Improve callgraph field dereference

.github/workflows/build_and_test.yml

@@ -18,7 +18,7 @@ jobs:
     - name: Setup Go
       uses: actions/setup-go@v4
       with:
-        go-version: '1.21'
+        go-version-file: go.mod
 
     - name: Build
       run: go build -v ./...

callgraphutil/graph.go

@@ -3,6 +3,7 @@ package callgraphutil
 import (
 	"bytes"
 	"fmt"
+	"go/token"
 	"go/types"
 
 	"golang.org/x/tools/go/callgraph"
@@ -48,19 +49,34 @@ func NewGraph(root *ssa.Function, srcFns ...*ssa.Function) (*callgraph.Graph, er
 
 	allFns := ssautil.AllFunctions(root.Prog)
 
-	for _, srcFn := range srcFns {
-		// debug("adding src function %d/%d: %v\n", i+1, len(srcFns), srcFn)
+	visited := make(map[*ssa.Function]bool)
 
-		err := AddFunction(g, srcFn, allFns)
-		if err != nil {
-			return g, fmt.Errorf("failed to add src function %v: %w", srcFn, err)
+	var walkFn func(fn *ssa.Function) error
+	walkFn = func(fn *ssa.Function) error {
+		if visited[fn] {
+			return nil
+		}
+		visited[fn] = true
+
+		if err := AddFunction(g, fn, allFns); err != nil {
+			return fmt.Errorf("failed to add function %v: %w", fn, err)
 		}
 
-		for _, block := range srcFn.DomPreorder() {
+		for _, block := range fn.DomPreorder() {
 			for _, instr := range block.Instrs {
-				checkBlockInstruction(root, allFns, g, srcFn, instr)
+				if err := checkBlockInstruction(root, allFns, g, fn, instr, walkFn); err != nil {
+					return err
+				}
 			}
 		}
+
+		return nil
+	}
+
+	for _, srcFn := range srcFns {
+		if err := walkFn(srcFn); err != nil {
+			return g, err
+		}
 	}
 
 	return g, nil
@@ -69,7 +85,7 @@ func NewGraph(root *ssa.Function, srcFns ...*ssa.Function) (*callgraph.Graph, er
 // checkBlockInstruction checks the given instruction for any function calls, adding
 // edges to the call graph as needed and recursively adding any new functions to the graph
 // that are discovered during the process (typically via interface methods).
-func checkBlockInstruction(root *ssa.Function, allFns map[*ssa.Function]bool, g *callgraph.Graph, fn *ssa.Function, instr ssa.Instruction) error {
+func checkBlockInstruction(root *ssa.Function, allFns map[*ssa.Function]bool, g *callgraph.Graph, fn *ssa.Function, instr ssa.Instruction, walkFn func(*ssa.Function) error) error {
 	// debug("\tcheckBlockInstruction: %v\n", instr)
 	switch instrt := instr.(type) {
 	case *ssa.Call:
@@ -159,6 +175,15 @@ func checkBlockInstruction(root *ssa.Function, allFns map[*ssa.Function]bool, g
 			case *ssa.Function:
 				instrCall = calltFn
 			}
+		case *ssa.UnOp:
+			if callt.Op == token.MUL {
+				switch fa := callt.X.(type) {
+				case *ssa.FieldAddr:
+					instrCall = findFunctionInField(fa, allFns)
+				case *ssa.Field:
+					instrCall = findFunctionInFieldValue(fa, allFns)
+				}
+			}
 		case *ssa.Parameter:
 			// This is likely a method call, so we need to
 			// get the function from the method receiver which
@@ -204,6 +229,10 @@ func checkBlockInstruction(root *ssa.Function, allFns map[*ssa.Function]bool, g
 			return fmt.Errorf("failed to add function %v from block instr: %w", instrCall, err)
 		}
 
+		if err := walkFn(instrCall); err != nil {
+			return err
+		}
+
 		// attempt to link function arguments that are functions
 		for a := 0; a < len(instrt.Call.Args); a++ {
 			arg := instrt.Call.Args[a]
@@ -306,3 +335,61 @@ func AddFunction(cg *callgraph.Graph, target *ssa.Function, allFns map[*ssa.Func
 
 	return nil
 }
+
+// findFunctionInField scans all functions for assignments to the provided
+// struct field address and returns the first discovered function value.
+func findFunctionInField(fieldAddr *ssa.FieldAddr, allFns map[*ssa.Function]bool) *ssa.Function {
+	idx := fieldAddr.Field
+	structType := fieldAddr.X.Type()
+
+	for fn := range allFns {
+		for _, blk := range fn.Blocks {
+			for _, ins := range blk.Instrs {
+				if store, ok := ins.(*ssa.Store); ok {
+					if fa, ok := store.Addr.(*ssa.FieldAddr); ok {
+						if fa.Field == idx && types.Identical(fa.X.Type(), structType) {
+							switch v := store.Val.(type) {
+							case *ssa.Function:
+								return v
+							case *ssa.MakeClosure:
+								if f, ok := v.Fn.(*ssa.Function); ok {
+									return f
+								}
+							}
+						}
+					}
+				}
+			}
+		}
+	}
+	return nil
+}
+
+// findFunctionInFieldValue searches for function assignments made to the struct
+// field represented by the given Field value.
+func findFunctionInFieldValue(field *ssa.Field, allFns map[*ssa.Function]bool) *ssa.Function {
+	idx := field.Field
+	structType := field.X.Type()
+
+	for fn := range allFns {
+		for _, blk := range fn.Blocks {
+			for _, ins := range blk.Instrs {
+				if store, ok := ins.(*ssa.Store); ok {
+					if fa, ok := store.Addr.(*ssa.FieldAddr); ok {
+						if fa.Field == idx && types.Identical(fa.X.Type(), structType) {
+							switch v := store.Val.(type) {
+							case *ssa.Function:
+								return v
+							case *ssa.MakeClosure:
+								if f, ok := v.Fn.(*ssa.Function); ok {
+									return f
+								}
+							}
+						}
+					}
+				}
+			}
+		}
+	}
+	return nil
+}

callgraphutil/struct_field_test.go

@@ -0,0 +1,36 @@
+package callgraphutil_test
+
+import (
+	"context"
+	"path/filepath"
+	"testing"
+
+	"github.com/picatz/taint/callgraphutil"
+)
+
+func TestStructFieldCallGraph(t *testing.T) {
+	dir, err := filepath.Abs(filepath.Join("testdata"))
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	pkgs, err := loadPackages(context.Background(), dir, "./...")
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	mainFn, srcFns, err := loadSSA(context.Background(), pkgs)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	cg, err := loadCallGraph(context.Background(), mainFn, srcFns)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	target := "github.com/picatz/taint/callgraphutil/testdata.doSomething"
+	if paths := callgraphutil.PathsSearchCallTo(cg.Root, target); len(paths) == 0 {
+		t.Fatalf("expected path to %s", target)
+	}
+}

callgraphutil/testdata/struct_field_simple.go

@@ -0,0 +1,53 @@
+package main
+
+import (
+	"fmt"
+	"os"
+)
+
+type command struct {
+	name string
+	run  func(args []string) error
+}
+
+type commands []*command
+
+func (c commands) run(args []string) error {
+	for i := 0; i < len(c); i++ {
+		cmd := c[i]
+		if cmd.name == args[0] {
+			return cmd.run(args[1:])
+		}
+	}
+	return fmt.Errorf("unknown command: %s", args[0])
+}
+
+type cli struct {
+	commands commands
+}
+
+func (c *cli) run(args []string) error {
+	return c.commands.run(args)
+}
+
+func doSomething() error {
+	fmt.Println("doing something")
+	return nil
+}
+
+func main() {
+	c := &cli{
+		commands{
+			{
+				name: "do-something",
+				run: func(args []string) error {
+					return doSomething()
+				},
+			},
+		},
+	}
+
+	if err := c.run(os.Args[1:]); err != nil {
+		panic(err)
+	}
+}

go.mod

@@ -1,40 +1,45 @@
 module github.com/picatz/taint
 
-go 1.21
+go 1.24.4
 
 require (
-	github.com/charmbracelet/lipgloss v0.9.1
-	github.com/go-git/go-git/v5 v5.11.0
-	golang.org/x/term v0.18.0
-	golang.org/x/tools v0.16.1
+	github.com/charmbracelet/lipgloss v1.1.0
+	github.com/go-git/go-git/v5 v5.16.2
+	golang.org/x/term v0.32.0
+	golang.org/x/tools v0.34.0
 )
 
 require (
-	dario.cat/mergo v1.0.0 // indirect
-	github.com/Microsoft/go-winio v0.6.1 // indirect
-	github.com/ProtonMail/go-crypto v0.0.0-20230828082145-3c4c8a2d2371 // indirect
+	dario.cat/mergo v1.0.2 // indirect
+	github.com/Microsoft/go-winio v0.6.2 // indirect
+	github.com/ProtonMail/go-crypto v1.3.0 // indirect
 	github.com/aymanbagabas/go-osc52/v2 v2.0.1 // indirect
-	github.com/cloudflare/circl v1.3.7 // indirect
-	github.com/cyphar/filepath-securejoin v0.2.4 // indirect
+	github.com/charmbracelet/colorprofile v0.3.1 // indirect
+	github.com/charmbracelet/x/ansi v0.9.3 // indirect
+	github.com/charmbracelet/x/cellbuf v0.0.13 // indirect
+	github.com/charmbracelet/x/term v0.2.1 // indirect
+	github.com/cloudflare/circl v1.6.1 // indirect
+	github.com/cyphar/filepath-securejoin v0.4.1 // indirect
 	github.com/emirpasic/gods v1.18.1 // indirect
 	github.com/go-git/gcfg v1.5.1-0.20230307220236-3a3c6141e376 // indirect
-	github.com/go-git/go-billy/v5 v5.5.0 // indirect
-	github.com/golang/groupcache v0.0.0-20210331224755-41bb18bfe9da // indirect
+	github.com/go-git/go-billy/v5 v5.6.2 // indirect
+	github.com/golang/groupcache v0.0.0-20241129210726-2c02b8208cf8 // indirect
 	github.com/jbenet/go-context v0.0.0-20150711004518-d14ea06fba99 // indirect
 	github.com/kevinburke/ssh_config v1.2.0 // indirect
 	github.com/lucasb-eyer/go-colorful v1.2.0 // indirect
 	github.com/mattn/go-isatty v0.0.20 // indirect
-	github.com/mattn/go-runewidth v0.0.15 // indirect
-	github.com/muesli/reflow v0.3.0 // indirect
-	github.com/muesli/termenv v0.15.2 // indirect
-	github.com/pjbgf/sha1cd v0.3.0 // indirect
-	github.com/rivo/uniseg v0.4.4 // indirect
-	github.com/sergi/go-diff v1.1.0 // indirect
-	github.com/skeema/knownhosts v1.2.1 // indirect
+	github.com/mattn/go-runewidth v0.0.16 // indirect
+	github.com/muesli/termenv v0.16.0 // indirect
+	github.com/pjbgf/sha1cd v0.3.2 // indirect
+	github.com/rivo/uniseg v0.4.7 // indirect
+	github.com/sergi/go-diff v1.4.0 // indirect
+	github.com/skeema/knownhosts v1.3.1 // indirect
 	github.com/xanzy/ssh-agent v0.3.3 // indirect
-	golang.org/x/crypto v0.21.0 // indirect
-	golang.org/x/mod v0.14.0 // indirect
-	golang.org/x/net v0.23.0 // indirect
-	golang.org/x/sys v0.18.0 // indirect
+	github.com/xo/terminfo v0.0.0-20220910002029-abceb7e1c41e // indirect
+	golang.org/x/crypto v0.39.0 // indirect
+	golang.org/x/mod v0.25.0 // indirect
+	golang.org/x/net v0.41.0 // indirect
+	golang.org/x/sync v0.15.0 // indirect
+	golang.org/x/sys v0.33.0 // indirect
 	gopkg.in/warnings.v0 v0.1.2 // indirect
 )