Enable clang-specific warnings on the clang-cl build

instead of just trying to be MSVC

This also fixes the new warnings that are caught.
These include:
  * Unreachable code after GTEST_SKIP (this is kind of ugly)
  * Some -Wundef warnings
  * A -Wshadow warning in vlog_config.cc

PiperOrigin-RevId: 838046186
Change-Id: Ief48d6db2b8755d2173997d052560880593d5819

Author: Abseil Team

absl/base/config.h

@@ -755,7 +755,7 @@ static_assert(ABSL_INTERNAL_INLINE_NAMESPACE_STR[0] != 'h' ||
 #ifdef ABSL_INTERNAL_HAS_CXA_DEMANGLE
 #error ABSL_INTERNAL_HAS_CXA_DEMANGLE cannot be directly set
 #elif defined(OS_ANDROID) && (defined(__i386__) || defined(__x86_64__))
-#undef ABSL_INTERNAL_HAS_CXA_DEMANGLE
+#define ABSL_INTERNAL_HAS_CXA_DEMANGLE 0
 #elif defined(__GNUC__)
 #define ABSL_INTERNAL_HAS_CXA_DEMANGLE 1
 #elif defined(__clang__) && !defined(_MSC_VER)

absl/container/btree_test.cc

@@ -2048,10 +2048,7 @@ TEST(Btree, ExtractAndGetNextEndIter) {
 
 TEST(Btree, ExtractDoesntCauseExtraMoves) {
 #ifdef _MSC_VER
-  // This conditional is to avoid an unreachable code warning.
-  if (_MSC_VER > 0) {
-    GTEST_SKIP() << "This test fails on MSVC.";
-  }
+  GTEST_SKIP() << "This test fails on MSVC.";
 #endif
 
   using Set = absl::btree_set<MovableOnlyInstance>;

absl/copts/GENERATED_AbseilCopts.cmake

@@ -10,46 +10,6 @@ list(APPEND ABSL_CLANG_CL_FLAGS
     "/D_CRT_SECURE_NO_WARNINGS"
     "/D_SCL_SECURE_NO_WARNINGS"
     "/D_ENABLE_EXTENDED_ALIGNED_STORAGE"
-    "-Wmost"
-    "-Wextra"
-    "-Wc++98-compat-extra-semi"
-    "-Wcast-qual"
-    "-Wconversion"
-    "-Wdeprecated-pragma"
-    "-Wfloat-overflow-conversion"
-    "-Wfloat-zero-conversion"
-    "-Wfor-loop-analysis"
-    "-Wformat-security"
-    "-Wgnu-redeclared-enum"
-    "-Winfinite-recursion"
-    "-Winvalid-constexpr"
-    "-Wliteral-conversion"
-    "-Wmissing-declarations"
-    "-Wnullability-completeness"
-    "-Woverlength-strings"
-    "-Wpointer-arith"
-    "-Wself-assign"
-    "-Wshadow-all"
-    "-Wshorten-64-to-32"
-    "-Wsign-conversion"
-    "-Wstring-conversion"
-    "-Wtautological-overlap-compare"
-    "-Wtautological-unsigned-zero-compare"
-    "-Wthread-safety"
-    "-Wundef"
-    "-Wuninitialized"
-    "-Wunreachable-code"
-    "-Wunused-comparison"
-    "-Wunused-local-typedefs"
-    "-Wunused-result"
-    "-Wvla"
-    "-Wwrite-strings"
-    "-Wno-float-conversion"
-    "-Wno-implicit-float-conversion"
-    "-Wno-implicit-int-float-conversion"
-    "-Wno-unknown-warning-option"
-    "-Wno-unused-command-line-argument"
-    "-DNOMINMAX"
 )
 
 list(APPEND ABSL_CLANG_CL_TEST_FLAGS
@@ -59,43 +19,6 @@ list(APPEND ABSL_CLANG_CL_TEST_FLAGS
     "/D_CRT_SECURE_NO_WARNINGS"
     "/D_SCL_SECURE_NO_WARNINGS"
     "/D_ENABLE_EXTENDED_ALIGNED_STORAGE"
-    "-Wmost"
-    "-Wextra"
-    "-Wc++98-compat-extra-semi"
-    "-Wcast-qual"
-    "-Wconversion"
-    "-Wdeprecated-pragma"
-    "-Wfloat-overflow-conversion"
-    "-Wfloat-zero-conversion"
-    "-Wfor-loop-analysis"
-    "-Wformat-security"
-    "-Wgnu-redeclared-enum"
-    "-Winfinite-recursion"
-    "-Winvalid-constexpr"
-    "-Wliteral-conversion"
-    "-Wmissing-declarations"
-    "-Woverlength-strings"
-    "-Wpointer-arith"
-    "-Wself-assign"
-    "-Wshadow-all"
-    "-Wstring-conversion"
-    "-Wtautological-overlap-compare"
-    "-Wtautological-unsigned-zero-compare"
-    "-Wthread-safety"
-    "-Wundef"
-    "-Wuninitialized"
-    "-Wunreachable-code"
-    "-Wunused-comparison"
-    "-Wunused-local-typedefs"
-    "-Wunused-result"
-    "-Wvla"
-    "-Wwrite-strings"
-    "-Wno-float-conversion"
-    "-Wno-implicit-float-conversion"
-    "-Wno-implicit-int-float-conversion"
-    "-Wno-unknown-warning-option"
-    "-Wno-unused-command-line-argument"
-    "-DNOMINMAX"
     "-Wno-deprecated-declarations"
     "-Wno-implicit-int-conversion"
     "-Wno-missing-prototypes"
@@ -161,7 +84,6 @@ list(APPEND ABSL_GCC_TEST_FLAGS
 
 list(APPEND ABSL_LLVM_FLAGS
     "-Wall"
-    "-Wmost"
     "-Wextra"
     "-Wc++98-compat-extra-semi"
     "-Wcast-qual"
@@ -205,7 +127,6 @@ list(APPEND ABSL_LLVM_FLAGS
 
 list(APPEND ABSL_LLVM_TEST_FLAGS
     "-Wall"
-    "-Wmost"
     "-Wextra"
     "-Wc++98-compat-extra-semi"
     "-Wcast-qual"

absl/copts/GENERATED_copts.bzl

@@ -11,46 +11,6 @@ ABSL_CLANG_CL_FLAGS = [
     "/D_CRT_SECURE_NO_WARNINGS",
     "/D_SCL_SECURE_NO_WARNINGS",
     "/D_ENABLE_EXTENDED_ALIGNED_STORAGE",
-    "-Wmost",
-    "-Wextra",
-    "-Wc++98-compat-extra-semi",
-    "-Wcast-qual",
-    "-Wconversion",
-    "-Wdeprecated-pragma",
-    "-Wfloat-overflow-conversion",
-    "-Wfloat-zero-conversion",
-    "-Wfor-loop-analysis",
-    "-Wformat-security",
-    "-Wgnu-redeclared-enum",
-    "-Winfinite-recursion",
-    "-Winvalid-constexpr",
-    "-Wliteral-conversion",
-    "-Wmissing-declarations",
-    "-Wnullability-completeness",
-    "-Woverlength-strings",
-    "-Wpointer-arith",
-    "-Wself-assign",
-    "-Wshadow-all",
-    "-Wshorten-64-to-32",
-    "-Wsign-conversion",
-    "-Wstring-conversion",
-    "-Wtautological-overlap-compare",
-    "-Wtautological-unsigned-zero-compare",
-    "-Wthread-safety",
-    "-Wundef",
-    "-Wuninitialized",
-    "-Wunreachable-code",
-    "-Wunused-comparison",
-    "-Wunused-local-typedefs",
-    "-Wunused-result",
-    "-Wvla",
-    "-Wwrite-strings",
-    "-Wno-float-conversion",
-    "-Wno-implicit-float-conversion",
-    "-Wno-implicit-int-float-conversion",
-    "-Wno-unknown-warning-option",
-    "-Wno-unused-command-line-argument",
-    "-DNOMINMAX",
 ]
 
 ABSL_CLANG_CL_TEST_FLAGS = [
@@ -60,43 +20,6 @@ ABSL_CLANG_CL_TEST_FLAGS = [
     "/D_CRT_SECURE_NO_WARNINGS",
     "/D_SCL_SECURE_NO_WARNINGS",
     "/D_ENABLE_EXTENDED_ALIGNED_STORAGE",
-    "-Wmost",
-    "-Wextra",
-    "-Wc++98-compat-extra-semi",
-    "-Wcast-qual",
-    "-Wconversion",
-    "-Wdeprecated-pragma",
-    "-Wfloat-overflow-conversion",
-    "-Wfloat-zero-conversion",
-    "-Wfor-loop-analysis",
-    "-Wformat-security",
-    "-Wgnu-redeclared-enum",
-    "-Winfinite-recursion",
-    "-Winvalid-constexpr",
-    "-Wliteral-conversion",
-    "-Wmissing-declarations",
-    "-Woverlength-strings",
-    "-Wpointer-arith",
-    "-Wself-assign",
-    "-Wshadow-all",
-    "-Wstring-conversion",
-    "-Wtautological-overlap-compare",
-    "-Wtautological-unsigned-zero-compare",
-    "-Wthread-safety",
-    "-Wundef",
-    "-Wuninitialized",
-    "-Wunreachable-code",
-    "-Wunused-comparison",
-    "-Wunused-local-typedefs",
-    "-Wunused-result",
-    "-Wvla",
-    "-Wwrite-strings",
-    "-Wno-float-conversion",
-    "-Wno-implicit-float-conversion",
-    "-Wno-implicit-int-float-conversion",
-    "-Wno-unknown-warning-option",
-    "-Wno-unused-command-line-argument",
-    "-DNOMINMAX",
     "-Wno-deprecated-declarations",
     "-Wno-implicit-int-conversion",
     "-Wno-missing-prototypes",
@@ -162,7 +85,6 @@ ABSL_GCC_TEST_FLAGS = [
 
 ABSL_LLVM_FLAGS = [
     "-Wall",
-    "-Wmost",
     "-Wextra",
     "-Wc++98-compat-extra-semi",
     "-Wcast-qual",
@@ -206,7 +128,6 @@ ABSL_LLVM_FLAGS = [
 
 ABSL_LLVM_TEST_FLAGS = [
     "-Wall",
-    "-Wmost",
     "-Wextra",
     "-Wc++98-compat-extra-semi",
     "-Wcast-qual",

absl/copts/copts.py

@@ -41,13 +41,8 @@
     "-Wno-unused-private-field",
 ]
 
-# https://github.com/llvm/llvm-project/issues/102982
-# A list of LLVM base flags without -Wall. This is because clang-cl
-# translates -Wall to -Weverything on Windows, mimicking MSVCs
-# behavior. On most other platforms, -Wall is just a set of very good
-# default flags.
-ABSL_LLVM_BASE_FLAGS = [
-    "-Wmost",
+ABSL_LLVM_FLAGS = [
+    "-Wall",
     "-Wextra",
     "-Wc++98-compat-extra-semi",
     "-Wcast-qual",
@@ -94,8 +89,6 @@
     "-DNOMINMAX",
 ]
 
-ABSL_LLVM_FLAGS = ["-Wall"] + ABSL_LLVM_BASE_FLAGS
-
 ABSL_LLVM_TEST_ADDITIONAL_FLAGS = [
     "-Wno-deprecated-declarations",
     "-Wno-implicit-int-conversion",
@@ -171,15 +164,9 @@ def GccStyleFilterAndCombine(default_flags, test_flags):
     "ABSL_LLVM_TEST_FLAGS": GccStyleFilterAndCombine(
         ABSL_LLVM_FLAGS, ABSL_LLVM_TEST_ADDITIONAL_FLAGS
     ),
-    "ABSL_CLANG_CL_FLAGS": (
-        MSVC_BIG_WARNING_FLAGS + MSVC_DEFINES + ABSL_LLVM_BASE_FLAGS
-    ),
+    "ABSL_CLANG_CL_FLAGS": MSVC_BIG_WARNING_FLAGS + MSVC_DEFINES,
     "ABSL_CLANG_CL_TEST_FLAGS": (
-        MSVC_BIG_WARNING_FLAGS
-        + MSVC_DEFINES
-        + GccStyleFilterAndCombine(
-            ABSL_LLVM_BASE_FLAGS, ABSL_LLVM_TEST_ADDITIONAL_FLAGS
-        )
+        MSVC_BIG_WARNING_FLAGS + MSVC_DEFINES + ABSL_LLVM_TEST_ADDITIONAL_FLAGS
     ),
     "ABSL_MSVC_FLAGS": (
         MSVC_BIG_WARNING_FLAGS + MSVC_WARNING_FLAGS + MSVC_DEFINES

absl/debugging/internal/demangle.cc

@@ -28,7 +28,7 @@
 #include "absl/base/config.h"
 #include "absl/debugging/internal/demangle_rust.h"
 
-#ifdef ABSL_INTERNAL_HAS_CXA_DEMANGLE
+#if ABSL_INTERNAL_HAS_CXA_DEMANGLE
 #include <cxxabi.h>
 #endif
 
@@ -2941,7 +2941,7 @@ std::string DemangleString(const char* mangled) {
   std::string out;
   int status = 0;
   char* demangled = nullptr;
-#ifdef ABSL_INTERNAL_HAS_CXA_DEMANGLE
+#if ABSL_INTERNAL_HAS_CXA_DEMANGLE
   demangled = abi::__cxa_demangle(mangled, nullptr, nullptr, &status);
 #endif
   if (status == 0 && demangled != nullptr) {

absl/debugging/stacktrace_test.cc

@@ -94,23 +94,15 @@ TEST(StackTrace, HugeFrame) {
 // This is a separate function to avoid inlining.
 ABSL_ATTRIBUTE_NOINLINE static void FixupNoFixupEquivalenceNoInline() {
 #if !ABSL_HAVE_ATTRIBUTE_WEAK
-  const char* kSkipReason = "Need weak symbol support";
-#elif defined(__riscv)
-  const char* kSkipReason =
-      "Skipping test on RISC-V due to pre-existing failure";
-#elif defined(_WIN32)
+  GTEST_SKIP() << "Need weak symbol support";
+#endif
+#if defined(__riscv)
+  GTEST_SKIP() << "Skipping test on RISC-V due to pre-existing failure";
+#endif
+#if defined(_WIN32)
   // TODO(b/434184677): Add support for fixups on Windows if needed
-  const char* kSkipReason =
-      "Skipping test on Windows due to lack of support for fixups";
-#else
-  const char* kSkipReason = nullptr;
+  GTEST_SKIP() << "Skipping test on Windows due to lack of support for fixups";
 #endif
-
-  // This conditional is to avoid an unreachable code warning.
-  if (kSkipReason != nullptr) {
-    GTEST_SKIP() << kSkipReason;
-  }
-
   bool can_rely_on_frame_pointers = false;
   if (!can_rely_on_frame_pointers) {
     GTEST_SKIP() << "Frame pointers are required, but not guaranteed in OSS";
@@ -241,20 +233,13 @@ TEST(StackTrace, FixupNoFixupEquivalence) { FixupNoFixupEquivalenceNoInline(); }
 
 TEST(StackTrace, FixupLowStackUsage) {
 #if !ABSL_HAVE_ATTRIBUTE_WEAK
-  const char* kSkipReason = "Skipping test on MSVC due to weak symbols";
-#elif defined(_WIN32)
+  GTEST_SKIP() << "Skipping test on MSVC due to weak symbols";
+#endif
+#if defined(_WIN32)
   // TODO(b/434184677): Add support for fixups on Windows if needed
-  const char* kSkipReason =
-      "Skipping test on Windows due to lack of support for fixups";
-#else
-  const char* kSkipReason = nullptr;
+  GTEST_SKIP() << "Skipping test on Windows due to lack of support for fixups";
 #endif
 
-  // This conditional is to avoid an unreachable code warning.
-  if (kSkipReason != nullptr) {
-    GTEST_SKIP() << kSkipReason;
-  }
-
   const Cleanup restore_state([enable_fixup = g_enable_fixup,
                                fixup_calls = g_fixup_calls,
                                should_fixup_calls = g_should_fixup_calls]() {
@@ -291,20 +276,13 @@ TEST(StackTrace, FixupLowStackUsage) {
 
 TEST(StackTrace, CustomUnwinderPerformsFixup) {
 #if !ABSL_HAVE_ATTRIBUTE_WEAK
-  const char* kSkipReason = "Need weak symbol support";
-#elif defined(_WIN32)
+  GTEST_SKIP() << "Need weak symbol support";
+#endif
+#if defined(_WIN32)
   // TODO(b/434184677): Add support for fixups on Windows if needed
-  const char* kSkipReason =
-      "Skipping test on Windows due to lack of support for fixups";
-#else
-  const char* kSkipReason = nullptr;
+  GTEST_SKIP() << "Skipping test on Windows due to lack of support for fixups";
 #endif
 
-  // This conditional is to avoid an unreachable code warning.
-  if (kSkipReason != nullptr) {
-    GTEST_SKIP() << kSkipReason;
-  }
-
   constexpr int kSkip = 1;  // Skip our own frame, whose return PCs won't match
   constexpr auto kStackCount = 1;
 

absl/hash/internal/low_level_hash_test.cc

@@ -361,13 +361,9 @@ TEST(LowLevelHashTest, VerifyGolden) {
 #if defined(ABSL_IS_BIG_ENDIAN) || !defined(ABSL_HAVE_INTRINSIC_INT128) || \
     UINTPTR_MAX != UINT64_MAX
   constexpr uint64_t kGolden[kNumGoldenOutputs] = {};
-  // This conditional is to avoid an unreachable code warning.
-  bool skip = true;
-  if (skip) {
-    GTEST_SKIP()
-        << "We only maintain golden data for little endian 64 bit systems with "
-           "128 bit intristics.";
-  }
+  GTEST_SKIP()
+      << "We only maintain golden data for little endian 64 bit systems with "
+         "128 bit intristics.";
 #elif defined(__SSE4_2__) && defined(__AES__)
   constexpr uint64_t kGolden[kNumGoldenOutputs] = {
       0xd6bdb2c9ba5e55f2, 0xffd3e23d4115a8ae, 0x2c3218ef486127de,