Commit 570ffc470e

@@ -1734,6 +1734,31 @@ bool ZigClangFunctionDecl_doesDeclarationForceExternallyVisibleDefinition(const
     return casted->doesDeclarationForceExternallyVisibleDefinition();
 }
 
+bool ZigClangFunctionDecl_isThisDeclarationADefinition(const struct ZigClangFunctionDecl *self) {
+    auto casted = reinterpret_cast<const clang::FunctionDecl *>(self);
+    return casted->isThisDeclarationADefinition();
+}
+
+bool ZigClangFunctionDecl_doesThisDeclarationHaveABody(const struct ZigClangFunctionDecl *self) {
+    auto casted = reinterpret_cast<const clang::FunctionDecl *>(self);
+    return casted->doesThisDeclarationHaveABody();
+}
+
+bool ZigClangFunctionDecl_isDefined(const struct ZigClangFunctionDecl *self) {
+    auto casted = reinterpret_cast<const clang::FunctionDecl *>(self);
+    return casted->isDefined();
+}
+
+const ZigClangFunctionDecl* ZigClangFunctionDecl_getDefinition(const struct ZigClangFunctionDecl *self) {
+    auto casted = reinterpret_cast<const clang::FunctionDecl *>(self);
+    return reinterpret_cast<const ZigClangFunctionDecl *>(casted->getDefinition());
+}
+
+bool ZigClangTagDecl_isThisDeclarationADefinition(const struct ZigClangTagDecl *self) {
+    auto casted = reinterpret_cast<const clang::TagDecl *>(self);
+    return casted->isThisDeclarationADefinition();
+}
+
 bool ZigClangFunctionDecl_isInlineSpecified(const struct ZigClangFunctionDecl *self) {
     auto casted = reinterpret_cast<const clang::FunctionDecl *>(self);
     return casted->isInlineSpecified();

@@ -854,6 +854,8 @@ ZIG_EXTERN_C enum ZigClangPreprocessedEntity_EntityKind ZigClangPreprocessedEnti
 ZIG_EXTERN_C const struct ZigClangRecordDecl *ZigClangRecordType_getDecl(const struct ZigClangRecordType *record_ty);
 ZIG_EXTERN_C const struct ZigClangEnumDecl *ZigClangEnumType_getDecl(const struct ZigClangEnumType *record_ty);
 
+ZIG_EXTERN_C bool ZigClangTagDecl_isThisDeclarationADefinition(const struct ZigClangTagDecl *);
+
 ZIG_EXTERN_C const struct ZigClangTagDecl *ZigClangRecordDecl_getCanonicalDecl(const struct ZigClangRecordDecl *record_decl);
 ZIG_EXTERN_C const struct ZigClangTagDecl *ZigClangEnumDecl_getCanonicalDecl(const struct ZigClangEnumDecl *);
 ZIG_EXTERN_C const struct ZigClangFieldDecl *ZigClangFieldDecl_getCanonicalDecl(const ZigClangFieldDecl *);
@@ -880,7 +882,11 @@ ZIG_EXTERN_C enum ZigClangStorageClass ZigClangFunctionDecl_getStorageClass(cons
 ZIG_EXTERN_C const struct ZigClangParmVarDecl *ZigClangFunctionDecl_getParamDecl(const struct ZigClangFunctionDecl *, unsigned i);
 ZIG_EXTERN_C const struct ZigClangStmt *ZigClangFunctionDecl_getBody(const struct ZigClangFunctionDecl *);
 ZIG_EXTERN_C bool ZigClangFunctionDecl_doesDeclarationForceExternallyVisibleDefinition(const struct ZigClangFunctionDecl *);
+ZIG_EXTERN_C bool ZigClangFunctionDecl_isThisDeclarationADefinition(const struct ZigClangFunctionDecl *);
+ZIG_EXTERN_C bool ZigClangFunctionDecl_doesThisDeclarationHaveABody(const struct ZigClangFunctionDecl *);
 ZIG_EXTERN_C bool ZigClangFunctionDecl_isInlineSpecified(const struct ZigClangFunctionDecl *);
+ZIG_EXTERN_C bool ZigClangFunctionDecl_isDefined(const struct ZigClangFunctionDecl *);
+ZIG_EXTERN_C const struct ZigClangFunctionDecl* ZigClangFunctionDecl_getDefinition(const struct ZigClangFunctionDecl *);
 ZIG_EXTERN_C const char* ZigClangFunctionDecl_getSectionAttribute(const struct ZigClangFunctionDecl *, size_t *);
 
 ZIG_EXTERN_C bool ZigClangRecordDecl_isUnion(const struct ZigClangRecordDecl *record_decl);

@@ -761,6 +761,7 @@ pub extern fn ZigClangASTUnit_getASTContext(self: ?*struct_ZigClangASTUnit) ?*st
 pub extern fn ZigClangASTUnit_getSourceManager(self: *struct_ZigClangASTUnit) *struct_ZigClangSourceManager;
 pub extern fn ZigClangASTUnit_visitLocalTopLevelDecls(self: *struct_ZigClangASTUnit, context: ?*c_void, Fn: ?extern fn (?*c_void, *const struct_ZigClangDecl) bool) bool;
 pub extern fn ZigClangRecordType_getDecl(record_ty: ?*const struct_ZigClangRecordType) *const struct_ZigClangRecordDecl;
+pub extern fn ZigClangTagDecl_isThisDeclarationADefinition(self: *const ZigClangTagDecl) bool;
 pub extern fn ZigClangEnumType_getDecl(record_ty: ?*const struct_ZigClangEnumType) *const struct_ZigClangEnumDecl;
 pub extern fn ZigClangRecordDecl_getCanonicalDecl(record_decl: ?*const struct_ZigClangRecordDecl) ?*const struct_ZigClangTagDecl;
 pub extern fn ZigClangFieldDecl_getCanonicalDecl(field_decl: ?*const struct_ZigClangFieldDecl) ?*const struct_ZigClangFieldDecl;
@@ -847,7 +848,11 @@ pub extern fn ZigClangFunctionDecl_getStorageClass(self: *const ZigClangFunction
 pub extern fn ZigClangFunctionDecl_getParamDecl(self: *const ZigClangFunctionDecl, i: c_uint) *const struct_ZigClangParmVarDecl;
 pub extern fn ZigClangFunctionDecl_getBody(self: *const ZigClangFunctionDecl) *const struct_ZigClangStmt;
 pub extern fn ZigClangFunctionDecl_doesDeclarationForceExternallyVisibleDefinition(self: *const ZigClangFunctionDecl) bool;
+pub extern fn ZigClangFunctionDecl_isThisDeclarationADefinition(self: *const ZigClangFunctionDecl) bool;
+pub extern fn ZigClangFunctionDecl_doesThisDeclarationHaveABody(self: *const ZigClangFunctionDecl) bool;
 pub extern fn ZigClangFunctionDecl_isInlineSpecified(self: *const ZigClangFunctionDecl) bool;
+pub extern fn ZigClangFunctionDecl_isDefined(self: *const ZigClangFunctionDecl) bool;
+pub extern fn ZigClangFunctionDecl_getDefinition(self: *const ZigClangFunctionDecl) ?*const struct_ZigClangFunctionDecl;
 pub extern fn ZigClangFunctionDecl_getSectionAttribute(self: *const ZigClangFunctionDecl, len: *usize) ?[*]const u8;
 
 pub extern fn ZigClangBuiltinType_getKind(self: *const struct_ZigClangBuiltinType) ZigClangBuiltinTypeKind;

@@ -414,6 +414,13 @@ fn visitFnDecl(c: *Context, fn_decl: *const ZigClangFunctionDecl) Error!void {
     const fn_name = try c.str(ZigClangDecl_getName_bytes_begin(@ptrCast(*const ZigClangDecl, fn_decl)));
     if (c.global_scope.sym_table.contains(fn_name))
         return; // Avoid processing this decl twice
+
+    // Skip this declaration if a proper definition exists
+    if (!ZigClangFunctionDecl_isThisDeclarationADefinition(fn_decl)) {
+        if (ZigClangFunctionDecl_getDefinition(fn_decl)) |def|
+            return visitFnDecl(c, def);
+    }
+
     const rp = makeRestorePoint(c);
     const fn_decl_loc = ZigClangFunctionDecl_getLocation(fn_decl);
     const has_body = ZigClangFunctionDecl_hasBody(fn_decl);
@@ -671,7 +678,7 @@ fn transTypeDef(c: *Context, typedef_decl: *const ZigClangTypedefNameDecl, top_l
         return transTypeDefAsBuiltin(c, typedef_decl, "isize")
     else if (mem.eql(u8, checked_name, "size_t"))
         return transTypeDefAsBuiltin(c, typedef_decl, "usize");
-    
+
     if (!top_level_visit) {
         return transCreateNodeIdentifier(c, checked_name);
     }
@@ -703,7 +710,9 @@ fn transRecordDecl(c: *Context, record_decl: *const ZigClangRecordDecl) Error!?*
 
     var bare_name = try c.str(ZigClangDecl_getName_bytes_begin(@ptrCast(*const ZigClangDecl, record_decl)));
     var is_unnamed = false;
-    if (ZigClangRecordDecl_isAnonymousStructOrUnion(record_decl) or bare_name.len == 0) {
+    // Record declarations such as `struct {...} x` have no name but they're not
+    // anonymous hence here isAnonymousStructOrUnion is not needed
+    if (bare_name.len == 0) {
         bare_name = try std.fmt.allocPrint(c.a(), "unnamed_{}", .{c.getMangle()});
         is_unnamed = true;
     }
@@ -769,7 +778,7 @@ fn transRecordDecl(c: *Context, record_decl: *const ZigClangRecordDecl) Error!?*
 
             var is_anon = false;
             var raw_name = try c.str(ZigClangDecl_getName_bytes_begin(@ptrCast(*const ZigClangDecl, field_decl)));
-            if (ZigClangFieldDecl_isAnonymousStructOrUnion(field_decl) or raw_name.len == 0) {
+            if (ZigClangFieldDecl_isAnonymousStructOrUnion(field_decl)) {
                 raw_name = try std.fmt.allocPrint(c.a(), "unnamed_{}", .{c.getMangle()});
                 is_anon = true;
             }

@@ -3,6 +3,16 @@ const tests = @import("tests.zig");
 const nl = std.cstr.line_sep;
 
 pub fn addCases(cases: *tests.RunTranslatedCContext) void {
+    cases.add("forward declarations",
+        \\#include <stdlib.h>
+        \\int foo(int);
+        \\int foo(int x) { return x + 1; }
+        \\int main(int argc, char **argv) {
+        \\    if (foo(2) != 3) abort();
+        \\    return 0;
+        \\}
+    , "");
+
     cases.add("typedef and function pointer",
         \\#include <stdlib.h>
         \\typedef struct _Foo Foo;
@@ -18,7 +28,7 @@ pub fn addCases(cases: *tests.RunTranslatedCContext) void {
         \\    return 0;
         \\}
     , "");
-    
+
     cases.add("ternary operator",
         \\#include <stdlib.h>
         \\static int cnt = 0;