compiler: support pragmas on generic functions

Author: aykevl

compiler/symbol.go

@@ -250,10 +250,14 @@ func (c *compilerContext) getFunctionInfo(f *ssa.Function) functionInfo {
 // parsePragmas is used by getFunctionInfo to parse function pragmas such as
 // //export or //go:noinline.
 func (c *compilerContext) parsePragmas(info *functionInfo, f *ssa.Function) {
-	if f.Syntax() == nil {
+	syntax := f.Syntax()
+	if f.Origin() != nil {
+		syntax = f.Origin().Syntax()
+	}
+	if syntax == nil {
 		return
 	}
-	if decl, ok := f.Syntax().(*ast.FuncDecl); ok && decl.Doc != nil {
+	if decl, ok := syntax.(*ast.FuncDecl); ok && decl.Doc != nil {
 		for _, comment := range decl.Doc.List {
 			text := comment.Text
 			if strings.HasPrefix(text, "//export ") {

compiler/testdata/pragma.go

@@ -48,6 +48,22 @@ func inlineFunc() {
 func noinlineFunc() {
 }
 
+type Int interface {
+	int8 | int16
+}
+
+// Same for generic functions (but the compiler may miss the pragma due to it
+// being generic).
+//
+//go:noinline
+func noinlineGenericFunc[T Int]() {
+}
+
+func useGeneric() {
+	// Make sure the generic function above is instantiated.
+	noinlineGenericFunc[int8]()
+}
+
 // This function should have the specified section.
 //
 //go:section .special_function_section

compiler/testdata/pragma.ll

@@ -48,6 +48,19 @@ entry:
   ret void
 }
 
+; Function Attrs: nounwind
+define hidden void @main.useGeneric(ptr %context) unnamed_addr #2 {
+entry:
+  call void @"main.noinlineGenericFunc[int8]"(ptr undef)
+  ret void
+}
+
+; Function Attrs: noinline nounwind
+define linkonce_odr hidden void @"main.noinlineGenericFunc[int8]"(ptr %context) unnamed_addr #5 {
+entry:
+  ret void
+}
+
 ; Function Attrs: noinline nounwind
 define hidden void @main.functionInSection(ptr %context) unnamed_addr #5 section ".special_function_section" {
 entry: