Merge branch 'master' into issue/36307

Author: tebeka

doc/go1.22.html

@@ -83,8 +83,26 @@ <h3 id="vet">Vet</h3>
 
 <h2 id="runtime">Runtime</h2>
 
-<p>
-  TODO: complete this section, or delete if not needed
+<p><!-- CL 543255 -->
+  The runtime now keeps type-based garbage collection metadata nearer to each
+  heap object, improving the CPU performance (latency or throughput) of Go programs
+  by 1&mdash;3%.
+  This change also reduces the memory overhead of the majority Go programs by
+  approximately 1% by deduplicating redundant metadata.
+  Some programs may see a smaller improvement because this change adjusts the size
+  class boundaries of the memory allocator, so some objects may be moved up a size
+  class.
+  <br />
+  A consequence of this change is that some objects' addresses that were previously
+  always aligned to a 16 byte (or higher) boundary will now only be aligned to an 8
+  byte boundary.
+  Some programs that use assembly instructions that require memory addresses to be
+  more than 8-byte aligned and rely on the memory allocator's previous alignment behavior
+  may break, but we expect such programs to be rare.
+  Such programs may be built with <code>GOEXPERIMENT=noallocheaders</code> to revert
+  to the old metadata layout and restore the previous alignment behavior, but package
+  owners should update their assembly code to avoid the alignment assumption, as this
+  workaround will be removed in a future release.
 </p>
 
 <h2 id="compiler">Compiler</h2>
@@ -108,6 +126,14 @@ <h2 id="linker">Linker</h2>
   TODO: complete this section, or delete if not needed
 </p>
 
+<h2 id="bootstrap">Bootstrap</h2>
+
+<p>
+  As mentioned in the <a href="/doc/go1.20#bootstrap">Go 1.20 release notes</a>, Go 1.22 now requires
+  the final point release of Go 1.20 or later for bootstrap.
+  We expect that Go 1.24 will require the final point release of Go 1.22 or later for bootstrap.
+</p>
+
 <h2 id="library">Core library</h2>
 
 <h3 id="minor_library_changes">New math/rand/v2 package</h3>
@@ -294,14 +320,6 @@ <h3 id="minor_library_changes">Minor changes to the library</h3>
   </dd>
 </dl><!-- encoding -->
 
-<dl id="encoding/binary"><dt><a href="/pkg/encoding/binary/">encoding/binary</a></dt>
-  <dd>
-    <p><!-- https://go.dev/issue/57237 -->
-      TODO: <a href="https://go.dev/issue/57237">https://go.dev/issue/57237</a>: add var NativeEndian; also x/sys/cpu.IsBigEndian
-    </p>
-  </dd>
-</dl><!-- encoding/binary -->
-
 <dl id="go/ast"><dt><a href="/pkg/go/ast/">go/ast</a></dt>
   <dd>
     <p><!-- https://go.dev/issue/52463 -->
@@ -486,6 +504,18 @@ <h3 id="minor_library_changes">Minor changes to the library</h3>
   </dd>
 </dl><!-- os/exec -->
 
+<dl id="go/types"><dt><a href="/pkg/go/types/">go/types</a></dt>
+  <dd>
+    <p><!-- https://go.dev/issue/64295, CL 544035 -->
+      The start position (<a href="/pkg/go/types#Scope.Pos">Pos</a>)
+      of the lexical environment block (<a href="/pkg/go/types#Scope">Scope</a>)
+      that represents a function body has changed:
+      it used to start at the opening curly brace of the function body,
+      but now starts at the function's <code>func</code> token.
+    </p>
+  </dd>
+</dl>
+
 <dl id="reflect"><dt><a href="/pkg/reflect/">reflect</a></dt>
   <dd>
     <p><!-- https://go.dev/issue/61827, CL 517777 -->
@@ -505,10 +535,6 @@ <h3 id="minor_library_changes">Minor changes to the library</h3>
     <p><!-- https://go.dev/issue/61015 -->
       TODO: <a href="https://go.dev/issue/61015">https://go.dev/issue/61015</a>: change mutex profile to scale contention by number of blocked goroutines
     </p>
-
-    <p><!-- CL 543255 -->
-      TODO: <a href="https://go.dev/cl/543255">https://go.dev/cl/543255</a>: runtime: put allocation headers back at the start the object
-    </p>
   </dd>
 </dl><!-- runtime -->
 
@@ -522,20 +548,16 @@ <h3 id="minor_library_changes">Minor changes to the library</h3>
 
 <dl id="slices"><dt><a href="/pkg/slices/">slices</a></dt>
   <dd>
-    <p><!-- https://go.dev/issue/56353 -->
-      TODO: <a href="https://go.dev/issue/56353">https://go.dev/issue/56353</a>: add Concat
-    </p>
-
-    <p><!-- https://go.dev/issue/63393 -->
-      TODO: <a href="https://go.dev/issue/63393">https://go.dev/issue/63393</a>: have Delete and others clear the tail
+    <p><!-- https://go.dev/issue/56353 --><!-- CL 504882 -->
+      The new function <code>Concat</code> concatenates multiple slices.
     </p>
 
-    <p><!-- CL 504882 -->
-      TODO: <a href="https://go.dev/cl/504882">https://go.dev/cl/504882</a>: slices: add Concat
+    <p><!-- https://go.dev/issue/63393 --><!-- CL 543335 -->
+      Functions that shrink the size of a slice (<code>Delete</code>, <code>DeleteFunc</code>, <code>Compact</code>, <code>CompactFunc</code>, and <code>Replace</code>) now zero the elements between the new length and the old length.
     </p>
 
-    <p><!-- CL 540155 -->
-      TODO: <a href="https://go.dev/cl/540155">https://go.dev/cl/540155</a>: slices: make Insert panic if index is out of range and there are no values
+    <p><!-- https://go.dev/issue/63913 --><!-- CL 540155 -->
+      <code>Insert</code> now always panics if the argument <code>i</code> is out of range. Previously it did not panic in this situation if there were no elements to be inserted.
     </p>
   </dd>
 </dl><!-- slices -->
@@ -570,8 +592,15 @@ <h3 id="minor_library_changes">Minor changes to the library</h3>
 
 <h2 id="ports">Ports</h2>
 
+<h3 id="arm">Arm</h3>
 <p><!-- CL 514907 -->
-  TODO: <a href="https://go.dev/cl/514907">https://go.dev/cl/514907</a>: all: add floating point option for ARM targets
+  The <code>GOARM</code> environment variable now allows you to select whether to use software or hardware floating point.
+  Previously, valid <code>GOARM</code> values were <code>5</code>, <code>6</code>, or <code>7</code>. Now those same values can
+  be optionally followed by <code>,softfloat</code> or <code>,hardfloat</code> to select the floating-point implementation.
+</p>
+<p>
+  This new option defaults to <code>softfloat</code> for version <code>5</code> and <code>hardfloat</code> for versions
+  <code>6</code> and <code>7</code>.
 </p>
 
 <p><!-- CL 481315 -->

src/bytes/boundary_test.go

@@ -98,3 +98,18 @@ func TestIndexNearPageBoundary(t *testing.T) {
 	}
 	q[len(q)-1] = 0
 }
+
+func TestCountNearPageBoundary(t *testing.T) {
+	t.Parallel()
+	b := dangerousSlice(t)
+	for i := range b {
+		c := Count(b[i:], []byte{1})
+		if c != 0 {
+			t.Fatalf("Count(b[%d:], {1})=%d, want 0\n", i, c)
+		}
+		c = Count(b[:i], []byte{0})
+		if c != i {
+			t.Fatalf("Count(b[:%d], {0})=%d, want %d\n", i, c, i)
+		}
+	}
+}

src/cmd/cgo/internal/test/callback_windows.go

@@ -29,7 +29,7 @@ USHORT backtrace(ULONG FramesToCapture, PVOID *BackTrace) {
 		}
 
 		ControlPc = context.Rip;
-        // Check if we left the user range.
+		// Check if we left the user range.
 		if (ControlPc < 0x10000) {
 			break;
 		}
@@ -65,32 +65,17 @@ func testCallbackCallersSEH(t *testing.T) {
 		// TODO: support SEH on other architectures.
 		t.Skip("skipping on non-amd64")
 	}
-	const cgoexpPrefix = "_cgoexp_"
+	// Only frames in the test package are checked.
 	want := []string{
-		"runtime.asmcgocall_landingpad",
-		"runtime.asmcgocall",
-		"runtime.cgocall",
 		"test._Cfunc_backtrace",
 		"test.testCallbackCallersSEH.func1.1",
 		"test.testCallbackCallersSEH.func1",
 		"test.goCallback",
-		cgoexpPrefix + "goCallback",
-		"runtime.cgocallbackg1",
-		"runtime.cgocallbackg",
-		"runtime.cgocallbackg",
-		"runtime.cgocallback",
-		"crosscall2",
-		"runtime.asmcgocall_landingpad",
-		"runtime.asmcgocall",
-		"runtime.cgocall",
 		"test._Cfunc_callback",
 		"test.nestedCall.func1",
 		"test.nestedCall",
 		"test.testCallbackCallersSEH",
 		"test.TestCallbackCallersSEH",
-		"testing.tRunner",
-		"testing.(*T).Run.gowrap1",
-		"runtime.goexit",
 	}
 	pc := make([]uintptr, 100)
 	n := 0
@@ -105,26 +90,17 @@ func testCallbackCallersSEH(t *testing.T) {
 		}
 		fname := f.Name()
 		switch fname {
-		case "goCallback", "callback":
-			// TODO(qmuntal): investigate why these functions don't appear
+		case "goCallback":
+			// TODO(qmuntal): investigate why this function doesn't appear
 			// when using the external linker.
 			continue
 		}
-		// Skip cgo-generated functions, the runtime might not know about them,
-		// depending on the link mode.
-		if strings.HasPrefix(fname, "_cgo_") {
-			continue
-		}
-		// Remove the cgo-generated random prefix.
-		if strings.HasPrefix(fname, cgoexpPrefix) {
-			idx := strings.Index(fname[len(cgoexpPrefix):], "_")
-			if idx >= 0 {
-				fname = cgoexpPrefix + fname[len(cgoexpPrefix)+idx+1:]
-			}
-		}
 		// In module mode, this package has a fully-qualified import path.
 		// Remove it if present.
 		fname = strings.TrimPrefix(fname, "cmd/cgo/internal/")
+		if !strings.HasPrefix(fname, "test.") {
+			continue
+		}
 		got = append(got, fname)
 	}
 	if !reflect.DeepEqual(want, got) {

src/cmd/compile/internal/noder/helpers.go

@@ -99,6 +99,8 @@ func idealType(tv syntax.TypeAndValue) types2.Type {
 			typ = types2.Typ[types2.Bool] // expression in "if" or "for" condition
 		case types2.UntypedString:
 			typ = types2.Typ[types2.String] // argument to "append" or "copy" calls
+		case types2.UntypedRune:
+			typ = types2.Typ[types2.Int32] // range over rune
 		default:
 			return nil
 		}