Add the ability to turn on warnings that get disabled in tests

in GCC and LLVM build configs

This was accomplished by adding GccStyleFilterAndCombine() in copts.py

Previously, if we had a default warning of the form -Wwarning, adding
-Wno-warning to the list of test warnings would just add conflicting
flags. We now filter -Wwarning if -Wno-warning is added to the test warnings.

PiperOrigin-RevId: 495683815
Change-Id: I5dfd8a30b0be09d6b48237f61d598230ab9027db

1 files changed, 122 insertions, 96 deletions

diff --git a/absl/copts/copts.py b/absl/copts/copts.py
index 732af9ea..b7f68c7d 100644
--- a/absl/copts/copts.py
+++ b/absl/copts/copts.py
@@ -11,12 +11,76 @@ The generated copts are consumed by configure_copts.bzl and
 AbseilConfigureCopts.cmake.
 """
 
-# /Wall with msvc includes unhelpful warnings such as C4711, C4710, ...
-MSVC_BIG_WARNING_FLAGS = [
-    "/W3",
+ABSL_GCC_FLAGS = [
+    "-Wall",
+    "-Wextra",
+    "-Wcast-qual",
+    "-Wconversion-null",
+    "-Wformat-security",
+    "-Wmissing-declarations",
+    "-Woverlength-strings",
+    "-Wpointer-arith",
+    "-Wundef",
+    "-Wunused-local-typedefs",
+    "-Wunused-result",
+    "-Wvarargs",
+    "-Wvla",  # variable-length array
+    "-Wwrite-strings",
+    # Don't define min and max macros (Build on Windows using gcc)
+    "-DNOMINMAX",
+]
+
+ABSL_GCC_TEST_ADDITIONAL_FLAGS = [
+    "-Wno-deprecated-declarations",
+    "-Wno-missing-declarations",
+    "-Wno-sign-compare",
+    "-Wno-unused-function",
+    "-Wno-unused-parameter",
+    "-Wno-unused-private-field",
 ]
 
-LLVM_TEST_DISABLE_WARNINGS_FLAGS = [
+ABSL_LLVM_FLAGS = [
+    "-Wall",
+    "-Wextra",
+    "-Wcast-qual",
+    "-Wconversion",
+    "-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",
+    "-Wundef",
+    "-Wuninitialized",
+    "-Wunreachable-code",
+    "-Wunused-comparison",
+    "-Wunused-local-typedefs",
+    "-Wunused-result",
+    "-Wvla",
+    "-Wwrite-strings",
+    # Warnings that are enabled by group warning flags like -Wall that we
+    # explicitly disable.
+    "-Wno-float-conversion",
+    "-Wno-implicit-float-conversion",
+    "-Wno-implicit-int-float-conversion",
+    # Disable warnings on unknown warning flags (when warning flags are
+    # unknown on older compiler versions)
+    "-Wno-unknown-warning-option",
+    # Don't define min and max macros (Build on Windows using clang)
+    "-DNOMINMAX",
+]
+
+ABSL_LLVM_TEST_ADDITIONAL_FLAGS = [
     "-Wno-deprecated-declarations",
     "-Wno-implicit-int-conversion",
     "-Wno-missing-prototypes",
@@ -36,6 +100,28 @@ LLVM_TEST_DISABLE_WARNINGS_FLAGS = [
     "-Wno-gnu-zero-variadic-macro-arguments",
 ]
 
+# /Wall with msvc includes unhelpful warnings such as C4711, C4710, ...
+MSVC_BIG_WARNING_FLAGS = [
+    "/W3",
+]
+
+MSVC_WARNING_FLAGS = [
+    # Increase the number of sections available in object files
+    "/bigobj",
+    "/wd4005",  # macro-redefinition
+    "/wd4068",  # unknown pragma
+    # qualifier applied to function type has no meaning; ignored
+    "/wd4180",
+    # conversion from 'type1' to 'type2', possible loss of data
+    "/wd4244",
+    # conversion from 'size_t' to 'type', possible loss of data
+    "/wd4267",
+    # The decorated name was longer than the compiler limit
+    "/wd4503",
+    # forcing value to bool 'true' or 'false' (performance warning)
+    "/wd4800",
+]
+
 MSVC_DEFINES = [
     "/DNOMINMAX",  # Don't define min and max macros (windows.h)
     # Don't bloat namespace with incompatible winsock versions.
@@ -47,103 +133,43 @@ MSVC_DEFINES = [
     "/D_ENABLE_EXTENDED_ALIGNED_STORAGE",
 ]
 
+
+def GccStyleFilterAndCombine(default_flags, test_flags):
+  """Merges default_flags and test_flags for GCC and LLVM.
+
+  Args:
+    default_flags: A list of default compiler flags
+    test_flags: A list of flags that are only used in tests
+
+  Returns:
+    A combined list of default_flags and test_flags, but with all flags of the
+    form '-Wwarning' removed if test_flags contains a flag of the form
+    '-Wno-warning'
+  """
+  remove = set(["-W" + f[5:] for f in test_flags if f[:5] == "-Wno-"])
+  return [f for f in default_flags if f not in remove] + test_flags
+
 COPT_VARS = {
-    "ABSL_GCC_FLAGS": [
-        "-Wall",
-        "-Wextra",
-        "-Wcast-qual",
-        "-Wconversion-null",
-        "-Wformat-security",
-        "-Wmissing-declarations",
-        "-Woverlength-strings",
-        "-Wpointer-arith",
-        "-Wundef",
-        "-Wunused-local-typedefs",
-        "-Wunused-result",
-        "-Wvarargs",
-        "-Wvla",  # variable-length array
-        "-Wwrite-strings",
-        # Don't define min and max macros (Build on Windows using gcc)
-        "-DNOMINMAX",
-    ],
-    "ABSL_GCC_TEST_FLAGS": [
-        "-Wno-deprecated-declarations",
-        "-Wno-missing-declarations",
-        "-Wno-sign-compare",
-        "-Wno-unused-function",
-        "-Wno-unused-parameter",
-        "-Wno-unused-private-field",
-    ],
-    "ABSL_LLVM_FLAGS": [
-        "-Wall",
-        "-Wextra",
-        "-Wcast-qual",
-        "-Wconversion",
-        "-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",
-        "-Wundef",
-        "-Wuninitialized",
-        "-Wunreachable-code",
-        "-Wunused-comparison",
-        "-Wunused-local-typedefs",
-        "-Wunused-result",
-        "-Wvla",
-        "-Wwrite-strings",
-        # Warnings that are enabled by group warning flags like -Wall that we
-        # explicitly disable.
-        "-Wno-float-conversion",
-        "-Wno-implicit-float-conversion",
-        "-Wno-implicit-int-float-conversion",
-        # Disable warnings on unknown warning flags (when warning flags are
-        # unknown on older compiler versions)
-        "-Wno-unknown-warning-option",
-        # Don't define min and max macros (Build on Windows using clang)
-        "-DNOMINMAX",
-    ],
-    "ABSL_LLVM_TEST_FLAGS":
-        LLVM_TEST_DISABLE_WARNINGS_FLAGS,
+    "ABSL_GCC_FLAGS": ABSL_GCC_FLAGS,
+    "ABSL_GCC_TEST_FLAGS": GccStyleFilterAndCombine(
+        ABSL_GCC_FLAGS, ABSL_GCC_TEST_ADDITIONAL_FLAGS),
+    "ABSL_LLVM_FLAGS": ABSL_LLVM_FLAGS,
+    "ABSL_LLVM_TEST_FLAGS": GccStyleFilterAndCombine(
+        ABSL_LLVM_FLAGS, ABSL_LLVM_TEST_ADDITIONAL_FLAGS),
     "ABSL_CLANG_CL_FLAGS":
-        (MSVC_BIG_WARNING_FLAGS + MSVC_DEFINES),
+        MSVC_BIG_WARNING_FLAGS + MSVC_DEFINES,
     "ABSL_CLANG_CL_TEST_FLAGS":
-        LLVM_TEST_DISABLE_WARNINGS_FLAGS,
+        MSVC_BIG_WARNING_FLAGS + MSVC_DEFINES + ABSL_LLVM_TEST_ADDITIONAL_FLAGS,
     "ABSL_MSVC_FLAGS":
-        MSVC_BIG_WARNING_FLAGS + MSVC_DEFINES + [
-            # Increase the number of sections available in object files
-            "/bigobj",
-            "/wd4005",  # macro-redefinition
-            "/wd4068",  # unknown pragma
-            # qualifier applied to function type has no meaning; ignored
-            "/wd4180",
-            # conversion from 'type1' to 'type2', possible loss of data
-            "/wd4244",
-            # conversion from 'size_t' to 'type', possible loss of data
-            "/wd4267",
-            # The decorated name was longer than the compiler limit
-            "/wd4503",
-            # forcing value to bool 'true' or 'false' (performance warning)
-            "/wd4800",
+        MSVC_BIG_WARNING_FLAGS + MSVC_WARNING_FLAGS + MSVC_DEFINES,
+    "ABSL_MSVC_TEST_FLAGS":
+        MSVC_BIG_WARNING_FLAGS + MSVC_WARNING_FLAGS + MSVC_DEFINES + [
+            "/wd4018",  # signed/unsigned mismatch
+            "/wd4101",  # unreferenced local variable
+            "/wd4503",  # decorated name length exceeded, name was truncated
+            "/wd4996",  # use of deprecated symbol
+            "/DNOMINMAX",  # disable the min() and max() macros from <windows.h>
         ],
-    "ABSL_MSVC_TEST_FLAGS": [
-        "/wd4018",  # signed/unsigned mismatch
-        "/wd4101",  # unreferenced local variable
-        "/wd4503",  # decorated name length exceeded, name was truncated
-        "/wd4996",  # use of deprecated symbol
-        "/DNOMINMAX",  # disable the min() and max() macros from <windows.h>
-    ],
     "ABSL_MSVC_LINKOPTS": [
         # Object file doesn't export any previously undefined symbols
         "-ignore:4221",