<rdar://problem/13615607> Include SDK version information in the module hash.

This is a Darwin-SDK-specific hash criteria used to identify a
particular SDK without having to hash the contents of all of its
headers. If other platforms have such versioned files, we should add
those checks here.


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@179346 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 49 insertions, 0 deletions

diff --git a/lib/Frontend/CompilerInvocation.cpp b/lib/Frontend/CompilerInvocation.cpp
index 42774f3a6a..c8ccffa91d 100644
--- a/lib/Frontend/CompilerInvocation.cpp
+++ b/lib/Frontend/CompilerInvocation.cpp
@@ -29,6 +29,7 @@
 #include "llvm/Support/ErrorHandling.h"
 #include "llvm/Support/Host.h"
 #include "llvm/Support/Path.h"
+#include "llvm/Support/system_error.h"
 using namespace clang;
 
 //===----------------------------------------------------------------------===//
@@ -1696,5 +1697,21 @@ std::string CompilerInvocation::getModuleHash() const {
                       hsOpts.UseStandardCXXIncludes,
                       hsOpts.UseLibcxx);
 
+  // Darwin-specific hack: if we have a sysroot, use the contents of
+  //   $sysroot/System/Library/CoreServices/SystemVersion.plist
+  // as part of the module hash.
+  if (!hsOpts.Sysroot.empty()) {
+    llvm::OwningPtr<llvm::MemoryBuffer> buffer;
+    SmallString<128> systemVersionFile;
+    systemVersionFile += hsOpts.Sysroot;
+    llvm::sys::path::append(systemVersionFile, "System");
+    llvm::sys::path::append(systemVersionFile, "Library");
+    llvm::sys::path::append(systemVersionFile, "CoreServices");
+    llvm::sys::path::append(systemVersionFile, "SystemVersion.plist");
+    if (!llvm::MemoryBuffer::getFile(systemVersionFile, buffer)) {
+      code = hash_combine(code, buffer.get()->getBuffer());
+    }
+  }
+
   return llvm::APInt(64, code).toString(36, /*Signed=*/false);
 }
diff --git a/test/Modules/system_version.m b/test/Modules/system_version.m
new file mode 100644
index 0000000000..2beddf4e1d
--- /dev/null
+++ b/test/Modules/system_version.m
@@ -0,0 +1,32 @@
+// Test checking that we're hashing a system version file in the
+// module hash.
+// REQUIRES: shell
+
+// First, build a system root.
+// RUN: rm -rf %t
+// RUN: mkdir -p %t/usr/include
+// RUN: cp %S/Inputs/Modified/A.h %t/usr/include
+// RUN: cp %S/Inputs/Modified/B.h %t/usr/include
+// RUN: cp %S/Inputs/Modified/module.map %t/usr/include
+
+// Run once with no system version file. We should end up with one module.
+// RUN: %clang_cc1 -fmodules-cache-path=%t/cache -fmodules -isysroot %t %s -verify
+// RUN: ls -R %t | grep -c ModA.pcm| grep 1
+
+// Add a system version file and run again. We should now have two
+// module variants.
+// RUN: mkdir -p %t/System/Library/CoreServices
+// RUN: echo "hello" > %t/System/Library/CoreServices/SystemVersion.plist
+// RUN: %clang_cc1 -fmodules-cache-path=%t/cache -fmodules -isysroot %t %s -verify
+// RUN: ls -R %t | grep -c ModA.pcm| grep 2
+
+// Change the system version file and run again. We should now have three
+// module variants.
+// RUN: mkdir -p %t/System/Library/CoreServices
+// RUN: echo "modules" > %t/System/Library/CoreServices/SystemVersion.plist
+// RUN: %clang_cc1 -fmodules-cache-path=%t/cache -fmodules -isysroot %t %s -verify
+// RUN: ls -R %t | grep -c ModA.pcm| grep 3
+
+// expected-no-diagnostics
+@import ModA;
+