all: merge master (5b5d57c) into gopls-release-branch.0.17

Merge List:

+ 2024-11-14 5b5d57c gopls/codeaction: fix panic when removing unused parameters with syntax errors.
+ 2024-11-13 025b812 gopls/internal/server: don't call window/showDocument if unsupported
+ 2024-11-13 288b9cb gopls/internal/golang: add missing imports in foo_test.go
+ 2024-11-13 87ac91f gopls/internal/server: revert the gopls.run_govulncheck command
+ 2024-11-12 c531f1b gopls/internal/golang: avoid crash in hover on field of non-struct
+ 2024-11-12 a37eeb4 README: mention the git repo
+ 2024-11-12 8dd84a4 go/ssa/interp: assign phi nodes in parallel

For golang/go#70301

Change-Id: I9b584de0bcbd622a6bcf5f06f34232993ac2f9a4

Author: findleyr

README.md

@@ -76,10 +76,12 @@ golang.org/x/tools/txtar
 ## Contributing
 
 This repository uses Gerrit for code changes.
-To learn how to submit changes, see https://golang.org/doc/contribute.html.
+To learn how to submit changes, see https://go.dev/doc/contribute.
+
+The git repository is https://go.googlesource.com/tools.
 
 The main issue tracker for the tools repository is located at
-https://github.com/golang/go/issues. Prefix your issue with "x/tools/(your
+https://go.dev/issues. Prefix your issue with "x/tools/(your
 subdir):" in the subject line, so it is easy to find.
 
 ### JavaScript and CSS Formatting

go/ssa/interp/interp.go

@@ -48,9 +48,11 @@ import (
 	"fmt"
 	"go/token"
 	"go/types"
+	"log"
 	"os"
 	"reflect"
 	"runtime"
+	"slices"
 	"sync/atomic"
 	_ "unsafe"
 
@@ -108,6 +110,7 @@ type frame struct {
 	result           value
 	panicking        bool
 	panic            interface{}
+	phitemps         []value // temporaries for parallel phi assignment
 }
 
 func (fr *frame) get(key ssa.Value) value {
@@ -379,12 +382,7 @@ func visitInstr(fr *frame, instr ssa.Instruction) continuation {
 		fr.env[instr] = &closure{instr.Fn.(*ssa.Function), bindings}
 
 	case *ssa.Phi:
-		for i, pred := range instr.Block().Preds {
-			if fr.prevBlock == pred {
-				fr.env[instr] = fr.get(instr.Edges[i])
-				break
-			}
-		}
+		log.Fatal("unreachable") // phis are processed at block entry
 
 	case *ssa.Select:
 		var cases []reflect.SelectCase
@@ -589,25 +587,57 @@ func runFrame(fr *frame) {
 		if fr.i.mode&EnableTracing != 0 {
 			fmt.Fprintf(os.Stderr, ".%s:\n", fr.block)
 		}
-	block:
-		for _, instr := range fr.block.Instrs {
+
+		nonPhis := executePhis(fr)
+		for _, instr := range nonPhis {
 			if fr.i.mode&EnableTracing != 0 {
 				if v, ok := instr.(ssa.Value); ok {
 					fmt.Fprintln(os.Stderr, "\t", v.Name(), "=", instr)
 				} else {
 					fmt.Fprintln(os.Stderr, "\t", instr)
 				}
 			}
-			switch visitInstr(fr, instr) {
-			case kReturn:
+			if visitInstr(fr, instr) == kReturn {
 				return
-			case kNext:
-				// no-op
-			case kJump:
-				break block
 			}
+			// Inv: kNext (continue) or kJump (last instr)
+		}
+	}
+}
+
+// executePhis executes the phi-nodes at the start of the current
+// block and returns the non-phi instructions.
+func executePhis(fr *frame) []ssa.Instruction {
+	firstNonPhi := -1
+	for i, instr := range fr.block.Instrs {
+		if _, ok := instr.(*ssa.Phi); !ok {
+			firstNonPhi = i
+			break
+		}
+	}
+	// Inv: 0 <= firstNonPhi; every block contains a non-phi.
+
+	nonPhis := fr.block.Instrs[firstNonPhi:]
+	if firstNonPhi > 0 {
+		phis := fr.block.Instrs[:firstNonPhi]
+		// Execute parallel assignment of phis.
+		//
+		// See "the swap problem" in Briggs et al's "Practical Improvements
+		// to the Construction and Destruction of SSA Form" for discussion.
+		predIndex := slices.Index(fr.block.Preds, fr.prevBlock)
+		fr.phitemps = fr.phitemps[:0]
+		for _, phi := range phis {
+			phi := phi.(*ssa.Phi)
+			if fr.i.mode&EnableTracing != 0 {
+				fmt.Fprintln(os.Stderr, "\t", phi.Name(), "=", phi)
+			}
+			fr.phitemps = append(fr.phitemps, fr.get(phi.Edges[predIndex]))
+		}
+		for i, phi := range phis {
+			fr.env[phi.(*ssa.Phi)] = fr.phitemps[i]
 		}
 	}
+	return nonPhis
 }
 
 // doRecover implements the recover() built-in.

go/ssa/interp/interp_test.go

@@ -136,6 +136,7 @@ var testdataTests = []string{
 	"fixedbugs/issue52835.go",
 	"fixedbugs/issue55086.go",
 	"fixedbugs/issue66783.go",
+	"fixedbugs/issue69929.go",
 	"typeassert.go",
 	"zeros.go",
 	"slice2array.go",

go/ssa/interp/testdata/fixedbugs/issue69929.go

@@ -0,0 +1,67 @@
+package main
+
+// This is a regression test for a bug (#69929) in
+// the SSA interpreter in which it would not execute phis in parallel.
+//
+// The insert function below has interdependent phi nodes:
+//
+//	  entry:
+//		t0 = *root       // t0 is x or y before loop
+//		jump test
+//	  body:
+//		print(t5)      // t5 is x at loop entry
+//		t3 = t5.Child    // t3 is x after loop
+//		jump test
+//	  test:
+//		t5 = phi(t0, t3) // t5 is x at loop entry
+//		t6 = phi(t0, t5) // t6 is y at loop entry
+//		if t5 != nil goto body else done
+//	  done:
+//		print(t6)
+//		return
+//
+// The two phis:
+//
+//	t5 = phi(t0, t3)
+//	t6 = phi(t0, t5)
+//
+// must be executed in parallel as if they were written in Go
+// as:
+//
+//	t5, t6 = phi(t0, t3), phi(t0, t5)
+//
+// with the second phi node observing the original, not
+// updated, value of t5. (In more complex examples, the phi
+// nodes may be mutually recursive, breaking partial solutions
+// based on simple reordering of the phi instructions. See the
+// Briggs paper for detail.)
+//
+// The correct behavior is print(1, root); print(2, root); print(3, root).
+// The previous incorrect behavior had print(2, nil).
+
+func main() {
+	insert()
+	print(3, root)
+}
+
+var root = new(node)
+
+type node struct{ child *node }
+
+func insert() {
+	x := root
+	y := x
+	for x != nil {
+		y = x
+		print(1, y)
+		x = x.child
+	}
+	print(2, y)
+}
+
+func print(order int, ptr *node) {
+	println(order, ptr)
+	if ptr != root {
+		panic(ptr)
+	}
+}

gopls/doc/codelenses.md

@@ -97,16 +97,15 @@ Default: off
 
 File type: Go
 
-## `run_govulncheck`: Run govulncheck
+## `run_govulncheck`: Run govulncheck (legacy)
 
 
-This codelens source annotates the `module` directive in a
-go.mod file with a command to run Govulncheck.
+This codelens source annotates the `module` directive in a go.mod file
+with a command to run Govulncheck asynchronously.
 
-[Govulncheck](https://go.dev/blog/vuln) is a static
-analysis tool that computes the set of functions reachable
-within your application, including dependencies;
-queries a database of known security vulnerabilities; and
+[Govulncheck](https://go.dev/blog/vuln) is a static analysis tool that
+computes the set of functions reachable within your application, including
+dependencies; queries a database of known security vulnerabilities; and
 reports any potential problems it finds.
 
 
@@ -157,4 +156,20 @@ Default: on
 
 File type: go.mod
 
+## `vulncheck`: Run govulncheck
+
+
+This codelens source annotates the `module` directive in a go.mod file
+with a command to run govulncheck synchronously.
+
+[Govulncheck](https://go.dev/blog/vuln) is a static analysis tool that
+computes the set of functions reachable within your application, including
+dependencies; queries a database of known security vulnerabilities; and
+reports any potential problems it finds.
+
+
+Default: off
+
+File type: go.mod
+
 <!-- END Lenses: DO NOT MANUALLY EDIT THIS SECTION -->

gopls/go.mod

@@ -26,3 +26,5 @@ require (
 	golang.org/x/exp/typeparams v0.0.0-20231108232855-2478ac86f678 // indirect
 	gopkg.in/check.v1 v1.0.0-20190902080502-41f04d3bba15 // indirect
 )
+
+replace golang.org/x/tools => ../

gopls/internal/doc/api.json

@@ -811,7 +811,7 @@
 						},
 						{
 							"Name": "\"run_govulncheck\"",
-							"Doc": "`\"run_govulncheck\"`: Run govulncheck\n\nThis codelens source annotates the `module` directive in a\ngo.mod file with a command to run Govulncheck.\n\n[Govulncheck](https://go.dev/blog/vuln) is a static\nanalysis tool that computes the set of functions reachable\nwithin your application, including dependencies;\nqueries a database of known security vulnerabilities; and\nreports any potential problems it finds.\n",
+							"Doc": "`\"run_govulncheck\"`: Run govulncheck (legacy)\n\nThis codelens source annotates the `module` directive in a go.mod file\nwith a command to run Govulncheck asynchronously.\n\n[Govulncheck](https://go.dev/blog/vuln) is a static analysis tool that\ncomputes the set of functions reachable within your application, including\ndependencies; queries a database of known security vulnerabilities; and\nreports any potential problems it finds.\n",
 							"Default": "false"
 						},
 						{
@@ -833,6 +833,11 @@
 							"Name": "\"vendor\"",
 							"Doc": "`\"vendor\"`: Update vendor directory\n\nThis codelens source annotates the `module` directive in a\ngo.mod file with a command to run [`go mod\nvendor`](https://go.dev/ref/mod#go-mod-vendor), which\ncreates or updates the directory named `vendor` in the\nmodule root so that it contains an up-to-date copy of all\nnecessary package dependencies.\n",
 							"Default": "true"
+						},
+						{
+							"Name": "\"vulncheck\"",
+							"Doc": "`\"vulncheck\"`: Run govulncheck\n\nThis codelens source annotates the `module` directive in a go.mod file\nwith a command to run govulncheck synchronously.\n\n[Govulncheck](https://go.dev/blog/vuln) is a static analysis tool that\ncomputes the set of functions reachable within your application, including\ndependencies; queries a database of known security vulnerabilities; and\nreports any potential problems it finds.\n",
+							"Default": "false"
 						}
 					]
 				},
@@ -953,8 +958,8 @@
 		{
 			"FileType": "go.mod",
 			"Lens": "run_govulncheck",
-			"Title": "Run govulncheck",
-			"Doc": "\nThis codelens source annotates the `module` directive in a\ngo.mod file with a command to run Govulncheck.\n\n[Govulncheck](https://go.dev/blog/vuln) is a static\nanalysis tool that computes the set of functions reachable\nwithin your application, including dependencies;\nqueries a database of known security vulnerabilities; and\nreports any potential problems it finds.\n",
+			"Title": "Run govulncheck (legacy)",
+			"Doc": "\nThis codelens source annotates the `module` directive in a go.mod file\nwith a command to run Govulncheck asynchronously.\n\n[Govulncheck](https://go.dev/blog/vuln) is a static analysis tool that\ncomputes the set of functions reachable within your application, including\ndependencies; queries a database of known security vulnerabilities; and\nreports any potential problems it finds.\n",
 			"Default": false
 		},
 		{
@@ -977,6 +982,13 @@
 			"Title": "Update vendor directory",
 			"Doc": "\nThis codelens source annotates the `module` directive in a\ngo.mod file with a command to run [`go mod\nvendor`](https://go.dev/ref/mod#go-mod-vendor), which\ncreates or updates the directory named `vendor` in the\nmodule root so that it contains an up-to-date copy of all\nnecessary package dependencies.\n",
 			"Default": true
+		},
+		{
+			"FileType": "go.mod",
+			"Lens": "vulncheck",
+			"Title": "Run govulncheck",
+			"Doc": "\nThis codelens source annotates the `module` directive in a go.mod file\nwith a command to run govulncheck synchronously.\n\n[Govulncheck](https://go.dev/blog/vuln) is a static analysis tool that\ncomputes the set of functions reachable within your application, including\ndependencies; queries a database of known security vulnerabilities; and\nreports any potential problems it finds.\n",
+			"Default": false
 		}
 	],
 	"Analyzers": [