make SSA sanity checks opt-in for builds

Author: cpunion

internal/build/build.go

@@ -384,7 +384,7 @@ func Do(args []string, conf *Config) ([]Package, error) {
 	})
 	preCollectRuntimeLinknames(prog, altPkgs)
 
-	buildMode := ssaBuildMode
+	buildMode := ssaBuildMode()
 	cabiOptimize := true
 	passOpt := true
 	if IsDbgEnabled() || mode == ModeGen {
@@ -571,9 +571,17 @@ func (p Package) isNeedRuntimeOrPyInit() (needRuntime, needPyInit bool) {
 	return
 }
 
-const (
-	ssaBuildMode = ssa.SanityCheckFunctions | ssa.InstantiateGenerics
-)
+func ssaBuildMode() ssa.BuilderMode {
+	mode := ssa.InstantiateGenerics
+	if ssaSanityEnabled() {
+		mode |= ssa.SanityCheckFunctions
+	}
+	return mode
+}
+
+func ssaSanityEnabled() bool {
+	return isEnvOn(llgoSSASanity, false)
+}
 
 type context struct {
 	env            *llvm.Env
@@ -1767,9 +1775,11 @@ func fixUntypedShiftTypes(p *packages.Package) {
 }
 
 func applyPatches(ctx *context, p *packages.Package, verbose bool) {
-	// Fix untyped shift types before SSA build
+	// Fix untyped shift types before SSA sanity checking.
 	// See: https://github.com/golang/go/issues/77067
-	fixUntypedShiftTypes(p)
+	if ssaSanityEnabled() {
+		fixUntypedShiftTypes(p)
+	}
 
 	// fix instance patch
 	for id, inst := range p.TypesInfo.Instances {
@@ -1839,6 +1849,7 @@ const llgoWasiThreads = "LLGO_WASI_THREADS"
 const llgoStdioNobuf = "LLGO_STDIO_NOBUF"
 const llgoFullRpath = "LLGO_FULL_RPATH"
 const llgoBuildCache = "LLGO_BUILD_CACHE"
+const llgoSSASanity = "LLGO_SSA_SANITY"
 
 // for Plan9 asm translation debug
 const llgoPlan9ASMPkgs = "LLGO_PLAN9ASM_PKGS"

internal/build/build_test.go

@@ -20,6 +20,7 @@ import (
 	"github.com/goplus/llgo/internal/mockable"
 	"github.com/goplus/llgo/internal/packages"
 	llssa "github.com/goplus/llgo/ssa"
+	gossa "golang.org/x/tools/go/ssa"
 )
 
 func TestMain(m *testing.M) {
@@ -52,6 +53,27 @@ func TestPrependEnvPath(t *testing.T) {
 	}
 }
 
+func TestSSABuildModeSanityOptIn(t *testing.T) {
+	t.Setenv(llgoSSASanity, "")
+	if ssaSanityEnabled() {
+		t.Fatal("SSA sanity should default to disabled")
+	}
+	if got := ssaBuildMode(); got&gossa.SanityCheckFunctions != 0 {
+		t.Fatalf("default SSA build mode enables sanity checks: %v", got)
+	}
+	if got := ssaBuildMode(); got&gossa.InstantiateGenerics == 0 {
+		t.Fatalf("default SSA build mode does not instantiate generics: %v", got)
+	}
+
+	t.Setenv(llgoSSASanity, "1")
+	if !ssaSanityEnabled() {
+		t.Fatal("SSA sanity should be enabled by LLGO_SSA_SANITY=1")
+	}
+	if got := ssaBuildMode(); got&gossa.SanityCheckFunctions == 0 {
+		t.Fatalf("opt-in SSA build mode does not enable sanity checks: %v", got)
+	}
+}
+
 func TestNeedsLinuxNoPIE(t *testing.T) {
 	ctx := &context{buildConf: &Config{Goos: "linux"}}
 	if !needsLinuxNoPIE(ctx, nil) {

internal/build/collect.go

@@ -100,6 +100,7 @@ func (c *context) envInputs() envSection {
 		llgoWasiThreads,
 		llgoStdioNobuf,
 		llgoFullRpath,
+		llgoSSASanity,
 	}
 	for _, envVar := range envVars {
 		if v := os.Getenv(envVar); v != "" {