[clang] bdb309c - [clang][modules] Avoid modules diagnostics for `__has_include()` (#71450)

[via cfe-commits]

Author: Jan Svoboda
Date: 2023-11-06T17:31:27-08:00
New Revision: bdb309c5fd4030ae6ff9d5114e3532d45a98a183

URL: https://github.com/llvm/llvm-project/commit/bdb309c5fd4030ae6ff9d5114e3532d45a98a183
DIFF: https://github.com/llvm/llvm-project/commit/bdb309c5fd4030ae6ff9d5114e3532d45a98a183.diff

LOG: [clang][modules] Avoid modules diagnostics for `__has_include()` (#71450)

After #70144 Clang started resolving module maps even for
`__has_include()` expressions. This had the unintended consequence of
emitting diagnostics around header misuse. These don't make sense if you
actually don't bring contents of the header into the importer, so should
be skipped for `__has_include()`. This patch moves emission of these
diagnostics out of `Preprocessor::LookupFile()` up into
`Preprocessor::LookupHeaderIncludeOrImport()`.

Added: 
    clang/test/Modules/has_include_non_modular.c

Modified: 
    clang/lib/Lex/PPDirectives.cpp

Removed: 
    


################################################################################
diff  --git a/clang/lib/Lex/PPDirectives.cpp b/clang/lib/Lex/PPDirectives.cpp
index d97a103833c2fa6..956e2276f25b710 100644
--- a/clang/lib/Lex/PPDirectives.cpp
+++ b/clang/lib/Lex/PPDirectives.cpp
@@ -960,7 +960,6 @@ OptionalFileEntryRef Preprocessor::LookupFile(
 
   Module *RequestingModule = getModuleForLocation(
       FilenameLoc, LangOpts.ModulesValidateTextualHeaderIncludes);
-  bool RequestingModuleIsModuleInterface = !SourceMgr.isInMainFile(FilenameLoc);
 
   // If the header lookup mechanism may be relative to the current inclusion
   // stack, record the parent #includes.
@@ -1041,13 +1040,8 @@ OptionalFileEntryRef Preprocessor::LookupFile(
       Filename, FilenameLoc, isAngled, FromDir, &CurDir, Includers, SearchPath,
       RelativePath, RequestingModule, SuggestedModule, IsMapped,
       IsFrameworkFound, SkipCache, BuildSystemModule, OpenFile, CacheFailures);
-  if (FE) {
-    if (SuggestedModule && !LangOpts.AsmPreprocessor)
-      HeaderInfo.getModuleMap().diagnoseHeaderInclusion(
-          RequestingModule, RequestingModuleIsModuleInterface, FilenameLoc,
-          Filename, *FE);
+  if (FE)
     return FE;
-  }
 
   OptionalFileEntryRef CurFileEnt;
   // Otherwise, see if this is a subframework header.  If so, this is relative
@@ -1058,10 +1052,6 @@ OptionalFileEntryRef Preprocessor::LookupFile(
       if (OptionalFileEntryRef FE = HeaderInfo.LookupSubframeworkHeader(
               Filename, *CurFileEnt, SearchPath, RelativePath, RequestingModule,
               SuggestedModule)) {
-        if (SuggestedModule && !LangOpts.AsmPreprocessor)
-          HeaderInfo.getModuleMap().diagnoseHeaderInclusion(
-              RequestingModule, RequestingModuleIsModuleInterface, FilenameLoc,
-              Filename, *FE);
         return FE;
       }
     }
@@ -1073,10 +1063,6 @@ OptionalFileEntryRef Preprocessor::LookupFile(
         if (OptionalFileEntryRef FE = HeaderInfo.LookupSubframeworkHeader(
                 Filename, *CurFileEnt, SearchPath, RelativePath,
                 RequestingModule, SuggestedModule)) {
-          if (SuggestedModule && !LangOpts.AsmPreprocessor)
-            HeaderInfo.getModuleMap().diagnoseHeaderInclusion(
-                RequestingModule, RequestingModuleIsModuleInterface,
-                FilenameLoc, Filename, *FE);
           return FE;
         }
       }
@@ -2027,12 +2013,28 @@ OptionalFileEntryRef Preprocessor::LookupHeaderIncludeOrImport(
     const FileEntry *LookupFromFile, StringRef &LookupFilename,
     SmallVectorImpl<char> &RelativePath, SmallVectorImpl<char> &SearchPath,
     ModuleMap::KnownHeader &SuggestedModule, bool isAngled) {
+  auto DiagnoseHeaderInclusion = [&](FileEntryRef FE) {
+    if (LangOpts.AsmPreprocessor)
+      return;
+
+    Module *RequestingModule = getModuleForLocation(
+        FilenameLoc, LangOpts.ModulesValidateTextualHeaderIncludes);
+    bool RequestingModuleIsModuleInterface =
+        !SourceMgr.isInMainFile(FilenameLoc);
+
+    HeaderInfo.getModuleMap().diagnoseHeaderInclusion(
+        RequestingModule, RequestingModuleIsModuleInterface, FilenameLoc,
+        Filename, FE);
+  };
+
   OptionalFileEntryRef File = LookupFile(
       FilenameLoc, LookupFilename, isAngled, LookupFrom, LookupFromFile, CurDir,
       Callbacks ? &SearchPath : nullptr, Callbacks ? &RelativePath : nullptr,
       &SuggestedModule, &IsMapped, &IsFrameworkFound);
-  if (File)
+  if (File) {
+    DiagnoseHeaderInclusion(*File);
     return File;
+  }
 
   // Give the clients a chance to silently skip this include.
   if (Callbacks && Callbacks->FileNotFound(Filename))
@@ -2051,6 +2053,7 @@ OptionalFileEntryRef Preprocessor::LookupHeaderIncludeOrImport(
         &SuggestedModule, &IsMapped,
         /*IsFrameworkFound=*/nullptr);
     if (File) {
+      DiagnoseHeaderInclusion(*File);
       Diag(FilenameTok, diag::err_pp_file_not_found_angled_include_not_fatal)
           << Filename << IsImportDecl
           << FixItHint::CreateReplacement(FilenameRange,
@@ -2081,6 +2084,7 @@ OptionalFileEntryRef Preprocessor::LookupHeaderIncludeOrImport(
         Callbacks ? &RelativePath : nullptr, &SuggestedModule, &IsMapped,
         /*IsFrameworkFound=*/nullptr);
     if (File) {
+      DiagnoseHeaderInclusion(*File);
       auto Hint =
           isAngled ? FixItHint::CreateReplacement(
                          FilenameRange, "<" + TypoCorrectionName.str() + ">")

diff  --git a/clang/test/Modules/has_include_non_modular.c b/clang/test/Modules/has_include_non_modular.c
new file mode 100644
index 000000000000000..2e1a06bdc6e4a0d
--- /dev/null
+++ b/clang/test/Modules/has_include_non_modular.c
@@ -0,0 +1,14 @@
+// RUN: rm -rf %t
+// RUN: split-file %s %t
+
+//--- module.modulemap
+module Mod { header "mod.h" }
+//--- mod.h
+#if __has_include("textual.h")
+#endif
+//--- textual.h
+
+//--- tu.c
+#include "mod.h"
+
+// RUN: %clang -fsyntax-only %t/tu.c -fmodules -fmodules-cache-path=%t/cache -Werror=non-modular-include-in-module