Frontend: For whole module compiles, omit filelists from stack dumps.

For batch compile jobs, it's helpful to see which files are considered primary
and that was the original reason why filelist contents were printed in compiler
crash stack dumps. However, for whole module compile jobs, the contents of the
filelist is uninteresting (it's just all the files in the module) and can be
hundreds or thousands of lines long so it often causes important information to
be trimmed from stack dumps received in reproducers.

Author: tshortli

lib/FrontendTool/FrontendTool.cpp

@@ -1986,12 +1986,18 @@ int swift::performFrontend(ArrayRef<const char *> Args,
   auto configurationFileStackTraces =
       std::make_unique<std::optional<PrettyStackTraceFileContents>[]>(
           configurationFileBuffers.size());
-  for_each(configurationFileBuffers.begin(), configurationFileBuffers.end(),
-           &configurationFileStackTraces[0],
-           [](const std::unique_ptr<llvm::MemoryBuffer> &buffer,
-              std::optional<PrettyStackTraceFileContents> &trace) {
-             trace.emplace(*buffer);
-           });
+
+  // If the compile is a whole module job, then the contents of the filelist
+  // is every file in the module, which is not very interesting and could be
+  // hundreds or thousands of lines. Skip dumping this output in that case.
+  if (!Invocation.getFrontendOptions().InputsAndOutputs.isWholeModule()) {
+    for_each(configurationFileBuffers.begin(), configurationFileBuffers.end(),
+             &configurationFileStackTraces[0],
+             [](const std::unique_ptr<llvm::MemoryBuffer> &buffer,
+                std::optional<PrettyStackTraceFileContents> &trace) {
+               trace.emplace(*buffer);
+             });
+  }
 
   // The compiler invocation is now fully configured; notify our observer.
   if (observer) {

test/Frontend/crash-whole-module.swift

@@ -0,0 +1,14 @@
+// RUN: %empty-directory(%t)
+// RUN: echo %s > %t/filelist.txt
+// RUN: not --crash %target-swift-frontend -typecheck -debug-crash-after-parse -filelist %t/filelist.txt 2>&1 | %FileCheck %s
+
+// CHECK-LABEL: Stack dump
+// CHECK-NEXT: Program arguments: {{.*swift(-frontend)?(c?)(\.exe)?}}
+// CHECK-NEXT: Swift version
+// CHECK-NEXT: Compiling with effective version
+
+// Filelist contents should be omitted since this is a whole-module compile.
+// CHECK-NOT:  Contents of
+
+func anchor() {}
+anchor()

test/Frontend/crash.swift

@@ -1,15 +1,25 @@
-// RUN: echo %s > %t.filelist.txt
-// RUN: not --crash %target-swift-frontend -typecheck -debug-crash-after-parse -filelist %t.filelist.txt 2>&1 | %FileCheck %s
+// RUN: %empty-directory(%t)
+// RUN: echo %s > %t/primary.filelist.txt
+// RUN: echo "" > %t/empty.swift
+// RUN: echo "%t/empty.swift" > %t/all.filelist.txt
+// RUN: echo %s >> %t/all.filelist.txt
+
+// RUN: not --crash %target-swift-frontend -typecheck -debug-crash-after-parse -primary-filelist %t/primary.filelist.txt -filelist %t/all.filelist.txt 2>&1 | %FileCheck %s
 
 // Check that we see the contents of the input file list in the crash log.
 // CHECK-NOT: while allowing modules with compiler errors
 // CHECK-LABEL: Stack dump
 // CHECK-NEXT: Program arguments: {{.*swift(-frontend)?(c?)(\.exe)?}}
 // CHECK-NEXT: Swift version
 // CHECK-NEXT: Compiling with effective version
-// CHECK-NEXT: Contents of {{.*}}.filelist.txt:
+// CHECK-NEXT: Contents of {{.*}}/all.filelist.txt:
+// CHECK-NEXT: ---
+// CHECK-NEXT: {{[\\/]}}empty.swift{{$}}
+// CHECK-NEXT: {{[\\/]}}crash.swift{{$}}
+// CHECK-NEXT: ---
+// CHECK-NEXT: Contents of {{.*}}/primary.filelist.txt:
 // CHECK-NEXT: ---
-// CHECK-NEXT: test{{[\\/]}}Frontend{{[\\/]}}crash.swift{{$}}
+// CHECK-NEXT: {{[\\/]}}crash.swift{{$}}
 // CHECK-NEXT: ---
 
 // RUN: not --crash %target-swift-frontend -typecheck -debug-crash-after-parse -experimental-allow-module-with-compiler-errors %s 2>&1 | %FileCheck -check-prefix CHECK-ALLOW %s