Cheng Shao pushed to branch wip/rts-rm-c99-check at Glasgow Haskell Compiler / GHC
Commits:
3c9bcb37 by Cheng Shao at 2025-09-29T20:07:47+02:00
autoconf/ghc-toolchain: remove obsolete C99 check
This patch removes obsolete c99 check from autoconf/ghc-toolchain. For
all toolchain & platform combination we support, gnu11 or above is
already supported without any -std flag required, and our RTS already
required C11 quite a few years ago, so the C99 check is completely
pointless.
- - - - -
6 changed files:
- configure.ac
- distrib/configure.ac.in
- m4/fp_cmm_cpp_cmd_with_args.m4
- − m4/fp_set_cflags_c99.m4
- utils/ghc-toolchain/src/GHC/Toolchain/Tools/Cc.hs
- utils/ghc-toolchain/src/GHC/Toolchain/Tools/Cpp.hs
Changes:
=====================================
configure.ac
=====================================
@@ -448,11 +448,6 @@ AC_SUBST([CmmCPPCmd])
AC_SUBST([CmmCPPArgs])
AC_SUBST([CmmCPPSupportsG0])
-FP_SET_CFLAGS_C99([CC],[CFLAGS],[CPPFLAGS])
-FP_SET_CFLAGS_C99([CC_STAGE0],[CONF_CC_OPTS_STAGE0],[CONF_CPP_OPTS_STAGE0])
-FP_SET_CFLAGS_C99([CC],[CONF_CC_OPTS_STAGE1],[CONF_CPP_OPTS_STAGE1])
-FP_SET_CFLAGS_C99([CC],[CONF_CC_OPTS_STAGE2],[CONF_CPP_OPTS_STAGE2])
-
dnl ** Do we have a compatible emsdk version?
dnl --------------------------------------------------------------
EMSDK_VERSION("3.1.20", "", "")
=====================================
distrib/configure.ac.in
=====================================
@@ -163,11 +163,6 @@ AC_SUBST([CmmCPPCmd])
AC_SUBST([CmmCPPArgs])
AC_SUBST([CmmCPPSupportsG0])
-FP_SET_CFLAGS_C99([CC],[CFLAGS],[CPPFLAGS])
-dnl FP_SET_CFLAGS_C99([CC_STAGE0],[CONF_CC_OPTS_STAGE0],[CONF_CPP_OPTS_STAGE0])
-FP_SET_CFLAGS_C99([CC],[CONF_CC_OPTS_STAGE1],[CONF_CPP_OPTS_STAGE1])
-FP_SET_CFLAGS_C99([CC],[CONF_CC_OPTS_STAGE2],[CONF_CPP_OPTS_STAGE2])
-
dnl ** Which ld to use?
dnl --------------------------------------------------------------
FIND_LD([$target],[GccUseLdOpt])
=====================================
m4/fp_cmm_cpp_cmd_with_args.m4
=====================================
@@ -56,27 +56,6 @@ else
AC_MSG_RESULT([no])
fi
-AC_MSG_CHECKING([the C-- preprocessor for C99 support])
-cat > conftest.c <
-#if !defined __STDC_VERSION__ || __STDC_VERSION__ < 199901L
-# error "Compiler does not advertise C99 conformance"
-#endif
-EOF
-if "$CMM_CPP_CMD" $CMM_CPP_ARGS conftest.c -o conftest -g0 >/dev/null 2>&1; then
- AC_MSG_RESULT([yes])
-else
- # Try -std=gnu99
- if "$CMM_CPP_CMD" -std=gnu99 $CMM_CPP_ARGS conftest.c -o conftest -g0 >/dev/null 2>&1; then
- $3="-std=gnu99 $$3"
- AC_MSG_RESULT([needs -std=gnu99])
- else
- AC_MSG_ERROR([C99-compatible compiler needed])
- fi
-fi
-rm -f conftest.c conftest.o conftest
-
-
$2="$CMM_CPP_CMD"
$3="$$3 $CMM_CPP_ARGS"
@@ -85,4 +64,3 @@ unset CMM_CPP_CMD
unset CMM_CPP_ARGS
])
-
=====================================
m4/fp_set_cflags_c99.m4 deleted
=====================================
@@ -1,38 +0,0 @@
-# FP_SET_CFLAGS_C99
-# ----------------------------------
-# figure out which CFLAGS are needed to place the compiler into C99 mode
-# $1 is name of CC variable (unmodified)
-# $2 is name of CC flags variable (augmented if needed)
-# $3 is name of CPP flags variable (augmented if needed)
-AC_DEFUN([FP_SET_CFLAGS_C99],
-[
- dnl save current state of AC_PROG_CC_C99
- FP_COPY_SHELLVAR([CC],[fp_save_CC])
- FP_COPY_SHELLVAR([CFLAGS],[fp_save_CFLAGS])
- FP_COPY_SHELLVAR([CPPFLAGS],[fp_save_CPPFLAGS])
- FP_COPY_SHELLVAR([ac_cv_prog_cc_c99],[fp_save_cc_c99])
- dnl set local state
- CC="$$1"
- CFLAGS="$$2"
- CPPFLAGS="$$3"
- unset ac_cv_prog_cc_c99
- dnl perform detection
- AC_PROG_CC_C99
- fp_cc_c99="$ac_cv_prog_cc_c99"
- case "x$ac_cv_prog_cc_c99" in
- x) ;; # noop
- xno) AC_MSG_ERROR([C99-compatible compiler needed]) ;;
- *) $2="$$2 $ac_cv_prog_cc_c99"
- $3="$$3 $ac_cv_prog_cc_c99"
- ;;
- esac
- dnl restore saved state
- FP_COPY_SHELLVAR([fp_save_CC],[CC])
- FP_COPY_SHELLVAR([fp_save_CFLAGS],[CFLAGS])
- FP_COPY_SHELLVAR([fp_save_CPPFLAGS],[CPPFLAGS])
- FP_COPY_SHELLVAR([fp_save_cc_c99],[ac_cv_prog_cc_c99])
- dnl cleanup
- unset fp_save_CC
- unset fp_save_CFLAGS
- unset fp_save_cc_c99
-])
=====================================
utils/ghc-toolchain/src/GHC/Toolchain/Tools/Cc.hs
=====================================
@@ -11,7 +11,6 @@ module GHC.Toolchain.Tools.Cc
, compileC
, compileAsm
, addPlatformDepCcFlags
- , checkC99Support
) where
import Control.Monad
@@ -51,12 +50,8 @@ findCc archOs llvmTarget progOpt = do
cc1 <- ignoreUnusedArgs cc0
cc2 <- ccSupportsTarget archOs llvmTarget cc1
checking "whether Cc works" $ checkCcWorks cc2
- cc3 <- oneOf "cc doesn't support C99" $ map checkC99Support
- [ cc2
- , cc2 & _ccFlags %++ "-std=gnu99"
- ]
- checkCcSupportsExtraViaCFlags cc3
- return cc3
+ checkCcSupportsExtraViaCFlags cc2
+ return cc2
checkCcWorks :: Cc -> M ()
checkCcWorks cc = withTempDir $ \dir -> do
@@ -88,17 +83,6 @@ ccSupportsTarget archOs target cc =
checking "whether Cc supports --target" $
supportsTarget archOs _ccProgram checkCcWorks target cc
-checkC99Support :: Cc -> M Cc
-checkC99Support cc = checking "for C99 support" $ withTempDir $ \dir -> do
- let test_o = dir "test.o"
- compileC cc test_o $ unlines
- [ "#include "
- , "#if !defined __STDC_VERSION__ || __STDC_VERSION__ < 199901L"
- , "# error \"Compiler does not advertise C99 conformance\""
- , "#endif"
- ]
- return cc
-
checkCcSupportsExtraViaCFlags :: Cc -> M ()
checkCcSupportsExtraViaCFlags cc = checking "whether cc supports extra via-c flags" $ withTempDir $ \dir -> do
let test_o = dir "test.o"
=====================================
utils/ghc-toolchain/src/GHC/Toolchain/Tools/Cpp.hs
=====================================
@@ -19,7 +19,7 @@ import GHC.Toolchain.Prelude
import GHC.Toolchain.Program
import GHC.Toolchain.Tools.Cc
-import GHC.Toolchain.Utils (withTempDir, oneOf, expectFileExists)
+import GHC.Toolchain.Utils (withTempDir, expectFileExists)
newtype Cpp = Cpp { cppProgram :: Program
}
@@ -160,13 +160,7 @@ findJsCpp progOpt cc = checking "for JavaScript C preprocessor" $ do
findCmmCpp :: ProgOpt -> Cc -> M CmmCpp
findCmmCpp progOpt cc = checking "for a Cmm preprocessor" $ do
-- Use the specified CPP or try to use the c compiler
- foundCppProg <- findProgram "Cmm preprocessor" progOpt [] <|> pure (programFromOpt progOpt (prgPath $ ccProgram cc) [])
- -- Check whether the C preprocessor needs -std=gnu99 (only very old toolchains need this)
- Cc cpp <- oneOf "cc doesn't support C99" $ map checkC99Support
- [ Cc foundCppProg
- , Cc (foundCppProg & _prgFlags %++ "-std=gnu99")
- ]
-
+ cpp <- findProgram "Cmm preprocessor" progOpt [] <|> pure (programFromOpt progOpt (prgPath $ ccProgram cc) [])
cmmCppSupportsG0 <- withTempDir $ \dir -> do
let conftest = dir "conftest.c"
writeFile conftest "int main(void) {}"
@@ -181,14 +175,9 @@ findCmmCpp progOpt cc = checking "for a Cmm preprocessor" $ do
findCpp :: ProgOpt -> Cc -> M Cpp
findCpp progOpt cc = checking "for C preprocessor" $ do
-- Use the specified CPP or try to use the c compiler
- foundCppProg <- findProgram "C preprocessor" progOpt [] <|> pure (programFromOpt progOpt (prgPath $ ccProgram cc) [])
- -- Check whether the C preprocessor needs -std=gnu99 (only very old toolchains need this)
- Cc cpp2 <- oneOf "cc doesn't support C99" $ map checkC99Support
- [ Cc foundCppProg
- , Cc (foundCppProg & _prgFlags %++ "-std=gnu99")
- ]
+ cpp <- findProgram "C preprocessor" progOpt [] <|> pure (programFromOpt progOpt (prgPath $ ccProgram cc) [])
-- Always add the -E flag to the CPP, regardless of the user options
- let cppProgram = addFlagIfNew "-E" cpp2
+ let cppProgram = addFlagIfNew "-E" cpp
return Cpp{cppProgram}
--------------------------------------------------------------------------------
View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/3c9bcb378efe476fed312fe4e12c6a51...
--
View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/3c9bcb378efe476fed312fe4e12c6a51...
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