[clang] Make -fcrash-diagnostics default configurable

[abrachet]

Summary

Folks may want to change the default for their distribution.

[MaskRay]

I'm concerned of adding more and more knobs which are difficult to maintain and make testsuite diverged and more difficult for a contributor to cover every combination.
This is exactly the thing that https://discourse.llvm.org/t/rfc-adding-a-default-file-location-to-config-file-support/63606/45 tries to tackle in a generic way and I encourage that you switch to it.

[abrachet]

In D135197#3834932, @MaskRay wrote:

I'm concerned of adding more and more knobs which are difficult to maintain and make testsuite diverged and more difficult for a contributor to cover every combination.
This is exactly the thing that https://discourse.llvm.org/t/rfc-adding-a-default-file-location-to-config-file-support/63606/45 tries to tackle in a generic way and I encourage that you switch to it.

Ah cool I wasn't following that thread, thanks.

clang/CMakeLists.txt

 if(CLANG_ENABLE_OPAQUE_POINTERS STREQUAL "DEFAULT")
   set(CLANG_ENABLE_OPAQUE_POINTERS_INTERNAL ON)
 elseif(CLANG_ENABLE_OPAQUE_POINTERS)
   set(CLANG_ENABLE_OPAQUE_POINTERS_INTERNAL ON)
 else()
   set(CLANG_ENABLE_OPAQUE_POINTERS_INTERNAL OFF)
 endif()
 
+set(CLANG_CRASH_DIAG_OFF 0)
+set(CLANG_CRASH_DIAG_COMPILER 1)
+set(CLANG_CRASH_DIAG_ALL 2)
+set(CLANG_CRASH_DIAG_DEFAULT ${CLANG_CRASH_DIAG_COMPILER})
+
+set(CLANG_DEFAULT_CRASH_DIAG_LEVEL CLANG_CRASH_DIAG_COMPILER CACHE STRING
+    "Specifies for which tools clang should perform crash reproduction. \
+    Use the CLANG_CRASH_DIAG_* variables. They mean, no diagnostics, \
+    only when the compiler crashes, and crashes from all possible tools \
+    respectively."
+    )
+
+if(${${CLANG_DEFAULT_CRASH_DIAG_LEVEL}} STREQUAL ${CLANG_CRASH_DIAG_DEFAULT})
+  set(CLANG_CRASH_DIAG_IS_DEFAULT 1)
+else()
+  set(CLANG_CRASH_DIAG_IS_DEFAULT 0)
+endif()
+
 # TODO: verify the values against LangStandards.def?
 set(CLANG_DEFAULT_STD_C "" CACHE STRING
   "Default standard to use for C/ObjC code (IDENT from LangStandards.def, empty for platform default)")
 set(CLANG_DEFAULT_STD_CXX "" CACHE STRING
   "Default standard to use for C++/ObjC++ code (IDENT from LangStandards.def, empty for platform default)")
 
 set(CLANG_DEFAULT_LINKER "" CACHE STRING
   "Default linker to use (linker name or absolute path, empty for platform default)")

clang/include/clang/Config/config.h.cmake

 #cmakedefine01 CLANG_ENABLE_STATIC_ANALYZER
 
 /* Spawn a new process clang.exe for the CC1 tool invocation, when necessary */
 #cmakedefine01 CLANG_SPAWN_CC1
 
 /* Whether to enable opaque pointers by default */
 #cmakedefine01 CLANG_ENABLE_OPAQUE_POINTERS_INTERNAL
 
+#cmakedefine CLANG_DEFAULT_CRASH_DIAG_LEVEL ${${CLANG_DEFAULT_CRASH_DIAG_LEVEL}}
+
 #endif

clang/lib/Driver/Driver.cpp

 // preprocessed source file(s).  Request that the developer attach the
 // diagnostic information to a bug report.
 void Driver::generateCompilationDiagnostics(
     Compilation &C, const Command &FailingCommand,
     StringRef AdditionalInformation, CompilationDiagnosticReport *Report) {
   if (C.getArgs().hasArg(options::OPT_fno_crash_diagnostics))
     return;
 
-  unsigned Level = 1;
+  unsigned Level = CLANG_DEFAULT_CRASH_DIAG_LEVEL;
   if (Arg *A = C.getArgs().getLastArg(options::OPT_fcrash_diagnostics_EQ)) {
     Level = llvm::StringSwitch<unsigned>(A->getValue())
                 .Case("off", 0)
                 .Case("compiler", 1)
                 .Case("all", 2)
-                .Default(1);
+                .Default(CLANG_DEFAULT_CRASH_DIAG_LEVEL);
   }
   if (!Level)
     return;
 
   // Don't try to generate diagnostics for dsymutil jobs.
   if (FailingCommand.getCreator().isDsymutilJob())
     return;
 

clang/test/Driver/lit.local.cfg

driver_overwrite_env_vars = ['MACOSX_DEPLOYMENT_TARGET',
                              'CC_LOG_DIAGNOSTICS', 'CC_PRINT_PROC_STAT']
 
 for name in driver_overwrite_env_vars:
   if name in config.environment:
     del config.environment[name]
 
 if llvm_config.use_lld(required=False):
     config.available_features.add('lld')
+
+if config.is_clang_crash_diag_default:
+  config.available_features.add("clang_crash_diag_default")

clang/test/Driver/lld-repro.c

 // CHECK-NEXT: note: diagnostic msg: {{.*}}lld-repro-{{.*}}.c
 // CHECK-NEXT: note: diagnostic msg: {{.*}}linker-crash-{{.*}}.tar
 // CHECK-NEXT: note: diagnostic msg: {{.*}}lld-repro-{{.*}}.sh
 // CHECK-NEXT: note: diagnostic msg:
 // CHECK: ********************
 
 // RUN: not %clang %s -nostartfiles -nostdlib -fuse-ld=lld -gen-reproducer=error -fcrash-diagnostics-dir=%t -fcrash-diagnostics=compiler 2>&1 \
 // RUN:   | FileCheck %s --check-prefix=NO-LINKER
+
+// RUN: %if clang_crash_diag_default %{ \
 // RUN: not %clang %s -nostartfiles -nostdlib -fuse-ld=lld -gen-reproducer=error -fcrash-diagnostics-dir=%t 2>&1 \
-// RUN:   | FileCheck %s --check-prefix=NO-LINKER
+// RUN:   | FileCheck %s --check-prefix=NO-LINKER \
+// RUN: %}
 
 // NO-LINKER-NOT: Preprocessed source(s) and associated run script(s) are located at:
 
 extern int a;
 int main() {
   return a;
 }

clang/test/lit.site.cfg.py.in

 config.enable_threads = @LLVM_ENABLE_THREADS@
 config.host_arch = "@HOST_ARCH@"
 config.python_executable = "@Python3_EXECUTABLE@"
 config.use_z3_solver = lit_config.params.get('USE_Z3_SOLVER', "@USE_Z3_SOLVER@")
 config.has_plugins = @CLANG_PLUGIN_SUPPORT@
 config.clang_vendor_uti = "@CLANG_VENDOR_UTI@"
 config.llvm_external_lit = path(r"@LLVM_EXTERNAL_LIT@")
 config.standalone_build = @CLANG_BUILT_STANDALONE@
+config.is_clang_crash_diag_default = @CLANG_CRASH_DIAG_IS_DEFAULT@
 
 import lit.llvm
 lit.llvm.initialize(lit_config, config)
 
 # Let the main config do the real work.
 lit_config.load_config(
     config, os.path.join(config.clang_src_dir, "test/lit.cfg.py"))

llvm/test/CMakeLists.txt

llvm_canonicalize_cmake_booleans(
   LLVM_BYE_LINK_INTO_TOOLS
   LLVM_HAVE_TF_AOT
   LLVM_HAVE_TF_API
   LLVM_INLINER_MODEL_AUTOGENERATED
   LLVM_RAEVICT_MODEL_AUTOGENERATED
   LLVM_ENABLE_EXPENSIVE_CHECKS
   LLVM_INCLUDE_DXIL_TESTS
   LLVM_TOOL_LLVM_DRIVER_BUILD
+  CLANG_CRASH_DIAG_IS_DEFAULT
   )
 
 configure_lit_site_cfg(
   ${CMAKE_CURRENT_SOURCE_DIR}/lit.site.cfg.py.in
   ${CMAKE_CURRENT_BINARY_DIR}/lit.site.cfg.py
   MAIN_CONFIG
   ${CMAKE_CURRENT_SOURCE_DIR}/lit.cfg.py
   PATHS

llvm/utils/gn/secondary/clang/include/clang/Config/BUILD.gn

values = [
     "DEFAULT_SYSROOT=",
     "GCC_INSTALL_PREFIX=",
     "BACKEND_PACKAGE_STRING=LLVM ${llvm_version}git",
     "ENABLE_LINKER_BUILD_ID=",
     "ENABLE_X86_RELAX_RELOCATIONS=1",
     "CLANG_ENABLE_OBJC_REWRITER=1",  # FIXME: flag?
     "CLANG_SYSTEMZ_DEFAULT_ARCH=z10",
     "PPC_LINUX_DEFAULT_IEEELONGDOUBLE=",
+    "CLANG_DEFAULT_CRASH_DIAG_LEVEL=1",
   ]
 
   if (clang_enable_arcmt) {
     values += [ "CLANG_ENABLE_ARCMT=1" ]
   } else {
     values += [ "CLANG_ENABLE_ARCMT=" ]
   }
 

utils/bazel/llvm-project-overlay/clang/include/clang/Config/config.h

 #define CLANG_ENABLE_STATIC_ANALYZER 1
 
 /* Spawn a new process clang.exe for the CC1 tool invocation, when necessary */
 #define CLANG_SPAWN_CC1 0
 
 /* Whether to enable opaque pointers by default */
 #define CLANG_ENABLE_OPAQUE_POINTERS_INTERNAL 1
 
+/* Default crash diagnostics level. 1 implies crash diagnostics from the
+ * compiler only
+ */
+#define CLANG_DEFAULT_CRASH_DIAG_LEVEL 1
+
 /* Directly provide definitions here behind platform preprocessor definitions.
  * The preprocessor conditions are sufficient to handle all of the configuration
  * on platforms targeted by Bazel, and defining these here more faithfully
  * matches how the users of this header expect things to work with CMake.
  */
 
 #ifndef _WIN32
 #define CLANG_HAVE_RLIMITS 1
 #endif
 
 #endif