[Valgrind-developers] [valgrind] Add -fno-diagnostics-show-caret and -ftrack-macro-expansion=0.

[Florian K. <fk...@so...>]

https://sourceware.org/cgit/valgrind/commit/?id=b7d265e54132a0526473656df604af8045d35595

commit b7d265e54132a0526473656df604af8045d35595
Author: Florian Krohm <fl...@ei...>
Date:   Fri Mar 13 16:01:28 2026 +0000

    Add -fno-diagnostics-show-caret and -ftrack-macro-expansion=0.
    
    Makes GCC diagnostic messages more readable.

Diff:
---
 Makefile.all.am |  2 ++
 configure.ac    | 42 ++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 44 insertions(+)

diff --git a/Makefile.all.am b/Makefile.all.am
index 154585dce3..4f185d79cc 100644
--- a/Makefile.all.am
+++ b/Makefile.all.am
@@ -120,6 +120,8 @@ AM_CFLAGS_BASE = \
 	@FLAG_W_OLD_STYLE_DECLARATION@ \
 	@FLAG_FINLINE_FUNCTIONS@ \
 	@FLAG_FNO_STACK_PROTECTOR@ \
+	@FLAG_FNO_DIAGNOSTICS_SHOW_CARET@ \
+	@FLAG_FTRACK_MACRO_EXPANSION@ \
 	@FLAG_FSANITIZE@ \
 	-fno-strict-aliasing \
 	-fno-builtin
diff --git a/configure.ac b/configure.ac
index 8ed66042c7..ca395be823 100644
--- a/configure.ac
+++ b/configure.ac
@@ -2962,6 +2962,48 @@ CFLAGS=$safe_CFLAGS
 
 AC_SUBST(FLAG_FINLINE_FUNCTIONS)
 
+# does this compiler support -fno-diagnostics-show-caret ?
+AC_MSG_CHECKING([if gcc accepts -fno-diagnostics-show-caret])
+
+safe_CFLAGS=$CFLAGS
+CFLAGS="-fno-diagnostics-show-caret -Werror"
+
+AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[]], [[
+  return 0;
+]])], [
+no_diagnostics_show_caret=yes
+FLAG_FNO_DIAGNOSTICS_SHOW_CARET="-fno-diagnostics-show-caret"
+AC_MSG_RESULT([yes])
+], [
+no_diagnostics_show_caret=no
+FLAG_FNO_DIAGNOSTICS_SHOW_CARET=""
+AC_MSG_RESULT([no])
+])
+CFLAGS=$safe_CFLAGS
+
+AC_SUBST(FLAG_FNO_DIAGNOSTICS_SHOW_CARET)
+
+# does this compiler support -ftrack-macro-expansion=0 ?
+AC_MSG_CHECKING([if gcc accepts -ftrack-macro-expansion=0])
+
+safe_CFLAGS=$CFLAGS
+CFLAGS="-ftrack-macro-expansion=0 -Werror"
+
+AC_COMPILE_IFELSE([AC_LANG_PROGRAM([[]], [[
+  return 0;
+]])], [
+track_macro_expansion=yes
+FLAG_FTRACK_MACRO_EXPANSION="-ftrack-macro-expansion=0"
+AC_MSG_RESULT([yes])
+], [
+track_macro_expansion=no
+FLAG_FTRACK_MACRO_EXPANSION=""
+AC_MSG_RESULT([no])
+])
+CFLAGS=$safe_CFLAGS
+
+AC_SUBST(FLAG_FTRACK_MACRO_EXPANSION)
+
 # Does GCC support disabling Identical Code Folding?
 # We want to disabled Identical Code Folding for the
 # tools preload shared objects to get better backraces.