Driver: Keep -isysroot flags in crash scripts if we're dumping a VFS

For crashes with a VFS (ie, with modules), the -isysroot flag is often
necessary to reproduce the crash. This is especially true if some
modules need to be rebuilt, since without the sysroot they'll try to
read headers that are outside of the VFS.

I find it likely that we should keep some of the other -i flags in
this case as well, but I haven't seen that come up in practice yet so
it seems better to be conservative.

llvm-svn: 231997

2 files changed, 9 insertions, 5 deletions

diff --git a/clang/lib/Driver/Job.cpp b/clang/lib/Driver/Job.cpp
index 66434cf7b01..6d18a41cad0 100644
--- a/clang/lib/Driver/Job.cpp
+++ b/clang/lib/Driver/Job.cpp
@@ -34,7 +34,7 @@ Command::Command(const Action &_Source, const Tool &_Creator,
       Executable(_Executable), Arguments(_Arguments),
       ResponseFile(nullptr) {}
 
-static int skipArgs(const char *Flag) {
+static int skipArgs(const char *Flag, bool HaveCrashVFS) {
   // These flags are all of the form -Flag <Arg> and are treated as two
   // arguments.  Therefore, we need to skip the flag and the next argument.
   bool Res = llvm::StringSwitch<bool>(Flag)
@@ -43,9 +43,11 @@ static int skipArgs(const char *Flag) {
     .Cases("-fdebug-compilation-dir", "-idirafter", true)
     .Cases("-include", "-include-pch", "-internal-isystem", true)
     .Cases("-internal-externc-isystem", "-iprefix", "-iwithprefix", true)
-    .Cases("-iwithprefixbefore", "-isysroot", "-isystem", "-iquote", true)
+    .Cases("-iwithprefixbefore", "-isystem", "-iquote", true)
     .Cases("-resource-dir", "-serialize-diagnostic-file", true)
     .Cases("-dwarf-debug-flags", "-ivfsoverlay", true)
+    // Some include flags shouldn't be skipped if we have a crash VFS
+    .Case("-isysroot", !HaveCrashVFS)
     .Default(false);
 
   // Match found.
@@ -164,11 +166,12 @@ void Command::Print(raw_ostream &OS, const char *Terminator, bool Quote,
       if (StringRef(Args[I]).equals("-main-file-name"))
         MainFilename = Args[I + 1];
 
+  bool HaveCrashVFS = CrashInfo && !CrashInfo->VFSPath.empty();
   for (size_t i = 0, e = Args.size(); i < e; ++i) {
     const char *const Arg = Args[i];
 
     if (CrashInfo) {
-      if (int Skip = skipArgs(Arg)) {
+      if (int Skip = skipArgs(Arg, HaveCrashVFS)) {
         i += Skip - 1;
         continue;
       } else if (llvm::sys::path::filename(Arg) == MainFilename &&
@@ -185,7 +188,7 @@ void Command::Print(raw_ostream &OS, const char *Terminator, bool Quote,
     PrintArg(OS, Arg, Quote);
   }
 
-  if (CrashInfo && !CrashInfo->VFSPath.empty()) {
+  if (CrashInfo && HaveCrashVFS) {
     OS << ' ';
     PrintArg(OS, "-ivfsoverlay", Quote);
     OS << ' ';
diff --git a/clang/test/Driver/crash-report-modules.m b/clang/test/Driver/crash-report-modules.m
index dab92311e71..66ebaa750dd 100644
--- a/clang/test/Driver/crash-report-modules.m
+++ b/clang/test/Driver/crash-report-modules.m
@@ -2,7 +2,7 @@
 // RUN: mkdir %t
 
 // RUN: not env FORCE_CLANG_DIAGNOSTICS_CRASH= TMPDIR=%t TEMP=%t TMP=%t \
-// RUN: %clang -fsyntax-only %s -I %S/Inputs/module                     \
+// RUN: %clang -fsyntax-only %s -I %S/Inputs/module -isysroot /tmp/     \
 // RUN: -fmodules -fmodules-cache-path=/tmp/ -DFOO=BAR 2>&1 | FileCheck %s
 
 // RUN: FileCheck --check-prefix=CHECKSRC %s -input-file %t/crash-report-*.m
@@ -28,6 +28,7 @@ const int x = MODULE_MACRO;
 // CHECKSH: # Crash reproducer
 // CHECKSH-NEXT: # Original command: {{.*$}}
 // CHECKSH-NEXT: "-cc1"
+// CHECKSH: "-isysroot" "/tmp/"
 // CHECKSH: "-D" "FOO=BAR"
 // CHECKSH-NOT: "-fmodules-cache-path=/tmp/"
 // CHECKSH: "crash-report-modules-{{[^ ]*}}.m"