStackMap(frame *stkframe, cache *pcvalueCache, debug bool) (locals, args
 	}
 
 	// stack objects.
-	p := funcdata(f, _FUNCDATA_StackObjects)
-	if p != nil {
-		n := *(*uintptr)(p)
-		p = add(p, sys.PtrSize)
-		*(*slice)(unsafe.Pointer(&objs)) = slice{array: noescape(p), len: int(n), cap: int(n)}
-		// Note: the noescape above is needed to keep
-		// getStackMap from "leaking param content:
-		// frame".  That leak propagates up to getgcmask, then
-		// GCMask, then verifyGCInfo, which converts the stack
-		// gcinfo tests into heap gcinfo tests :(
+	if GOARCH == "amd64" && unsafe.Sizeof(abi.RegArgs{}) > 0 && frame.argmap != nil {
+		// argmap is set when the function is reflect.makeFuncStub or reflect.methodValueCall.
+		// We don't actually use argmap in this case, but we need to fake the stack object
+		// record for these frames which contain an internal/abi.RegArgs at a hard-coded offset
+		// on amd64.
+		objs = methodValueCallFrameObjs
+	} else {
+		p := funcdata(f, _FUNCDATA_StackObjects)
+		if p != nil {
+			n := *(*uintptr)(p)
+			p = add(p, sys.PtrSize)
+			*(*slice)(unsafe.Pointer(&objs)) = slice{array: noescape(p), len: int(n), cap: int(n)}
+			// Note: the noescape above is needed to keep
+			// getStackMap from "leaking param content:
+			// frame".  That leak propagates up to getgcmask, then
+			// GCMask, then verifyGCInfo, which converts the stack
+			// gcinfo tests into heap gcinfo tests :(
+		}
 	}
 
 	return
 }
 
+var (
+	abiRegArgsEface          interface{} = abi.RegArgs{}
+	abiRegArgsType           *_type      = efaceOf(&abiRegArgsEface)._type
+	methodValueCallFrameObjs             = []stackObjectRecord{
+		{
+			off:      -int32(alignUp(abiRegArgsType.size, 8)), // It's always the highest address local.
+			size:     int32(abiRegArgsType.size),
+			_ptrdata: int32(abiRegArgsType.ptrdata),
+			gcdata:   abiRegArgsType.gcdata,
+		},
+	}
+)
+
+func init() {
+	if abiRegArgsType.kind&kindGCProg != 0 {
+		throw("abiRegArgsType needs GC Prog, update methodValueCallFrameObjs")
+	}
+}
+
 // A stackObjectRecord is generated by the compiler for each stack object in a stack frame.
-// This record must match the generator code in cmd/compile/internal/gc/ssa.go:emitStackObjects.
+// This record must match the generator code in cmd/compile/internal/liveness/plive.go:emitStackObjects.
 type stackObjectRecord struct {
 	// offset in frame
 	// if negative, offset from varp
 	// if non-negative, offset from argp
-	off int
-	typ *_type
+	off      int32
+	size     int32
+	_ptrdata int32 // ptrdata, or -ptrdata is GC prog is used
+	gcdata   *byte // pointer map or GC prog of the type
+}
+
+func (r *stackObjectRecord) useGCProg() bool {
+	return r._ptrdata < 0
+}
+
+func (r *stackObjectRecord) ptrdata() uintptr {
+	x := r._ptrdata
+	if x < 0 {
+		return uintptr(-x)
+	}
+	return uintptr(x)
 }
 
 // This is exported as ABI0 via linkname so obj can call it.