An update, to consider the new warning options added in gcc 14,15
and clang 17 to 20.
2025-05-09 Bruno Haible <br...@clisp.org>
HACKING: Update.
* HACKING: Update for gcc 15 and clang 20.
diff --git a/HACKING b/HACKING
index e0f54a4ccf..eb1cd20031 100644
--- a/HACKING
+++ b/HACKING
@@ -182,11 +182,11 @@ there are three possible approaches:
You should generally fix all compiler warnings that you see from this
approach.
-* If you are developing on a glibc system and have GCC version 13 binaries
+* If you are developing on a glibc system and have GCC version 15 binaries
available, here's a recipe that will find more mistakes, but is nearly
as easy to use. Here, different warning options are needed for C and
for C++:
- $ WARN_GCC13=`echo '
+ $ WARN_GCC15=`echo '
-fanalyzer
-Wall
-Warith-conversion
@@ -194,10 +194,12 @@ there are three possible approaches:
-Wdate-time
-Wduplicated-cond
-Wextra
+ -Wflex-array-member-not-at-end
-Wformat-signedness
-Winit-self
-Winvalid-pch
-Wlogical-op
+ -Wmaybe-musttail-local-addr
-Wmissing-include-dirs
-Wopenmp-simd
-Woverlength-strings
@@ -256,18 +258,18 @@ there are three possible approaches:
-Wno-type-limits
-Wno-unused-parameter
' | tr -d '\n' | sed -e 's/ */ /g'`
- $ WARN_CFLAGS_GCC13="$WARN_GCC13 -Wnested-externs -Wshadow=local
-Wno-discarded-qualifiers"
- $ WARN_CXXFLAGS_GCC13="$WARN_GCC13 -Wno-cpp"
- $ ./configure CFLAGS="-O2 -g $WARN_CFLAGS_GCC13" CXXFLAGS="-O2 -g
$WARN_CXXFLAGS_GCC13"
+ $ WARN_CFLAGS_GCC15="$WARN_GCC15 -Wmissing-variable-declarations
-Wnested-externs -Wshadow=local -Wno-discarded-qualifiers"
+ $ WARN_CXXFLAGS_GCC15="$WARN_GCC15 -Wno-cpp"
+ $ ./configure CFLAGS="-O2 -g $WARN_CFLAGS_GCC15" CXXFLAGS="-O2 -g
$WARN_CXXFLAGS_GCC15"
$ make
You should generally fix all compiler warnings that you see from this
approach, or report when this approach produced a pointless warning
- (so that we can fix the value of WARN_GCC13 above).
+ (so that we can fix the value of WARN_GCC15 above).
-* If you are developing on a glibc system and have GCC version 13 binaries
+* If you are developing on a glibc system and have GCC version 15 binaries
available: Here's a recipe that will find even more mistakes, but it
requires that you are willing to filter out and ignore pointless warnings.
- $ WARN_GCC13=`echo '
+ $ WARN_GCC15=`echo '
-fanalyzer
-Wall
-Warith-conversion
@@ -275,10 +277,12 @@ there are three possible approaches:
-Wdate-time
-Wduplicated-cond
-Wextra
+ -Wflex-array-member-not-at-end
-Wformat-signedness
-Winit-self
-Winvalid-pch
-Wlogical-op
+ -Wmaybe-musttail-local-addr
-Wmissing-include-dirs
-Wnull-dereference
-Wopenmp-simd
@@ -323,9 +327,9 @@ there are three possible approaches:
-Wno-type-limits
-Wno-unused-parameter
' | tr -d '\n' | sed -e 's/ */ /g'`
- $ WARN_CFLAGS_GCC13="$WARN_GCC13 -Wnested-externs -Wshadow=local"
- $ WARN_CXXFLAGS_GCC13="$WARN_GCC13 -Wno-cpp"
- $ ./configure CFLAGS="-O2 -g $WARN_CFLAGS_GCC13" CXXFLAGS="-O2 -g
$WARN_CXXFLAGS_GCC13"
+ $ WARN_CFLAGS_GCC15="$WARN_GCC15 -Wmissing-variable-declarations
-Wnested-externs -Wshadow=local"
+ $ WARN_CXXFLAGS_GCC15="$WARN_GCC15 -Wno-cpp"
+ $ ./configure CFLAGS="-O2 -g $WARN_CFLAGS_GCC15" CXXFLAGS="-O2 -g
$WARN_CXXFLAGS_GCC15"
$ make
With this approach, use your own judgement whether to fix warnings
arising from your new code or not.
@@ -335,24 +339,28 @@ there are three possible approaches:
these warnings, we prefer to report them in the GCC bug tracker
and wait until they are fixed in a future GCC release.
-Similarly, for clang version 16 you can use the following recipe, that uses
+Similarly, for clang version 20 you can use the following recipe, that uses
selected warning options from
-https://releases.llvm.org/16.0.0/tools/clang/docs/DiagnosticsReference.html :
- $ WARN_CLANG16=`echo '
+https://releases.llvm.org/20.1.0/tools/clang/docs/DiagnosticsReference.html :
+ $ WARN_CLANG20=`echo '
-Wall
-Wanon-enum-enum-conversion
-Warc-repeated-use-of-weak
-Warray-bounds-pointer-arithmetic
-Warray-parameter
-Watomic-properties
+ -Wauto-decl-extensions
-Wbinary-literal
-Wbit-int-extension
-Wbitfield-enum-conversion
-Wbitwise-op-parentheses
-Wbool-operation
-Wc++-compat
+ -Wc23-compat
+ -Wc23-extensions
-Wc2x-compat
-Wc2x-extensions
+ -Wc23-extensions
-Wc99-compat
-Wc99-designator
-Wc99-extensions
@@ -398,7 +406,6 @@
https://releases.llvm.org/16.0.0/tools/clang/docs/DiagnosticsReference.html :
-Wexplicit-ownership-type
-Wextra
-Wextra-semi
- -Wfixed-enum-extension
-Wflexible-array-extensions
-Wfloat-overflow-conversion
-Wfloat-zero-conversion
@@ -506,7 +513,10 @@
https://releases.llvm.org/16.0.0/tools/clang/docs/DiagnosticsReference.html :
-Wpragma-pack
-Wpragma-pack-suspicious-include
-Wpragmas
+ -Wpre-c11-compat
+ -Wpre-c23-compat
-Wpre-c2x-compat
+ -Wpre-c2y-compat
-Wpre-openmp-51-compat
-Wprofile-instr-missing
-Wquoted-include-in-framework-header
@@ -518,6 +528,7 @@
https://releases.llvm.org/16.0.0/tools/clang/docs/DiagnosticsReference.html :
-Wredundant-parens
-Wreorder
-Wreorder-ctor
+ -Wreserved-attribute-identifier
-Wreserved-user-defined-literal
-Wretained-language-linkage
-Wselector
@@ -534,6 +545,7 @@
https://releases.llvm.org/16.0.0/tools/clang/docs/DiagnosticsReference.html :
-Wshift-sign-overflow
-Wsigned-enum-bitfield
-Wsometimes-uninitialized
+ -Wsource-uses-openacc
-Wsource-uses-openmp
-Wspir-compat
-Wstatic-in-inline
@@ -547,6 +559,7 @@
https://releases.llvm.org/16.0.0/tools/clang/docs/DiagnosticsReference.html :
-Wtautological-bitwise-compare
-Wtautological-compare
-Wtautological-constant-in-range-compare
+ -Wtautological-negation-compare
-Wtautological-overlap-compare
-Wtautological-type-limit-compare
-Wtautological-unsigned-char-zero-compare
@@ -594,6 +607,7 @@
https://releases.llvm.org/16.0.0/tools/clang/docs/DiagnosticsReference.html :
-Wunused-variable
-Wvariadic-macros
-Wvector-conversion
+ -Wvla-cxx-extension
-Wweak-template-vtables
-Wweak-vtables
-Wzero-length-array
@@ -623,7 +637,7 @@
https://releases.llvm.org/16.0.0/tools/clang/docs/DiagnosticsReference.html :
-Wno-unused-command-line-argument
-Wno-user-defined-warnings
' | tr -d '\n' | sed -e 's/ */ /g'`
- $ ./configure CFLAGS="-O2 -g $WARN_CLANG16" CXXFLAGS="-O2 -g $WARN_CLANG16"
+ $ ./configure CFLAGS="-O2 -g $WARN_CLANG20" CXXFLAGS="-O2 -g $WARN_CLANG20"
$ make
Again, use your own judgement to determine whether to fix or ignore a
specific warning.
