Fail early if an output file is not writable

Fixes https://bugs.llvm.org/show_bug.cgi?id=36478

Differential Revision: https://reviews.llvm.org/D43664

llvm-svn: 355834

lld/COFF/Driver.cpp

@@ -18,6 +18,7 @@
 #include "lld/Common/Args.h"
 #include "lld/Common/Driver.h"
 #include "lld/Common/ErrorHandler.h"
+#include "lld/Common/Filesystem.h"
 #include "lld/Common/Memory.h"
 #include "lld/Common/Threads.h"
 #include "lld/Common/Timer.h"
@@ -1525,6 +1526,12 @@ void LinkerDriver::link(ArrayRef<const char *> ArgsArr) {
         getOutputPath((*Args.filtered(OPT_INPUT).begin())->getValue());
   }
 
+  // Fail early if an output file is not writable.
+  if (auto E = tryCreateFile(Config->OutputFile)) {
+    error("cannot open output file " + Config->OutputFile + ": " + E.message());
+    return;
+  }
+
   if (ShouldCreatePDB) {
     // Put the PDB next to the image if no /pdb flag was passed.
     if (Config->PDBPath.empty()) {

lld/Common/CMakeLists.txt

@@ -30,6 +30,7 @@ set_property(SOURCE Version.cpp APPEND PROPERTY
 add_lld_library(lldCommon
   Args.cpp
   ErrorHandler.cpp
+  Filesystem.cpp
   Memory.cpp
   Reproduce.cpp
   Strings.cpp

lld/Common/Filesystem.cpp

@@ -10,8 +10,7 @@
 //
 //===----------------------------------------------------------------------===//
 
-#include "Filesystem.h"
-#include "Config.h"
+#include "lld/Common/Filesystem.h"
 #include "lld/Common/Threads.h"
 #include "llvm/Config/llvm-config.h"
 #include "llvm/Support/FileOutputBuffer.h"
@@ -22,9 +21,7 @@
 #include <thread>
 
 using namespace llvm;
-
 using namespace lld;
-using namespace lld::elf;
 
 // Removes a given file asynchronously. This is a performance hack,
 // so remove this when operating systems are improved.
@@ -41,7 +38,7 @@ using namespace lld::elf;
 //
 // This function spawns a background thread to remove the file.
 // The calling thread returns almost immediately.
-void elf::unlinkAsync(StringRef Path) {
+void lld::unlinkAsync(StringRef Path) {
 // Removing a file is async on windows.
 #if defined(_WIN32)
   sys::fs::remove(Path);
@@ -93,7 +90,7 @@ void elf::unlinkAsync(StringRef Path) {
 // FileOutputBuffer doesn't touch a desitnation file until commit()
 // is called. We use that class without calling commit() to predict
 // if the given file is writable.
-std::error_code elf::tryCreateFile(StringRef Path) {
+std::error_code lld::tryCreateFile(StringRef Path) {
   if (Path.empty())
     return std::error_code();
   if (Path == "-")

lld/ELF/CMakeLists.txt

@@ -27,7 +27,6 @@ add_lld_library(lldELF
   Driver.cpp
   DriverUtils.cpp
   EhFrame.cpp
-  Filesystem.cpp
   ICF.cpp
   InputFiles.cpp
   InputSection.cpp

lld/ELF/Driver.cpp

@@ -24,7 +24,6 @@
 
 #include "Driver.h"
 #include "Config.h"
-#include "Filesystem.h"
 #include "ICF.h"
 #include "InputFiles.h"
 #include "InputSection.h"
@@ -40,6 +39,7 @@
 #include "lld/Common/Args.h"
 #include "lld/Common/Driver.h"
 #include "lld/Common/ErrorHandler.h"
+#include "lld/Common/Filesystem.h"
 #include "lld/Common/Memory.h"
 #include "lld/Common/Strings.h"
 #include "lld/Common/TargetOptionsCommandFlags.h"

lld/ELF/Writer.cpp

@@ -10,7 +10,6 @@
 #include "AArch64ErrataFix.h"
 #include "CallGraphSort.h"
 #include "Config.h"
-#include "Filesystem.h"
 #include "LinkerScript.h"
 #include "MapFile.h"
 #include "OutputSections.h"
@@ -19,6 +18,7 @@
 #include "Symbols.h"
 #include "SyntheticSections.h"
 #include "Target.h"
+#include "lld/Common/Filesystem.h"
 #include "lld/Common/Memory.h"
 #include "lld/Common/Strings.h"
 #include "lld/Common/Threads.h"

lld/include/lld/Common/Filesystem.h

@@ -6,17 +6,15 @@
 //
 //===----------------------------------------------------------------------===//
 
-#ifndef LLD_ELF_FILESYSTEM_H
-#define LLD_ELF_FILESYSTEM_H
+#ifndef LLD_FILESYSTEM_H
+#define LLD_FILESYSTEM_H
 
 #include "lld/Common/LLVM.h"
 #include <system_error>
 
 namespace lld {
-namespace elf {
 void unlinkAsync(StringRef Path);
 std::error_code tryCreateFile(StringRef Path);
-} // namespace elf
 } // namespace lld
 
 #endif

lld/test/COFF/driver.test

@@ -15,3 +15,7 @@ LIBHELP: OVERVIEW: LLVM Lib
 
 # RUN: not lld-link /WX /lib 2>&1 | FileCheck -check-prefix=LIBBAD %s
 LIBBAD: ignoring /lib since it's not the first argument
+
+# RUN: yaml2obj < %p/Inputs/hello32.yaml > %t.obj
+# RUN: not lld-link /out:/ %t.obj 2>&1 | FileCheck -check-prefix=DIR %s
+DIR: cannot open output file