[Modules] Early-exit if ReadOptionsBlock fails to avoid crashing

If we didn't tell ReadOptionsBlock to allow failures then we can't
assume that the stream is not in the middle of a block if it returns
out-of-date. This was causing a crash when we tried to continue reading.

Also, it's just generally a good idea to early-exit if we're doing
implicit module builds, since we will want to immediately rebuild this
module anyway and there's no reason to waste time continuing after
failure.

rdar://problem/24114938

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@260563 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Serialization/ASTReader.cpp b/lib/Serialization/ASTReader.cpp
index b2f59d1fa6c91601452387be3571506eddd1af57..ac78da26140503108df358157728090d0d5aa9d6 100644 (file)
--- a/lib/Serialization/ASTReader.cpp
+++ b/lib/Serialization/ASTReader.cpp
@@ -2269,9 +2269,10 @@ ASTReader::ReadControlBlock(ModuleFile &F,
               (AllowConfigurationMismatch && Result == ConfigurationMismatch))
             Result = Success;
 
-          // If we've diagnosed a problem, we're done.
-          if (Result != Success &&
-              isDiagnosedResult(Result, ClientLoadCapabilities))
+          // If we can't load the module, exit early since we likely
+          // will rebuild the module anyway. The stream may be in the
+          // middle of a block.
+          if (Result != Success)
             return Result;
         } else if (Stream.SkipBlock()) {
           Error("malformed block record in AST file");

diff --git a/test/Modules/implicit-build-config-out-of-date.m b/test/Modules/implicit-build-config-out-of-date.m
new file mode 100644 (file)
index 0000000..c8c02ff
--- /dev/null
+++ b/test/Modules/implicit-build-config-out-of-date.m
@@ -0,0 +1,6 @@
+// RUN: rm -rf %t
+// Use -DA=0 so that there is at least one preprocessor option serialized after the diagnostic options.
+// RUN: %clang_cc1 -fmodules -fmodules-cache-path=%t -fimplicit-module-maps -I %S/Inputs %s -DA=0 -Rmodule-build -verify
+// RUN: %clang_cc1 -fmodules -fmodules-cache-path=%t -fimplicit-module-maps -I %S/Inputs %s -DA=0 -Werror -Rmodule-build -verify
+
+@import category_top; // expected-remark {{building module}} expected-remark {{finished building}}