[driver/sourcekit] Avoid creating temporary output files in TMPDIR

When producing frontend arguments for sourcekitd, force the output mode
to -typecheck so that we do not create any temporary output files in the
driver. Previously, any sourcekitd operation that created a compiler
invocation would create 0-sized .o file inside $TMPDIR that would never
be cleaned up.

The new swift-driver project handles temporaries much better as
VirtualPath, and should not need this approach.

rdar://62366123

Author: benlangmuir

include/swift/Driver/FrontendUtil.h

@@ -33,14 +33,18 @@ namespace driver {
 /// \param Action Called with the list of frontend arguments if there were no
 /// errors in processing \p ArgList. This is a callback rather than a return
 /// value to avoid copying the arguments more than necessary.
+/// \param ForceNoOutputs If true, override the output mode to "-typecheck" and
+/// produce no outputs. For example, this disables "-emit-module" and "-c" and
+/// prevents the creation of temporary files.
 ///
 /// \returns True on error, or if \p Action returns true.
 ///
 /// \note This function is not intended to create invocations which are
 /// suitable for use in REPL or immediate modes.
 bool getSingleFrontendInvocationFromDriverArguments(
     ArrayRef<const char *> ArgList, DiagnosticEngine &Diags,
-    llvm::function_ref<bool(ArrayRef<const char *> FrontendArgs)> Action);
+    llvm::function_ref<bool(ArrayRef<const char *> FrontendArgs)> Action,
+    bool ForceNoOutputs = false);
 
 } // end namespace driver
 } // end namespace swift

lib/Driver/FrontendUtil.cpp

@@ -25,7 +25,8 @@ using namespace swift::driver;
 
 bool swift::driver::getSingleFrontendInvocationFromDriverArguments(
     ArrayRef<const char *> Argv, DiagnosticEngine &Diags,
-    llvm::function_ref<bool(ArrayRef<const char *> FrontendArgs)> Action) {
+    llvm::function_ref<bool(ArrayRef<const char *> FrontendArgs)> Action,
+    bool ForceNoOutputs) {
   SmallVector<const char *, 16> Args;
   Args.push_back("<swiftc>"); // FIXME: Remove dummy argument.
   Args.insert(Args.end(), Argv.begin(), Argv.end());
@@ -57,6 +58,25 @@ bool swift::driver::getSingleFrontendInvocationFromDriverArguments(
   if (Diags.hadAnyError())
     return true;
 
+  if (ForceNoOutputs) {
+    // Clear existing output modes.
+    ArgList->eraseArg(options::OPT_modes_Group);
+    // Disable other output options that conflict with -typecheck.
+    ArgList->eraseArg(options::OPT_emit_module);
+    ArgList->eraseArg(options::OPT_emit_module_path);
+    ArgList->eraseArg(options::OPT_emit_module_source_info_path);
+    ArgList->eraseArg(options::OPT_emit_module_interface);
+    ArgList->eraseArg(options::OPT_emit_module_interface_path);
+    ArgList->eraseArg(options::OPT_emit_objc_header);
+    ArgList->eraseArg(options::OPT_emit_objc_header_path);
+
+    unsigned index = ArgList->MakeIndex("-typecheck");
+    // Takes ownership of the Arg.
+    ArgList->append(new llvm::opt::Arg(
+        TheDriver.getOpts().getOption(options::OPT_typecheck),
+        ArgList->getArgString(index), index));
+  }
+
   std::unique_ptr<ToolChain> TC = TheDriver.buildToolChain(*ArgList);
   if (Diags.hadAnyError())
     return true;

test/SourceKit/Misc/no-driver-outputs.swift

@@ -0,0 +1,29 @@
+// REQUIRES: shell
+
+// RUN: %empty-directory(%t)
+// RUN: env TMPDIR=%t __XPC_TMPDIR=%t %sourcekitd-test -req=syntax-map %s 
+// RUN: ls %t/ | count 0
+
+// RUN: %empty-directory(%t)
+// RUN: env TMPDIR=%t __XPC_TMPDIR=%t %sourcekitd-test -req=syntax-map %s -- %s
+// RUN: ls %t/ | count 0
+
+// RUN: %empty-directory(%t)
+// RUN: env TMPDIR=%t __XPC_TMPDIR=%t %sourcekitd-test -req=syntax-map %s -- %s -c -o %t/foo.o
+// RUN: ls %t/ | count 0
+
+// RUN: %empty-directory(%t)
+// RUN: env TMPDIR=%t __XPC_TMPDIR=%t %sourcekitd-test -req=sema %s -- %s
+// RUN: ls %t/ | count 0
+
+// RUN: %empty-directory(%t)
+// RUN: env TMPDIR=%t __XPC_TMPDIR=%t %sourcekitd-test -req=sema %s -- %s -c -o %t/foo.o
+// RUN: ls %t/ | count 0
+
+// RUN: %empty-directory(%t)
+// RUN: env TMPDIR=%t __XPC_TMPDIR=%t %sourcekitd-test -req=sema %s -- %s -emit-module -module-name main -emit-module-path %t/main.swiftmodule -emit-module-interface -enable-library-evolution -emit-module-interface-path %t/main.swiftinterface -emit-objc-header -emit-objc-header-path %t/main.h -c -o %t/foo.o
+// RUN: ls %t/ | count 0
+
+// RUN: %empty-directory(%t)
+// RUN: env TMPDIR=%t __XPC_TMPDIR=%t %sourcekitd-test -req=sema %s -- %s -emit-module -module-name main -emit-module-path %t/main.swiftmodule -emit-executable -o %t/foo
+// RUN: ls %t/ | count 0

tools/SourceKit/lib/SwiftLang/SwiftASTManager.cpp

@@ -507,7 +507,7 @@ bool SwiftASTManager::initCompilerInvocation(
   bool HadError = driver::getSingleFrontendInvocationFromDriverArguments(
       Args, Diags, [&](ArrayRef<const char *> FrontendArgs) {
     return Invocation.parseArgs(FrontendArgs, Diags);
-  });
+  }, /*ForceNoOutputs=*/true);
 
   // Remove the StreamDiagConsumer as it's no longer needed.
   Diags.removeConsumer(DiagConsumer);