Support: chunk writing on Linux

This is a workaround for large file writes.  It has been witnessed that
write(2) failing with EINVAL (22) due to a large value (>2G).  Thanks to
James Knight for the help with coming up with a sane test case.

llvm-svn: 305846

1 files changed, 6 insertions, 0 deletions

diff --git a/llvm/unittests/Support/CommandLineTest.cpp b/llvm/unittests/Support/CommandLineTest.cpp
index f9dc393..660df11 100644
--- a/llvm/unittests/Support/CommandLineTest.cpp
+++ b/llvm/unittests/Support/CommandLineTest.cpp
@@ -13,6 +13,7 @@
 #include "llvm/Config/config.h"
 #include "llvm/Support/FileSystem.h"
 #include "llvm/Support/Path.h"
+#include "llvm/Support/Program.h"
 #include "llvm/Support/StringSaver.h"
 #include "gtest/gtest.h"
 #include <fstream>
@@ -546,6 +547,11 @@ TEST(CommandLineTest, GetRegisteredSubcommands) {
   }
 }
 
+TEST(CommandLineTest, ArgumentLimit) {
+  std::string args(32 * 4096, 'a');
+  EXPECT_FALSE(llvm::sys::commandLineFitsWithinSystemLimits("cl", args.data()));
+}
+
 TEST(CommandLineTest, ResponseFiles) {
   llvm::SmallString<128> TestDir;
   std::error_code EC =