Merge branch 'golang:master' into master

cxbdasheng · web-flow · commit e7a4789dcd2b · 2025-07-24T14:11:37.000+08:00
diff --git a/doc/next/1-intro.md b/doc/next/1-intro.md
@@ -0,0 +1,8 @@
+<style>
+  main ul li { margin: 0.5em 0; }
+</style>
+
+## DRAFT RELEASE NOTES — Introduction to Go 1.26 {#introduction}
+
+**Go 1.26 is not yet released. These are work-in-progress release notes.
+Go 1.26 is expected to be released in February 2026.**
diff --git a/doc/next/2-language.md b/doc/next/2-language.md
@@ -0,0 +1,3 @@
+## Changes to the language {#language}
+
+
diff --git a/doc/next/3-tools.md b/doc/next/3-tools.md
@@ -0,0 +1,6 @@
+## Tools {#tools}
+
+### Go command {#go-command}
+
+### Cgo {#cgo}
+
diff --git a/doc/next/4-runtime.md b/doc/next/4-runtime.md
@@ -0,0 +1 @@
+## Runtime {#runtime}
diff --git a/doc/next/5-toolchain.md b/doc/next/5-toolchain.md
@@ -0,0 +1,7 @@
+## Compiler {#compiler}
+
+## Assembler {#assembler}
+
+## Linker {#linker}
+
+
diff --git a/doc/next/6-stdlib/0-heading.md b/doc/next/6-stdlib/0-heading.md
@@ -0,0 +1,2 @@
+## Standard library {#library}
+
diff --git a/doc/next/6-stdlib/99-minor/0-heading.md b/doc/next/6-stdlib/99-minor/0-heading.md
@@ -0,0 +1,10 @@
+### Minor changes to the library {#minor_library_changes}
+
+#### go/types
+
+The `Var.Kind` method returns an enumeration of type `VarKind` that
+classifies the variable (package-level, local, receiver, parameter,
+result, or struct field). See issue #70250.
+
+Callers of `NewVar` or `NewParam` are encouraged to call `Var.SetKind`
+to ensure that this attribute is set correctly in all cases.
diff --git a/doc/next/6-stdlib/99-minor/README b/doc/next/6-stdlib/99-minor/README
@@ -0,0 +1 @@
+API changes and other small changes to the standard library go here.
diff --git a/doc/next/7-ports.md b/doc/next/7-ports.md
@@ -0,0 +1,2 @@
+## Ports {#ports}
+
diff --git a/src/cmd/compile/internal/dwarfgen/dwarf.go b/src/cmd/compile/internal/dwarfgen/dwarf.go
@@ -248,11 +248,6 @@ func createDwarfVars(fnsym *obj.LSym, complexOK bool, fn *ir.Func, apDecls []*ir
 		if n.Class == ir.PPARAM || n.Class == ir.PPARAMOUT {
 			tag = dwarf.DW_TAG_formal_parameter
 		}
-		if n.Esc() == ir.EscHeap {
-			// The variable in question has been promoted to the heap.
-			// Its address is in n.Heapaddr.
-			// TODO(thanm): generate a better location expression
-		}
 		inlIndex := 0
 		if base.Flag.GenDwarfInl > 1 {
 			if n.InlFormal() || n.InlLocal() {
@@ -263,7 +258,7 @@ func createDwarfVars(fnsym *obj.LSym, complexOK bool, fn *ir.Func, apDecls []*ir
 			}
 		}
 		declpos := base.Ctxt.InnermostPos(n.Pos())
-		vars = append(vars, &dwarf.Var{
+		dvar := &dwarf.Var{
 			Name:          n.Sym().Name,
 			IsReturnValue: isReturnValue,
 			Tag:           tag,
@@ -277,8 +272,19 @@ func createDwarfVars(fnsym *obj.LSym, complexOK bool, fn *ir.Func, apDecls []*ir
 			ChildIndex:    -1,
 			DictIndex:     n.DictIndex,
 			ClosureOffset: closureOffset(n, closureVars),
-		})
-		// Record go type of to insure that it gets emitted by the linker.
+		}
+		if n.Esc() == ir.EscHeap {
+			if n.Heapaddr == nil {
+				base.Fatalf("invalid heap allocated var without Heapaddr")
+			}
+			debug := fn.DebugInfo.(*ssa.FuncDebug)
+			list := createHeapDerefLocationList(n, debug.EntryID)
+			dvar.PutLocationList = func(listSym, startPC dwarf.Sym) {
+				debug.PutLocationList(list, base.Ctxt, listSym.(*obj.LSym), startPC.(*obj.LSym))
+			}
+		}
+		vars = append(vars, dvar)
+		// Record go type to ensure that it gets emitted by the linker.
 		fnsym.Func().RecordAutoType(reflectdata.TypeLinksym(n.Type()))
 	}
 
@@ -550,6 +556,29 @@ func createComplexVar(fnsym *obj.LSym, fn *ir.Func, varID ssa.VarID, closureVars
 	return dvar
 }
 
+// createHeapDerefLocationList creates a location list for a heap-escaped variable
+// that describes "dereference pointer at stack offset"
+func createHeapDerefLocationList(n *ir.Name, entryID ssa.ID) []byte {
+	// Get the stack offset where the heap pointer is stored
+	heapPtrOffset := n.Heapaddr.FrameOffset()
+	if base.Ctxt.Arch.FixedFrameSize == 0 {
+		heapPtrOffset -= int64(types.PtrSize)
+	}
+	if buildcfg.FramePointerEnabled {
+		heapPtrOffset -= int64(types.PtrSize)
+	}
+
+	// Create a location expression: DW_OP_fbreg <offset> DW_OP_deref
+	var locExpr []byte
+	var sizeIdx int
+	locExpr, sizeIdx = ssa.SetupLocList(base.Ctxt, entryID, locExpr, ssa.BlockStart.ID, ssa.FuncEnd.ID)
+	locExpr = append(locExpr, dwarf.DW_OP_fbreg)
+	locExpr = dwarf.AppendSleb128(locExpr, heapPtrOffset)
+	locExpr = append(locExpr, dwarf.DW_OP_deref)
+	base.Ctxt.Arch.ByteOrder.PutUint16(locExpr[sizeIdx:], uint16(len(locExpr)-sizeIdx-2))
+	return locExpr
+}
+
 // RecordFlags records the specified command-line flags to be placed
 // in the DWARF info.
 func RecordFlags(flags ...string) {
diff --git a/src/cmd/compile/internal/ssa/debug.go b/src/cmd/compile/internal/ssa/debug.go
@@ -41,6 +41,9 @@ type FuncDebug struct {
 	RegOutputParams []*ir.Name
 	// Variable declarations that were removed during optimization
 	OptDcl []*ir.Name
+	// The ssa.Func.EntryID value, used to build location lists for
+	// return values promoted to heap in later DWARF generation.
+	EntryID ID
 
 	// Filled in by the user. Translates Block and Value ID to PC.
 	//
@@ -1645,13 +1648,13 @@ func readPtr(ctxt *obj.Link, buf []byte) uint64 {
 
 }
 
-// setupLocList creates the initial portion of a location list for a
+// SetupLocList creates the initial portion of a location list for a
 // user variable. It emits the encoded start/end of the range and a
 // placeholder for the size. Return value is the new list plus the
 // slot in the list holding the size (to be updated later).
-func setupLocList(ctxt *obj.Link, f *Func, list []byte, st, en ID) ([]byte, int) {
-	start, startOK := encodeValue(ctxt, f.Entry.ID, st)
-	end, endOK := encodeValue(ctxt, f.Entry.ID, en)
+func SetupLocList(ctxt *obj.Link, entryID ID, list []byte, st, en ID) ([]byte, int) {
+	start, startOK := encodeValue(ctxt, entryID, st)
+	end, endOK := encodeValue(ctxt, entryID, en)
 	if !startOK || !endOK {
 		// This could happen if someone writes a function that uses
 		// >65K values on a 32-bit platform. Hopefully a degraded debugging
@@ -1800,7 +1803,6 @@ func isNamedRegParam(p abi.ABIParamAssignment) bool {
 // appropriate for the ".closureptr" compiler-synthesized variable
 // needed by the debugger for range func bodies.
 func BuildFuncDebugNoOptimized(ctxt *obj.Link, f *Func, loggingEnabled bool, stackOffset func(LocalSlot) int32, rval *FuncDebug) {
-
 	needCloCtx := f.CloSlot != nil
 	pri := f.ABISelf.ABIAnalyzeFuncType(f.Type)
 
@@ -1911,7 +1913,7 @@ func BuildFuncDebugNoOptimized(ctxt *obj.Link, f *Func, loggingEnabled bool, sta
 		// Param is arriving in one or more registers. We need a 2-element
 		// location expression for it. First entry in location list
 		// will correspond to lifetime in input registers.
-		list, sizeIdx := setupLocList(ctxt, f, rval.LocationLists[pidx],
+		list, sizeIdx := SetupLocList(ctxt, f.Entry.ID, rval.LocationLists[pidx],
 			BlockStart.ID, afterPrologVal)
 		if list == nil {
 			pidx++
@@ -1961,7 +1963,7 @@ func BuildFuncDebugNoOptimized(ctxt *obj.Link, f *Func, loggingEnabled bool, sta
 
 		// Second entry in the location list will be the stack home
 		// of the param, once it has been spilled.  Emit that now.
-		list, sizeIdx = setupLocList(ctxt, f, list,
+		list, sizeIdx = SetupLocList(ctxt, f.Entry.ID, list,
 			afterPrologVal, FuncEnd.ID)
 		if list == nil {
 			pidx++
diff --git a/src/cmd/compile/internal/ssagen/ssa.go b/src/cmd/compile/internal/ssagen/ssa.go
@@ -6960,6 +6960,9 @@ func genssa(f *ssa.Func, pp *objw.Progs) {
 	if base.Ctxt.Flag_locationlists {
 		var debugInfo *ssa.FuncDebug
 		debugInfo = e.curfn.DebugInfo.(*ssa.FuncDebug)
+		// Save off entry ID in case we need it later for DWARF generation
+		// for return values promoted to the heap.
+		debugInfo.EntryID = f.Entry.ID
 		if e.curfn.ABI == obj.ABIInternal && base.Flag.N != 0 {
 			ssa.BuildFuncDebugNoOptimized(base.Ctxt, f, base.Debug.LocationLists > 1, StackOffset, debugInfo)
 		} else {
diff --git a/src/cmd/go/internal/base/base.go b/src/cmd/go/internal/base/base.go
@@ -62,11 +62,11 @@ var Go = &Command{
 // Lookup returns the subcommand with the given name, if any.
 // Otherwise it returns nil.
 //
-// Lookup ignores subcommands that have len(c.Commands) == 0 and c.Run == nil.
+// Lookup ignores any subcommand `sub` that has len(sub.Commands) == 0 and sub.Run == nil.
 // Such subcommands are only for use as arguments to "help".
 func (c *Command) Lookup(name string) *Command {
 	for _, sub := range c.Commands {
-		if sub.Name() == name && (len(c.Commands) > 0 || c.Runnable()) {
+		if sub.Name() == name && (len(sub.Commands) > 0 || sub.Runnable()) {
 			return sub
 		}
 	}
diff --git a/src/cmd/internal/obj/arm64/obj7.go b/src/cmd/internal/obj/arm64/obj7.go
@@ -907,18 +907,49 @@ func preprocess(ctxt *obj.Link, cursym *obj.LSym, newprog obj.ProgAlloc) {
 				p.To.Reg = REGFP
 				p.To.Offset = REGLINK
 
-				// ADD $aoffset, RSP, RSP
-				q = newprog()
-				q.As = AADD
-				q.From.Type = obj.TYPE_CONST
-				q.From.Offset = int64(aoffset)
-				q.To.Type = obj.TYPE_REG
-				q.To.Reg = REGSP
-				q.Spadj = -aoffset
-				q.Pos = p.Pos
-				q.Link = p.Link
-				p.Link = q
-				p = q
+				if aoffset < 1<<12 {
+					// ADD $aoffset, RSP, RSP
+					q = newprog()
+					q.As = AADD
+					q.From.Type = obj.TYPE_CONST
+					q.From.Offset = int64(aoffset)
+					q.To.Type = obj.TYPE_REG
+					q.To.Reg = REGSP
+					q.Spadj = -aoffset
+					q.Pos = p.Pos
+					q.Link = p.Link
+					p.Link = q
+					p = q
+				} else {
+					// Put frame size in a separate register and
+					// add it in with a single instruction,
+					// so we never have a partial frame during
+					// the epilog. See issue 73259.
+
+					// MOVD $aoffset, REGTMP
+					q = newprog()
+					q.As = AMOVD
+					q.From.Type = obj.TYPE_CONST
+					q.From.Offset = int64(aoffset)
+					q.To.Type = obj.TYPE_REG
+					q.To.Reg = REGTMP
+					q.Pos = p.Pos
+					q.Link = p.Link
+					p.Link = q
+					p = q
+					// ADD REGTMP, RSP, RSP
+					q = newprog()
+					q.As = AADD
+					q.From.Type = obj.TYPE_REG
+					q.From.Reg = REGTMP
+					q.To.Type = obj.TYPE_REG
+					q.To.Reg = REGSP
+					q.Spadj = -aoffset
+					q.Pos = p.Pos
+					q.Link = p.Link
+					p.Link = q
+					p = q
+				}
 			}
 
 			// If enabled, this code emits 'MOV PC, R27' before every 'MOV LR, PC',
diff --git a/src/cmd/internal/objabi/reloctype.go b/src/cmd/internal/objabi/reloctype.go
@@ -466,7 +466,7 @@ func (r RelocType) IsDwTxtAddr() bool {
 // FuncCountToDwTxtAddrFlavor returns the correct DWARF .debug_addr
 // section relocation to use when compiling a package with a total of
 // fncount functions, along with the size of the ULEB128-encoded blob
-// needed to store the the eventual .debug_addr index.
+// needed to store the eventual .debug_addr index.
 func FuncCountToDwTxtAddrFlavor(fncount int) (RelocType, int) {
 	switch {
 	case fncount <= 127:
diff --git a/src/cmd/link/dwarf_test.go b/src/cmd/link/dwarf_test.go
@@ -256,3 +256,105 @@ func TestDWARFiOS(t *testing.T) {
 		testDWARF(t, "c-archive", true, cc, "CGO_ENABLED=1", "GOOS=ios", "GOARCH=arm64")
 	})
 }
+
+// This test ensures that variables promoted to the heap, specifically
+// function return parameters, have correct location lists generated.
+//
+// TODO(deparker): This test is intentionally limited to GOOS=="linux"
+// and scoped to net.sendFile, which was the function reported originally in
+// issue #65405. There is relevant discussion in https://go-review.googlesource.com/c/go/+/684377
+// pertaining to these limitations. There are other missing location lists which must be fixed
+// particularly in functions where `linkname` is involved.
+func TestDWARFLocationList(t *testing.T) {
+	if runtime.GOOS != "linux" {
+		t.Skip("skipping test on non-linux OS")
+	}
+	testenv.MustHaveCGO(t)
+	testenv.MustHaveGoBuild(t)
+
+	if !platform.ExecutableHasDWARF(runtime.GOOS, runtime.GOARCH) {
+		t.Skipf("skipping on %s/%s: no DWARF symbol table in executables", runtime.GOOS, runtime.GOARCH)
+	}
+
+	t.Parallel()
+
+	tmpDir := t.TempDir()
+	exe := filepath.Join(tmpDir, "issue65405.exe")
+	dir := "./testdata/dwarf/issue65405"
+
+	cmd := testenv.Command(t, testenv.GoToolPath(t), "build", "-toolexec", os.Args[0], "-gcflags=all=-N -l", "-o", exe, dir)
+	cmd.Env = append(os.Environ(), "CGO_CFLAGS=")
+	cmd.Env = append(cmd.Env, "LINK_TEST_TOOLEXEC=1")
+	out, err := cmd.CombinedOutput()
+	if err != nil {
+		t.Fatalf("go build -o %v %v: %v\n%s", exe, dir, err, out)
+	}
+
+	f, err := objfile.Open(exe)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer f.Close()
+
+	d, err := f.DWARF()
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	// Find the net.sendFile function and check its return parameter location list
+	reader := d.Reader()
+
+	for {
+		entry, err := reader.Next()
+		if err != nil {
+			t.Fatal(err)
+		}
+		if entry == nil {
+			break
+		}
+
+		// Look for the net.sendFile subprogram
+		if entry.Tag == dwarf.TagSubprogram {
+			fnName, ok := entry.Val(dwarf.AttrName).(string)
+			if !ok || fnName != "net.sendFile" {
+				reader.SkipChildren()
+				continue
+			}
+
+			for {
+				paramEntry, err := reader.Next()
+				if err != nil {
+					t.Fatal(err)
+				}
+				if paramEntry == nil || paramEntry.Tag == 0 {
+					break
+				}
+
+				if paramEntry.Tag == dwarf.TagFormalParameter {
+					paramName, _ := paramEntry.Val(dwarf.AttrName).(string)
+
+					// Check if this parameter has a location attribute
+					if loc := paramEntry.Val(dwarf.AttrLocation); loc != nil {
+						switch locData := loc.(type) {
+						case []byte:
+							if len(locData) == 0 {
+								t.Errorf("%s return parameter %q has empty location list", fnName, paramName)
+								return
+							}
+						case int64:
+							// Location list offset - this means it has a location list
+							if locData == 0 {
+								t.Errorf("%s return parameter %q has zero location list offset", fnName, paramName)
+								return
+							}
+						default:
+							t.Errorf("%s return parameter %q has unexpected location type %T: %v", fnName, paramName, locData, locData)
+						}
+					} else {
+						t.Errorf("%s return parameter %q has no location attribute", fnName, paramName)
+					}
+				}
+			}
+		}
+	}
+}
diff --git a/src/cmd/link/testdata/dwarf/issue65405/main.go b/src/cmd/link/testdata/dwarf/issue65405/main.go
@@ -0,0 +1,8 @@
+package main
+
+import "net/http"
+
+func main() {
+	http.Handle("/", http.StripPrefix("/static/", http.FileServer(http.Dir("./output"))))
+	http.ListenAndServe(":8000", nil)
+}
diff --git a/src/internal/cgrouptest/cgrouptest_linux.go b/src/internal/cgrouptest/cgrouptest_linux.go
@@ -114,7 +114,7 @@ func findCurrent(t *testing.T) (string, string) {
 	if ver != cgroup.V2 {
 		t.Skipf("cgroup: running on cgroup v%d want v2", ver)
 	}
-	rel := string(buf[1:n]) // The returned path always starts with /, skip it.
+	rel := string(buf[1:n])       // The returned path always starts with /, skip it.
 	rel = filepath.Join(".", rel) // Make sure this isn't empty string at root.
 	return mount, rel
 }
diff --git a/src/internal/goversion/goversion.go b/src/internal/goversion/goversion.go
diff --git a/src/internal/runtime/strconv/atoi.go b/src/internal/runtime/strconv/atoi.go
diff --git a/src/internal/runtime/strconv/atoi_test.go b/src/internal/runtime/strconv/atoi_test.go
diff --git a/src/net/dial.go b/src/net/dial.go
diff --git a/src/runtime/asan_riscv64.s b/src/runtime/asan_riscv64.s
diff --git a/src/runtime/debug.go b/src/runtime/debug.go
diff --git a/src/runtime/testdata/testprog/gc.go b/src/runtime/testdata/testprog/gc.go
diff --git a/src/runtime/vdso_test.go b/src/runtime/vdso_test.go
diff --git a/src/unicode/utf8/utf8.go b/src/unicode/utf8/utf8.go

Original file line number	Diff line number	Diff line change
`@@ -0,0 +1,3 @@`
	`1`	`+## Changes to the language {#language}`
	`2`	`+`
	`3`	`+`
Original file line number	Diff line number	Diff line change
`@@ -0,0 +1 @@`
	`1`	`+API changes and other small changes to the standard library go here.`