Allow some differences between the predefines buffer used to build a

PCH file and the predefines buffer used when including the PCH
file. We (explicitly) detect conflicting macro definitions (rejecting
the PCH file) and about missing macro definitions (they'll be
automatically pulled from the PCH file anyway).

We're missing some checking to make sure that new macro definitions
won't have any impact on the PCH file itself (e.g., #define'ing an
identifier that the PCH file used).

llvm-svn: 70316

2 files changed, 19 insertions, 0 deletions

diff --git a/clang/test/PCH/fuzzy-pch.c b/clang/test/PCH/fuzzy-pch.c
new file mode 100644
index 00000000000..ce4634d756b
--- /dev/null
+++ b/clang/test/PCH/fuzzy-pch.c
@@ -0,0 +1,17 @@
+// Test with pch.
+// RUN: clang-cc -emit-pch -DFOO -o %t %S/variables.h &&
+// RUN: clang-cc -DBAR=int -include-pch %t -fsyntax-only -pedantic %s 
+
+BAR bar = 17;
+
+#ifndef FOO
+#  error FOO was not defined
+#endif
+
+#if FOO != 1
+#  error FOO has the wrong definition
+#endif
+
+#ifndef BAR
+#  error BAR was not defined
+#endif
diff --git a/clang/test/PCH/fuzzy-pch.h b/clang/test/PCH/fuzzy-pch.h
new file mode 100644
index 00000000000..9eb1005ce44
--- /dev/null
+++ b/clang/test/PCH/fuzzy-pch.h
@@ -0,0 +1,2 @@
+// Header for PCH test fuzzy-pch.c
+void f(int X);