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

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