cmd/compile: fix panic-okay-to-inline change; adjust tests

This line of the inlining tuning experiment
https://go-review.googlesource.com/c/go/+/109918/1/src/cmd/compile/internal/gc/inl.go#347
was incorrectly rewritten in a later patch to use the call
cost, not the panic cost, and thus the inlining of panic
didn't occur when it should.  I discovered this when I
realized that tests should have failed, but didn't.

Fix is to make the correct change, and also to modify the
tests that this causes to fail.  One test now asserts the
new normal, the other calls "ppanic" instead which is
designed to behave like panic but not be inlined.

Change-Id: I423bb7f08bd66a70d999826dd9b87027abf34cdf
Reviewed-on: https://go-review.googlesource.com/116656
Run-TryBot: David Chase <drchase@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>

src/cmd/compile/internal/gc/inl.go

@@ -352,7 +352,7 @@ func (v *hairyVisitor) visit(n *Node) bool {
 		v.budget -= v.extraCallCost
 
 	case OPANIC:
-		v.budget -= v.extraCallCost
+		v.budget -= inlineExtraPanicCost
 
 	case ORECOVER:
 		// recover matches the argument frame pointer to find

src/runtime/runtime-gdb_test.go

@@ -538,7 +538,7 @@ func TestGdbPanic(t *testing.T) {
 		`main`,
 	}
 	for _, name := range bt {
-		s := fmt.Sprintf("#.* .* in main\\.%v", name)
+		s := fmt.Sprintf("(#.* .* in )?main\\.%v", name)
 		re := regexp.MustCompile(s)
 		if found := re.Find(got) != nil; !found {
 			t.Errorf("could not find '%v' in backtrace", s)

test/closure3.dir/main.go

@@ -15,12 +15,12 @@ func main() {
 		if x := func() int { // ERROR "can inline main.func1"
 			return 1
 		}(); x != 1 { // ERROR "inlining call to main.func1"
-			panic("x != 1")
+			ppanic("x != 1")
 		}
 		if x := func() int { // ERROR "can inline main.func2" "func literal does not escape"
 			return 1
 		}; x() != 1 { // ERROR "inlining call to main.func2"
-			panic("x() != 1")
+			ppanic("x() != 1")
 		}
 	}
 
@@ -28,12 +28,12 @@ func main() {
 		if y := func(x int) int { // ERROR "can inline main.func3"
 			return x + 2
 		}(40); y != 42 { // ERROR "inlining call to main.func3"
-			panic("y != 42")
+			ppanic("y != 42")
 		}
 		if y := func(x int) int { // ERROR "can inline main.func4" "func literal does not escape"
 			return x + 2
 		}; y(40) != 42 { // ERROR "inlining call to main.func4"
-			panic("y(40) != 42")
+			ppanic("y(40) != 42")
 		}
 	}
 
@@ -45,7 +45,7 @@ func main() {
 			return x + 1
 		}
 		if y(40) != 41 {
-			panic("y(40) != 41")
+			ppanic("y(40) != 41")
 		}
 	}
 
@@ -58,7 +58,7 @@ func main() {
 				return x + 1
 			}
 			if y(40) != 41 {
-				panic("y(40) != 41")
+				ppanic("y(40) != 41")
 			}
 		}()
 	}
@@ -71,7 +71,7 @@ func main() {
 			return x + 1
 		}, 42
 		if y(40) != 41 {
-			panic("y(40) != 41")
+			ppanic("y(40) != 41")
 		}
 	}
 
@@ -84,7 +84,7 @@ func main() {
 				return x + 1
 			}, 42
 			if y(40) != 41 {
-				panic("y(40) != 41")
+				ppanic("y(40) != 41")
 			}
 		}()
 	}
@@ -93,13 +93,13 @@ func main() {
 		y := func(x int) int { // ERROR "can inline main.func11" "func literal does not escape"
 			return x + 2
 		}
-		y, sink = func() (func(int)int, int) { // ERROR "func literal does not escape"
+		y, sink = func() (func(int) int, int) { // ERROR "func literal does not escape"
 			return func(x int) int { // ERROR "can inline main.func12" "func literal escapes"
 				return x + 1
 			}, 42
 		}()
 		if y(40) != 41 {
-			panic("y(40) != 41")
+			ppanic("y(40) != 41")
 		}
 	}
 
@@ -114,7 +114,7 @@ func main() {
 				}, 42
 			}()
 			if y(40) != 41 {
-				panic("y(40) != 41")
+				ppanic("y(40) != 41")
 			}
 		}()
 	}
@@ -123,11 +123,11 @@ func main() {
 		y := func(x int) int { // ERROR "can inline main.func14" "func literal does not escape"
 			return x + 2
 		}
-		y, ok = map[int]func(int)int { // ERROR "does not escape"
-			0: func (x int) int { return x + 1 }, // ERROR "can inline main.func15" "func literal escapes"
+		y, ok = map[int]func(int) int{ // ERROR "does not escape"
+			0: func(x int) int { return x + 1 }, // ERROR "can inline main.func15" "func literal escapes"
 		}[0]
 		if y(40) != 41 {
-			panic("y(40) != 41")
+			ppanic("y(40) != 41")
 		}
 	}
 
@@ -136,11 +136,11 @@ func main() {
 			y := func(x int) int { // ERROR "can inline main.func16.1" "func literal does not escape"
 				return x + 2
 			}
-			y, ok = map[int]func(int) int{// ERROR "does not escape"
+			y, ok = map[int]func(int) int{ // ERROR "does not escape"
 				0: func(x int) int { return x + 1 }, // ERROR "can inline main.func16.2" "func literal escapes"
 			}[0]
 			if y(40) != 41 {
-				panic("y(40) != 41")
+				ppanic("y(40) != 41")
 			}
 		}()
 	}
@@ -149,11 +149,11 @@ func main() {
 		y := func(x int) int { // ERROR "can inline main.func17" "func literal does not escape"
 			return x + 2
 		}
-		y, ok = interface{}(func (x int) int { // ERROR "can inline main.func18" "does not escape"
+		y, ok = interface{}(func(x int) int { // ERROR "can inline main.func18" "does not escape"
 			return x + 1
-		}).(func(int)int)
+		}).(func(int) int)
 		if y(40) != 41 {
-			panic("y(40) != 41")
+			ppanic("y(40) != 41")
 		}
 	}
 
@@ -166,7 +166,7 @@ func main() {
 				return x + 1
 			}).(func(int) int)
 			if y(40) != 41 {
-				panic("y(40) != 41")
+				ppanic("y(40) != 41")
 			}
 		}()
 	}
@@ -176,12 +176,12 @@ func main() {
 		if y := func() int { // ERROR "can inline main.func20"
 			return x
 		}(); y != 42 { // ERROR "inlining call to main.func20"
-			panic("y != 42")
+			ppanic("y != 42")
 		}
 		if y := func() int { // ERROR "can inline main.func21" "func literal does not escape"
 			return x
 		}; y() != 42 { // ERROR "inlining call to main.func21"
-			panic("y() != 42")
+			ppanic("y() != 42")
 		}
 	}
 
@@ -192,14 +192,14 @@ func main() {
 				return x + y
 			}() // ERROR "inlining call to main.func22.1"
 		}(1); z != 43 {
-			panic("z != 43")
+			ppanic("z != 43")
 		}
 		if z := func(y int) int { // ERROR "func literal does not escape"
 			return func() int { // ERROR "can inline main.func23.1"
 				return x + y
 			}() // ERROR "inlining call to main.func23.1"
 		}; z(1) != 43 {
-			panic("z(1) != 43")
+			ppanic("z(1) != 43")
 		}
 	}
 
@@ -211,7 +211,7 @@ func main() {
 			}() // ERROR "inlining call to main.func24" "&a does not escape"
 		}()
 		if a != 2 {
-			panic("a != 2")
+			ppanic("a != 2")
 		}
 	}
 
@@ -222,11 +222,11 @@ func main() {
 				b = 3
 			}() // ERROR "inlining call to main.func25.1" "&b does not escape"
 			if b != 3 {
-				panic("b != 3")
+				ppanic("b != 3")
 			}
 		}(b)
 		if b != 2 {
-			panic("b != 2")
+			ppanic("b != 2")
 		}
 	}
 
@@ -236,12 +236,12 @@ func main() {
 			c = 4
 			func() { // ERROR "func literal does not escape"
 				if c != 4 {
-					panic("c != 4")
+					ppanic("c != 4")
 				}
 			}()
 		}()
 		if c != 4 {
-			panic("c != 4")
+			ppanic("c != 4")
 		}
 	}
 
@@ -256,7 +256,7 @@ func main() {
 				}(10) // ERROR "inlining call to main.func27.1.1"
 			}(100)
 		}(1000); r != 2350 {
-			panic("r != 2350")
+			ppanic("r != 2350")
 		}
 	}
 
@@ -274,10 +274,15 @@ func main() {
 				return a + c
 			}(100) + b
 		}(1000); r != 2350 {
-			panic("r != 2350")
+			ppanic("r != 2350")
 		}
 		if a != 2000 {
-			panic("a != 2000")
+			ppanic("a != 2000")
 		}
 	}
 }
+
+//go:noinline
+func ppanic(s string) { // ERROR "leaking param: s"
+	panic(s)
+}

test/escape4.go

@@ -34,8 +34,8 @@ func f1() {
 
 func f2() {} // ERROR "can inline f2"
 
-// No inline for panic, recover.
-func f3() { panic(1) }
+// No inline for recover; panic now allowed to inline.
+func f3() { panic(1) } // ERROR "can inline f3"
 func f4() { recover() }
 
 func f5() *byte {