proc: bugs setting next breakpoints

1. A running goroutine is by definition not parked waiting for a
chan recv
2. The FDE end address is intended to be exclusive, the code
interpreted as inclusive and sometimes ended up setting a breakpoint
on a function other than the current one.

_fixtures/issue332.go

@@ -0,0 +1,15 @@
+package main
+
+import "fmt"
+
+func main() {
+	m := make([]string, 1, 25)
+	fmt.Println(m) // [ ]
+	changeMe(m)
+	fmt.Println(m) // [Todd]
+}
+
+func changeMe(z []string) {
+	z[0] = "Todd"
+	fmt.Println(z) // [Todd]
+}

proc/proc_test.go

@@ -19,6 +19,8 @@ import (
 	protest "github.com/derekparker/delve/proc/test"
 )
 
+const disableFailingTests = true
+
 func init() {
 	runtime.GOMAXPROCS(4)
 	os.Setenv("GOMAXPROCS", "4")
@@ -1475,3 +1477,65 @@ func TestIssue384(t *testing.T) {
 		assertNoError(err, t, "EvalVariable()")
 	})
 }
+
+func TestIssue332_Part1(t *testing.T) {
+	// Next shouldn't step inside a function call
+	withTestProcess("issue332", t, func(p *Process, fixture protest.Fixture) {
+		start, _, err := p.goSymTable.LineToPC(fixture.Source, 8)
+		assertNoError(err, t, "LineToPC()")
+		_, err = p.SetBreakpoint(start)
+		assertNoError(err, t, "SetBreakpoint()")
+		assertNoError(p.Continue(), t, "Continue()")
+		assertNoError(p.Next(), t, "first Next()")
+		locations, err := p.CurrentThread.Stacktrace(2)
+		assertNoError(err, t, "Stacktrace()")
+		if locations[0].Call.Fn == nil {
+			t.Fatalf("Not on a function")
+		}
+		if locations[0].Call.Fn.Name != "main.main" {
+			t.Fatalf("Not on main.main after Next: %s (%s:%d)", locations[0].Call.Fn.Name, locations[0].Call.File, locations[0].Call.Line)
+		}
+		if locations[0].Call.Line != 9 {
+			t.Fatalf("Not on line 9 after Next: %s (%s:%d)", locations[0].Call.Fn.Name, locations[0].Call.File, locations[0].Call.Line)
+		}
+	})
+}
+
+func TestIssue332_Part2(t *testing.T) {
+	// Step should skip a function's prologue
+	// In some parts of the prologue, for some functions, the FDE data is incorrect
+	// which leads to 'next' and 'stack' failing with error "could not find FDE for PC: <garbage>"
+	// because the incorrect FDE data leads to reading the wrong stack address as the return address
+	// TODO: the incorrect FDE data problem is fixed in go 1.6, reenable this test when 1.6 is released.
+	if disableFailingTests {
+		return
+	}
+	withTestProcess("issue332", t, func(p *Process, fixture protest.Fixture) {
+		start, _, err := p.goSymTable.LineToPC(fixture.Source, 8)
+		assertNoError(err, t, "LineToPC()")
+		_, err = p.SetBreakpoint(start)
+		assertNoError(err, t, "SetBreakpoint()")
+		assertNoError(p.Continue(), t, "Continue()")
+
+		// step until we enter changeMe
+		for {
+			assertNoError(p.Step(), t, "Step()")
+			locations, err := p.CurrentThread.Stacktrace(2)
+			assertNoError(err, t, "Stacktrace()")
+			if locations[0].Call.Fn == nil {
+				t.Fatalf("Not on a function")
+			}
+			if locations[0].Call.Fn.Name == "main.changeMe" {
+				break
+			}
+		}
+
+		assertNoError(p.Next(), t, "first Next()")
+		assertNoError(p.Next(), t, "second Next()")
+		assertNoError(p.Next(), t, "third Next()")
+		err = p.Continue()
+		if _, exited := err.(ProcessExitedError); !exited {
+			assertNoError(err, t, "final Continue()")
+		}
+	})
+}

proc/threads.go

@@ -164,7 +164,7 @@ func (ge GoroutineExitingError) Error() string {
 // Set breakpoints at every line, and the return address. Also look for
 // a deferred function and set a breakpoint there too.
 func (thread *Thread) next(curpc uint64, fde *frame.FrameDescriptionEntry, file string, line int) error {
-	pcs := thread.dbp.lineInfo.AllPCsBetween(fde.Begin(), fde.End(), file)
+	pcs := thread.dbp.lineInfo.AllPCsBetween(fde.Begin(), fde.End()-1, file)
 
 	g, err := thread.GetG()
 	if err != nil {

proc/variables.go

@@ -311,7 +311,7 @@ func (scope *EvalScope) PtrSize() int {
 // ChanRecvBlocked returns whether the goroutine is blocked on
 // a channel read operation.
 func (g *G) ChanRecvBlocked() bool {
-	return g.WaitReason == chanRecv
+	return (g.thread == nil) && (g.WaitReason == chanRecv)
 }
 
 // chanRecvReturnAddr returns the address of the return from a channel read.

terminal/command.go

@@ -882,7 +882,7 @@ func printcontextThread(t *Term, th *api.Thread) {
 	fn := th.Function
 
 	if th.Breakpoint == nil {
-		fmt.Printf("> %s() %s:%d\n", fn.Name, ShortenFilePath(th.File), th.Line)
+		fmt.Printf("> %s() %s:%d (PC: %#v)\n", fn.Name, ShortenFilePath(th.File), th.Line, th.PC)
 		return
 	}
 
@@ -896,21 +896,23 @@ func printcontextThread(t *Term, th *api.Thread) {
 	}
 
 	if hitCount, ok := th.Breakpoint.HitCount[strconv.Itoa(th.GoroutineID)]; ok {
-		fmt.Printf("> %s(%s) %s:%d (hits goroutine(%d):%d total:%d)\n",
+		fmt.Printf("> %s(%s) %s:%d (hits goroutine(%d):%d total:%d) (PC: %#v)\n",
 			fn.Name,
 			args,
 			ShortenFilePath(th.File),
 			th.Line,
 			th.GoroutineID,
 			hitCount,
-			th.Breakpoint.TotalHitCount)
+			th.Breakpoint.TotalHitCount,
+			th.PC)
 	} else {
-		fmt.Printf("> %s(%s) %s:%d (hits total:%d)\n",
+		fmt.Printf("> %s(%s) %s:%d (hits total:%d) (PC: %#v)\n",
 			fn.Name,
 			args,
 			ShortenFilePath(th.File),
 			th.Line,
-			th.Breakpoint.TotalHitCount)
+			th.Breakpoint.TotalHitCount,
+			th.PC)
 	}
 
 	if th.BreakpointInfo != nil {