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[WIP] internal/build: fix linkname support main.sym #2155

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[WIP] internal/build: fix linkname support main.sym #2155

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e7e98d5
internal/build: fix linkname support main.sym
visualfc Jul 22, 2026
5cdaa13
_demo/go/export: export main.sym
visualfc Jul 24, 2026
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2 changes: 1 addition & 1 deletion _demo/go/export/libexport.h.want
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Expand Up @@ -311,7 +311,7 @@ GoString
TwoParams(intptr_t a, GoString b);

void
github_com_goplus_llgo__demo_go_export_init(void) GO_SYMBOL_RENAME("github.com/goplus/llgo/_demo/go/export.init")
main_init(void) GO_SYMBOL_RENAME("main.init")



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2 changes: 1 addition & 1 deletion _demo/go/export/use/main.c
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Expand Up @@ -36,7 +36,7 @@ int main() {

// Initialize packages - call init functions first
github_com_goplus_llgo__demo_go_export_c_init();
github_com_goplus_llgo__demo_go_export_init();
main_init();

// Verify that funcinfo is not merely linkable: runtime.Callers must yield
// a symbolized frame and runtime.FuncForPC must resolve that PC's details.
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14 changes: 14 additions & 0 deletions _demo/go/mainlink/main.go
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@@ -0,0 +1,14 @@
package main

import _ "unsafe"

func main() {
linkdemo()
}

func demo() {
println("demo")
}

//go:linkname linkdemo main.demo
func linkdemo()
6 changes: 6 additions & 0 deletions internal/build/build.go
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Expand Up @@ -689,6 +689,9 @@ func filterTestPackages(initial []*packages.Package, outFile string) ([]*package
if needLink(pkg, ModeTest) {
filtered = append(filtered, pkg)
}
if pkg.Types != nil && pkg.Types.Name() == "main" {
pkg.Types.SetName("main.test")
}
}
if len(filtered) > 1 && outFile != "" {
return nil, fmt.Errorf("cannot use -o flag with multiple packages")
Expand Down Expand Up @@ -1132,6 +1135,9 @@ func linkMainPkg(ctx *context, pkg *packages.Package, pkgs []*aPackage, outputPa
methodByName := make(map[string]none)
allPkgs := []*packages.Package{pkg}
for _, v := range pkgs {
if v.PkgPath != pkg.PkgPath && v.Types.Name() == "main" {

@fennoai fennoai Bot Jul 23, 2026

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v.Types.Name() is dereferenced without a nil check, unlike the guard added a few lines up in filterTestPackages (if pkg.Types != nil && pkg.Types.Name() == "main", line 692). Elsewhere in this file p.Types is defensively nil-checked before use. A package with Types == nil (e.g. an ill-typed or synthetically-loaded dep) reaching this loop would panic. Recommend v.Types != nil && v.Types.Name() == "main" for consistency and crash-safety.

continue
}
allPkgs = append(allPkgs, v.Package)
}
visitRoots := allPkgs
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11 changes: 9 additions & 2 deletions internal/build/main_module.go
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Expand Up @@ -110,8 +110,15 @@ func genMainModule(ctx *context, rtPkgPath string, pkg *packages.Package, cfg *g
})
}

mainInit := declareNoArgFunc(mainPkg, pkg.PkgPath+".init")
mainMain := declareNoArgFunc(mainPkg, pkg.PkgPath+".main")
var pkgPath string
if pkg.Types.Name() == "main" {

@fennoai fennoai Bot Jul 23, 2026

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pkg.Types.Name() is dereferenced without a nil guard here, whereas filterTestPackages guards the same access with pkg.Types != nil. If pkg.Types can ever be nil at this point, this panics. Add the nil check (or centralize via abi.PathOf, which already special-cases main) so the three new Name()=="main" sites behave consistently.

pkgPath = "main"
} else {
pkgPath = pkg.PkgPath
}

mainInit := declareNoArgFunc(mainPkg, pkgPath+".init")
mainMain := declareNoArgFunc(mainPkg, pkgPath+".main")

entryFn := defineEntryFunction(ctx, mainPkg, argcVar, argvVar, argvValueType, entryFunctions{
runtimeStub: runtimeStub,
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2 changes: 1 addition & 1 deletion internal/cabi/cabi_test.go
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Expand Up @@ -155,7 +155,7 @@ func testModule(t *testing.T, ctx context, td llvm.TargetData, m llvm.Module, c
// check c linkname
testFunc(t, ctx, td, m.NamedFunction(fn.Name()), fn)
// check go
testFunc(t, ctx, td, m.NamedFunction("command-line-arguments."+fn.Name()), fn)
testFunc(t, ctx, td, m.NamedFunction("main."+fn.Name()), fn)
}
}

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3 changes: 3 additions & 0 deletions ssa/abi/abi.go
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Expand Up @@ -284,6 +284,9 @@ func PathOf(pkg *types.Package) string {
if pkg == nil {
return ""
}
if pkg.Name() == "main" {
return "main"
}
return strings.TrimPrefix(pkg.Path(), PatchPathPrefix)
}

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2 changes: 1 addition & 1 deletion ssa/abitype.go
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Expand Up @@ -506,7 +506,7 @@ func methodExprSignature(sig *types.Signature) *types.Signature {
func (b Builder) abiMethodFunc(anonymous bool, mPkg *types.Package, mName string, mSig *types.Signature) Function {
var fullName string
if anonymous {
fullName = b.Pkg.Path() + "." + mSig.Recv().Type().String() + "." + mName
fullName = b.Pkg.Path() + "." + types.TypeString(mSig.Recv().Type(), abi.PathOf) + "." + mName
} else {
fullName = FuncName(mPkg, mName, mSig.Recv(), false)
}
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