When looking for the module associated with one of our magical builtin headers, specu...

The "magical" builtin headers are the headers we provide as part of
the C standard library, which typically comes from /usr/include. We
essentially merge our headers into that location (due to cyclic
dependencies). This change makes sure that, when header search finds
one of our builtin headers, we figure out which module it actually
lives in. This case is fairly rare; one ends up having to include one
of the few built-in C headers we provide before including anything
from /usr/include to trigger it. Fixes <rdar://problem/13787184>.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@180934 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Lex/ModuleMap.cpp b/lib/Lex/ModuleMap.cpp
index 0c03201aa6d42434213a69263a146b07e1d7ebcf..1458a73a7d32fde1d9c4f70920d6bf2db2633f92 100644 (file)
--- a/lib/Lex/ModuleMap.cpp
+++ b/lib/Lex/ModuleMap.cpp
@@ -149,6 +149,24 @@ static StringRef sanitizeFilenameAsIdentifier(StringRef Name,
   return Name;
 }
 
+/// \brief Determine whether the given file name is the name of a builtin
+/// header, supplied by Clang to replace, override, or augment existing system
+/// headers.
+static bool isBuiltinHeader(StringRef FileName) {
+  return llvm::StringSwitch<bool>(FileName)
+           .Case("float.h", true)
+           .Case("iso646.h", true)
+           .Case("limits.h", true)
+           .Case("stdalign.h", true)
+           .Case("stdarg.h", true)
+           .Case("stdbool.h", true)
+           .Case("stddef.h", true)
+           .Case("stdint.h", true)
+           .Case("tgmath.h", true)
+           .Case("unwind.h", true)
+           .Default(false);
+}
+
 Module *ModuleMap::findModuleForHeader(const FileEntry *File) {
   HeadersMap::iterator Known = Headers.find(File);
   if (Known != Headers.end()) {
@@ -158,6 +176,25 @@ Module *ModuleMap::findModuleForHeader(const FileEntry *File) {
 
     return Known->second.getModule();
   }
+
+  // If we've found a builtin header within Clang's builtin include directory,
+  // load all of the module maps to see if it will get associated with a
+  // specific module (e.g., in /usr/include).
+  if (File->getDir() == BuiltinIncludeDir &&
+      isBuiltinHeader(llvm::sys::path::filename(File->getName()))) {
+    SmallVector<Module *, 4> AllModules;
+    HeaderInfo.collectAllModules(AllModules);
+
+    // Check again.
+    Known = Headers.find(File);
+    if (Known != Headers.end()) {
+      // If a header is not available, don't report that it maps to anything.
+      if (!Known->second.isAvailable())
+        return 0;
+
+      return Known->second.getModule();
+    }
+  }
   
   const DirectoryEntry *Dir = File->getDir();
   SmallVector<const DirectoryEntry *, 2> SkippedDirs;
@@ -1266,24 +1303,6 @@ static void appendSubframeworkPaths(Module *Mod,
   }
 }
 
-/// \brief Determine whether the given file name is the name of a builtin
-/// header, supplied by Clang to replace, override, or augment existing system
-/// headers.
-static bool isBuiltinHeader(StringRef FileName) {
-  return llvm::StringSwitch<bool>(FileName)
-      .Case("float.h", true)
-      .Case("iso646.h", true)
-      .Case("limits.h", true)
-      .Case("stdalign.h", true)
-      .Case("stdarg.h", true)
-      .Case("stdbool.h", true)
-      .Case("stddef.h", true)
-      .Case("stdint.h", true)
-      .Case("tgmath.h", true)
-      .Case("unwind.h", true)
-      .Default(false);
-}
-
 /// \brief Parse a header declaration.
 ///
 ///   header-declaration:

diff --git a/test/Modules/Inputs/System/usr/include/dbl_max.h b/test/Modules/Inputs/System/usr/include/dbl_max.h
new file mode 100644 (file)
index 0000000..9a020d1
--- /dev/null
+++ b/test/Modules/Inputs/System/usr/include/dbl_max.h
@@ -0,0 +1 @@
+#define DBL_MAX __DBL_MAX__

diff --git a/test/Modules/Inputs/System/usr/include/module.map b/test/Modules/Inputs/System/usr/include/module.map
index 884b59c80cd0bd8f222eaf1ef411d7576ddfe0f0..9b2f3af2bacee53ef9f8fdfe64414f3af94bcc82 100644 (file)
--- a/test/Modules/Inputs/System/usr/include/module.map
+++ b/test/Modules/Inputs/System/usr/include/module.map
@@ -19,3 +19,14 @@ module cstd [system] {
     header "stdint.h"
   }
 }
+
+module other_constants {
+  explicit module dbl_max {
+    header "dbl_max.h"
+  }
+}
+
+module uses_other_constants {
+  header "uses_other_constants.h"
+  export *
+}

diff --git a/test/Modules/Inputs/System/usr/include/uses_other_constants.h b/test/Modules/Inputs/System/usr/include/uses_other_constants.h
new file mode 100644 (file)
index 0000000..f6d4cca
--- /dev/null
+++ b/test/Modules/Inputs/System/usr/include/uses_other_constants.h
@@ -0,0 +1,3 @@
+@import other_constants;
+#include <float.h>
+

diff --git a/test/Modules/cstd.m b/test/Modules/cstd.m
index 6d896a915579b19ffea1b3b7fb69166329bf2f93..3d1dcf38e33cd1853707244a91f3c066d7f1e6a3 100644 (file)
--- a/test/Modules/cstd.m
+++ b/test/Modules/cstd.m
@@ -1,6 +1,9 @@
 // RUN: rm -rf %t
 // RUN: %clang -fsyntax-only -isystem %S/Inputs/System/usr/include -fmodules -fmodules-cache-path=%t -D__need_wint_t -Werror=implicit-function-declaration %s
 
+@import uses_other_constants;
+const double other_value = DBL_MAX;
+
 // Supplied by compiler, but referenced from the "/usr/include" module map.
 @import cstd.float_constants;
 
@@ -16,7 +19,7 @@ void test_fprintf(FILE *file) {
 // Supplied by compiler, which forwards to the "/usr/include" version.
 @import cstd.stdint;
 
-my_awesome_nonstandard_integer_type value;
+my_awesome_nonstandard_integer_type value2;
 
 // Supplied by the compiler; that version wins.
 @import cstd.stdbool;
@@ -25,5 +28,3 @@ my_awesome_nonstandard_integer_type value;
 #  error "bool was not defined!"
 #endif
 
-
-