Add -I adjustment to _3CASTBuilderAction.

Fixes #515.

clang/lib/3C/3C.cpp

@@ -102,13 +102,12 @@ class _3CASTBuilderAction : public ToolAction {
     // fixed another way, then making the path absolute would be sufficient to
     // fix https://github.com/correctcomputation/checkedc-clang/issues/515; the
     // path wouldn't need to be canonical.
-    std::error_code EC;
     SmallVectorImpl<FrontendInputFile> &Inputs = Invocation->getFrontendOpts().Inputs;
     for (FrontendInputFile *Iter = Inputs.begin(); Iter < Inputs.end(); Iter++) {
       FrontendInputFile &OldInput = *Iter;
       // getFile will assert that the input is a file, which should be true for 3C.
       std::string OldPath = std::string(OldInput.getFile()), NewPath;
-      EC = tryGetCanonicalFilePath(OldPath, NewPath);
+      std::error_code EC = tryGetCanonicalFilePath(OldPath, NewPath);
       if (EC) {
         errs() << "3C error: Failed to re-canonicalize source file path "
                << OldPath << " during compiler invocation "
@@ -119,6 +118,31 @@ class _3CASTBuilderAction : public ToolAction {
       *Iter = FrontendInputFile(NewPath, OldInput.getKind(), OldInput.isSystem());
     }
 
+    // Canonicalize -I paths to address the same two issues for `#include`d
+    // files. The situation is analogous except that this is not a complete fix
+    // for https://github.com/correctcomputation/checkedc-clang/issues/604
+    // because the portion of the path in the `#include` directive may be
+    // non-canonical.
+    HeaderSearchOptions &HeaderOpts = *Invocation->HeaderSearchOpts;
+    std::vector<HeaderSearchOptions::Entry> NewUserEntries;
+    for (auto It = HeaderOpts.UserEntries.begin(); It != HeaderOpts.UserEntries.end(); ) {
+      HeaderSearchOptions::Entry &Entry = *It;
+      std::string OldPath = Entry.Path, NewPath;
+      std::error_code EC = tryGetCanonicalFilePath(OldPath, NewPath);
+      if (EC) {
+        // Normally, if an -I directory isn't accessible, Clang seems to ignore
+        // it with no diagnostic. Hopefully, removing it from the list here will
+        // have the same effect and not break anything. If we kept the
+        // non-canonical entry, we might benefit from any diagnostic that Clang
+        // might issue in the future, but it's harder to reason about whether
+        // that might re-expose the original bugs.
+        It = HeaderOpts.UserEntries.erase(It);
+      } else {
+        Entry.Path = NewPath;
+        It++;
+      }
+    }
+
     // Finally, actually build the AST. This part is the same as in
     // ASTBuilderAction::runInvocation.
 

clang/tools/3c/utils/port_tools/generate_ccommands.py

@@ -133,7 +133,6 @@ def run3C(checkedc_bin, extra_3c_args,
 
     translation_units: List[TranslationUnitInfo] = []
     all_files = []
-    absolute_include_dirs = set()
     for i in cmds:
         file_to_add = i['file']
         compiler_path = None  # XXX Clean this up
@@ -165,9 +164,6 @@ def run3C(checkedc_bin, extra_3c_args,
                                      target_directory, file_to_add,
                                      output_filename)
             translation_units.append(tu)
-            for arg in compiler_x_args:
-                if arg.startswith('-I'):
-                    absolute_include_dirs.add(tu.realpath(arg[len('-I'):]))
 
     expandMacros(expand_macros_opts, compilation_base_dir, translation_units)
 
@@ -223,16 +219,6 @@ def run3C(checkedc_bin, extra_3c_args,
     args.append('-p')
     args.append(compile_commands_json)
     args.append('-extra-arg=-w')
-    # This is a workaround for a bug in Clang LibTooling that affects the use of
-    # relative paths with -I when different translation units have different
-    # working directories. For details, see
-    # https://github.com/correctcomputation/checkedc-clang/issues/515 .
-    #
-    # Even if the above issue were fixed, we may still need this in some cases
-    # to ensure that PersistentSourceLoc filenames are unambiguous: see the
-    # comment in _3CInterface::parseASTs in clang/lib/3C/3C.cpp .
-    for dir in absolute_include_dirs:
-        args.append('-extra-arg-before=-I' + dir)
     vcodewriter.addClangdArg("-log=verbose")
     vcodewriter.addClangdArg(args[1:])
     args.append('-base-dir="' + compilation_base_dir + '"')