pythongh-108562: Fix compiler warnings for libmpdec (python#114751)

If awailable, enable -fstrict-overflow for libmpdec. Also shut off false positive warnings (-Warray-bounds). The later was backported from mpdecimal-4.0.0.
woodruffw-forks · Mar 4, 2024 · b44c631 · b44c631
1 parent eb161c5
commit b44c631
Show file tree

Hide file tree

Showing 5 changed files with 16 additions and 3 deletions.
diff --git a/Makefile.pre.in b/Makefile.pre.in
@@ -1213,7 +1213,7 @@ PYTHON_HEADERS= \
 
 ##########################################################################
 # Build static libmpdec.a
-LIBMPDEC_CFLAGS=@LIBMPDEC_CFLAGS@ $(PY_STDMODULE_CFLAGS) $(CCSHARED)
+LIBMPDEC_CFLAGS=$(PY_STDMODULE_CFLAGS) @LIBMPDEC_CFLAGS@ $(CCSHARED)
 
 # "%.o: %c" is not portable
 Modules/_decimal/libmpdec/basearith.o: $(srcdir)/Modules/_decimal/libmpdec/basearith.c $(LIBMPDEC_HEADERS) $(PYTHON_HEADERS)

diff --git a/Misc/sbom.spdx.json b/Misc/sbom.spdx.json
diff --git a/Modules/_decimal/libmpdec/io.c b/Modules/_decimal/libmpdec/io.c
@@ -48,6 +48,7 @@
 #if defined(__GNUC__) && !defined(__INTEL_COMPILER) && __GNUC__ >= 7
   #pragma GCC diagnostic ignored "-Wimplicit-fallthrough"
   #pragma GCC diagnostic ignored "-Wmisleading-indentation"
+  #pragma GCC diagnostic ignored "-Warray-bounds"
 #endif
 
 

diff --git a/configure b/configure
diff --git a/configure.ac b/configure.ac
@@ -3896,6 +3896,11 @@ AS_VAR_IF([with_system_libmpdec], [yes], [
   LIBMPDEC_LDFLAGS="-lm \$(LIBMPDEC_A)"
   LIBMPDEC_INTERNAL="\$(LIBMPDEC_HEADERS) \$(LIBMPDEC_A)"
 
+  dnl Enable strict-overflow for libmpdec, if available, see GH-108562
+  AS_VAR_IF([ac_cv_cc_supports_fstrict_overflow], [yes], [
+    AS_VAR_APPEND([LIBMPDEC_CFLAGS], [" -fstrict-overflow"])
+  ])
+
   dnl Disable forced inlining in debug builds, see GH-94847
   AS_VAR_IF([with_pydebug], [yes], [
     AS_VAR_APPEND([LIBMPDEC_CFLAGS], [" -DTEST_COVERAGE"])