From 67cec8c3523c5e934d03922badba5aa253e68e6c Mon Sep 17 00:00:00 2001
From: Justin Lebar <jlebar@google.com>
Date: Wed, 24 Feb 2016 21:49:28 +0000
Subject: [PATCH] Bail on compilation as soon as a job fails.

Summary:
(Re-land of r260448, which was reverted in r260522 due to a test failure
in Driver/output-file-cleanup.c that only showed up in fresh builds.)

Previously we attempted to be smart; if one job failed, we'd run all
jobs that didn't depend on the failing job.

Problem is, this doesn't work well for e.g. CUDA compilation without
-save-temps.  In this case, the device-side and host-side Assemble
actions (which actually are responsible for preprocess, compile,
backend, and assemble, since we're not saving temps) are necessarily
distinct.  So our clever heuristic doesn't help us, and we repeat every
error message once for host and once for each device arch.

The main effect of this change, other than fixing CUDA, is that if you
pass multiple cc files to one instance of clang and you get a compile
error, we'll stop when the first cc1 job fails.

Reviewers: echristo

Subscribers: cfe-commits, jhen, echristo, tra, rafael

Differential Revision: http://reviews.llvm.org/D17217

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@261774 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Driver/Compilation.cpp        | 38 +++++++------------------------
 test/Driver/output-file-cleanup.c |  7 ++++--
 2 files changed, 13 insertions(+), 32 deletions(-)

diff --git a/lib/Driver/Compilation.cpp b/lib/Driver/Compilation.cpp
index 71bccfa92d..b24d38161a 100644
--- a/lib/Driver/Compilation.cpp
+++ b/lib/Driver/Compilation.cpp
@@ -163,39 +163,17 @@ int Compilation::ExecuteCommand(const Command &C,
   return ExecutionFailed ? 1 : Res;
 }
 
-typedef SmallVectorImpl< std::pair<int, const Command *> > FailingCommandList;
-
-static bool ActionFailed(const Action *A,
-                         const FailingCommandList &FailingCommands) {
-
-  if (FailingCommands.empty())
-    return false;
-
-  for (FailingCommandList::const_iterator CI = FailingCommands.begin(),
-         CE = FailingCommands.end(); CI != CE; ++CI)
-    if (A == &(CI->second->getSource()))
-      return true;
-
-  for (const Action *AI : A->inputs())
-    if (ActionFailed(AI, FailingCommands))
-      return true;
-
-  return false;
-}
-
-static bool InputsOk(const Command &C,
-                     const FailingCommandList &FailingCommands) {
-  return !ActionFailed(&C.getSource(), FailingCommands);
-}
-
-void Compilation::ExecuteJobs(const JobList &Jobs,
-                              FailingCommandList &FailingCommands) const {
+void Compilation::ExecuteJobs(
+    const JobList &Jobs,
+    SmallVectorImpl<std::pair<int, const Command *>> &FailingCommands) const {
   for (const auto &Job : Jobs) {
-    if (!InputsOk(Job, FailingCommands))
-      continue;
     const Command *FailingCommand = nullptr;
-    if (int Res = ExecuteCommand(Job, FailingCommand))
+    if (int Res = ExecuteCommand(Job, FailingCommand)) {
       FailingCommands.push_back(std::make_pair(Res, FailingCommand));
+      // Bail as soon as one command fails, so we don't output duplicate error
+      // messages if we die on e.g. the same file.
+      return;
+    }
   }
 }
 
diff --git a/test/Driver/output-file-cleanup.c b/test/Driver/output-file-cleanup.c
index e907bd3607..314af4d6d3 100644
--- a/test/Driver/output-file-cleanup.c
+++ b/test/Driver/output-file-cleanup.c
@@ -38,6 +38,9 @@ invalid C code
 // RUN: test -f %t1.s
 // RUN: test ! -f %t2.s
 
+// When given multiple .c files to compile, clang compiles them in order until
+// it hits an error, at which point it stops.
+//
 // RUN: touch %t1.c
 // RUN: echo "invalid C code" > %t2.c
 // RUN: touch %t3.c
@@ -46,6 +49,6 @@ invalid C code
 // RUN: cd %T && not %clang -S %t1.c %t2.c %t3.c %t4.c %t5.c
 // RUN: test -f %t1.s
 // RUN: test ! -f %t2.s
-// RUN: test -f %t3.s
+// RUN: test ! -f %t3.s
 // RUN: test ! -f %t4.s
-// RUN: test -f %t5.s
+// RUN: test ! -f %t5.s
-- 
2.50.1