From b52241e381d0f3bf15ff37c4151b53b42853fb5d Mon Sep 17 00:00:00 2001
From: Allan Shortlidge <shortlidge@apple.com>
Date: Mon, 26 Aug 2024 16:29:40 -0700
Subject: [PATCH] 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.
---
 lib/FrontendTool/FrontendTool.cpp      | 18 ++++++++++++------
 test/Frontend/crash-whole-module.swift | 14 ++++++++++++++
 test/Frontend/crash.swift              | 18 ++++++++++++++----
 3 files changed, 40 insertions(+), 10 deletions(-)
 create mode 100644 test/Frontend/crash-whole-module.swift

diff --git a/lib/FrontendTool/FrontendTool.cpp b/lib/FrontendTool/FrontendTool.cpp
index d23a6c0afcc2e..8d8f579640d92 100644
--- a/lib/FrontendTool/FrontendTool.cpp
+++ b/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) {
diff --git a/test/Frontend/crash-whole-module.swift b/test/Frontend/crash-whole-module.swift
new file mode 100644
index 0000000000000..2bac92594787a
--- /dev/null
+++ b/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()
diff --git a/test/Frontend/crash.swift b/test/Frontend/crash.swift
index 476dff6089332..30374acd4b130 100644
--- a/test/Frontend/crash.swift
+++ b/test/Frontend/crash.swift
@@ -1,5 +1,10 @@
-// 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
@@ -7,9 +12,14 @@
 // 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