clang-cl: implement /fallback mode
When this flag is enabled, clang-cl falls back to cl.exe if it
cannot compile the code itself for some reason.
The idea is to use this to help build projects that almost compile
with clang-cl, except for some files that can then be built with
the fallback mechanism.
Differential Revision: http://llvm-reviews.chandlerc.com/D1711
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@191034 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Driver/Job.cpp b/lib/Driver/Job.cpp
index 7df46d3..ee68e6f 100644
--- a/lib/Driver/Job.cpp
+++ b/lib/Driver/Job.cpp
@@ -126,6 +126,43 @@
/*memoryLimit*/ 0, ErrMsg, ExecutionFailed);
}
+FallbackCommand::FallbackCommand(const Action &Source_, const Tool &Creator_,
+ const char *Executable_,
+ const ArgStringList &Arguments_,
+ Command *Fallback_)
+ : Command(Source_, Creator_, Executable_, Arguments_), Fallback(Fallback_) {
+}
+
+void FallbackCommand::Print(raw_ostream &OS, const char *Terminator,
+ bool Quote, bool CrashReport) const {
+ Command::Print(OS, "", Quote, CrashReport);
+ OS << " ||";
+ Fallback->Print(OS, Terminator, Quote, CrashReport);
+}
+
+static bool ShouldFallback(int ExitCode) {
+ // FIXME: We really just want to fall back for internal errors, such
+ // as when some symbol cannot be mangled, when we should be able to
+ // parse something but can't, etc.
+ return ExitCode != 0;
+}
+
+int FallbackCommand::Execute(const StringRef **Redirects, std::string *ErrMsg,
+ bool *ExecutionFailed) const {
+ int PrimaryStatus = Command::Execute(Redirects, ErrMsg, ExecutionFailed);
+ if (!ShouldFallback(PrimaryStatus))
+ return PrimaryStatus;
+
+ // Clear ExecutionFailed and ErrMsg before falling back.
+ if (ErrMsg)
+ ErrMsg->clear();
+ if (ExecutionFailed)
+ *ExecutionFailed = false;
+
+ int SecondaryStatus = Fallback->Execute(Redirects, ErrMsg, ExecutionFailed);
+ return SecondaryStatus;
+}
+
JobList::JobList() : Job(JobListClass) {}
JobList::~JobList() {