[llvm] r305846 - Support: chunk writing on Linux
Saleem Abdulrasool via llvm-commits
llvm-commits at lists.llvm.org
Tue Jun 20 13:51:51 PDT 2017
Author: compnerd
Date: Tue Jun 20 15:51:51 2017
New Revision: 305846
URL: http://llvm.org/viewvc/llvm-project?rev=305846&view=rev
Log:
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.
Modified:
llvm/trunk/lib/Support/Unix/Program.inc
llvm/trunk/lib/Support/raw_ostream.cpp
llvm/trunk/unittests/Support/CommandLineTest.cpp
Modified: llvm/trunk/lib/Support/Unix/Program.inc
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Support/Unix/Program.inc?rev=305846&r1=305845&r2=305846&view=diff
==============================================================================
--- llvm/trunk/lib/Support/Unix/Program.inc (original)
+++ llvm/trunk/lib/Support/Unix/Program.inc Tue Jun 20 15:51:51 2017
@@ -449,11 +449,22 @@ bool llvm::sys::commandLineFitsWithinSys
size_t ArgLength = Program.size() + 1;
for (ArrayRef<const char*>::iterator I = Args.begin(), E = Args.end();
I != E; ++I) {
- ArgLength += strlen(*I) + 1;
+ size_t length = strlen(*I);
+
+ // Ensure that we do not exceed the MAX_ARG_STRLEN constant on Linux, which
+ // does not have a constant unlike what the man pages would have you
+ // believe. Since this limit is pretty high, perform the check
+ // unconditionally rather than trying to be aggressive and limiting it to
+ // Linux only.
+ if (length >= (32 * 4096))
+ return false;
+
+ ArgLength += length + 1;
if (ArgLength > size_t(HalfArgMax)) {
return false;
}
}
+
return true;
}
}
Modified: llvm/trunk/lib/Support/raw_ostream.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Support/raw_ostream.cpp?rev=305846&r1=305845&r2=305846&view=diff
==============================================================================
--- llvm/trunk/lib/Support/raw_ostream.cpp (original)
+++ llvm/trunk/lib/Support/raw_ostream.cpp Tue Jun 20 15:51:51 2017
@@ -548,7 +548,11 @@ void raw_fd_ostream::write_impl(const ch
pos += Size;
#ifndef LLVM_ON_WIN32
+#if defined(__linux__)
+ bool ShouldWriteInChunks = true;
+#else
bool ShouldWriteInChunks = false;
+#endif
#else
// Writing a large size of output to Windows console returns ENOMEM. It seems
// that, prior to Windows 8, WriteFile() is redirecting to WriteConsole(), and
Modified: llvm/trunk/unittests/Support/CommandLineTest.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/unittests/Support/CommandLineTest.cpp?rev=305846&r1=305845&r2=305846&view=diff
==============================================================================
--- llvm/trunk/unittests/Support/CommandLineTest.cpp (original)
+++ llvm/trunk/unittests/Support/CommandLineTest.cpp Tue Jun 20 15:51:51 2017
@@ -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, GetRegisteredSubco
}
}
+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 =
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