[PATCH][GCC][AArch64] Make processing less fragile in config.gcc

[Tamar Christina <Tamar dot Christina at arm dot com>]

Hi All,

Due to config.gcc all the options need to be on one line because of the grep
lines which would select only the first line of the option.

This causes it not to select the right bits on options that are spread over
multiple lines when the --with-arch configure option is used.  The issue happens
silently and you just get a compiler with an incorrect set of default flags.

The current rules are quite rigid:

   1) No space between the AARCH64_OPT_EXTENSION and the opening (.
   2) No space between the opening ( and the extension name.
   3) No space after the extension name before the ,.
   4) Spaces are only allowed after a , and around |.

This patch makes this a lot less fragile by using the C pre-processor to flatten
the list and then provides much more flexible regex using group matching to
process the options instead of string replacement.  This removes all the
restrictions above and makes the code a bit more readable.

Bootstrapped Regtested on aarch64-none-linux-gnu and no issues.

Ok for trunk? and for eventual backport?

Thanks,
Tamar

gcc/ChangeLog:

2019-05-21  Tamar Christina  <tamar.christina@arm.com>

	PR target/89517
	* config.gcc: Relax parsing of AARCH64_OPT_EXTENSION.
	* config/aarch64/aarch64-option-extensions.def: Add new comments
	and restore easier to read options.

-- 

diff --git a/gcc/config.gcc b/gcc/config.gcc
index 76bb316942d93448e6354a89a8266118ee767601..effd42e8612ff0432f7b4dc656531a9cb11f99cd 100644
--- a/gcc/config.gcc
+++ b/gcc/config.gcc
@@ -3828,32 +3828,40 @@ case "${target}" in
 				  sed -e 's/,.*$//'`
 			  fi
 
+			  # Use the pre-processor to strip flatten the options.
+			  # This makes the format less rigid than if we use
+			  # grep and sed directly here.
+			  opt_macro="AARCH64_OPT_EXTENSION(A, B, C, D, E, F)=A, B, C, D, E, F"
+			  options_parsed="`$ac_cv_prog_CPP -D"$opt_macro" -x c \
+				${srcdir}/config/aarch64/aarch64-option-extensions.def`"
+
+			  # Match one element inside AARCH64_OPT_EXTENSION, we
+			  # consume anything that's not a ,.
+			  elem="[ 	]*\([^,]\+\)[ 	]*"
+
+			  # Repeat the pattern for the number of entries in the
+			  # AARCH64_OPT_EXTENSION, currently 6 times.
+			  sed_patt="^$elem,$elem,$elem,$elem,$elem,$elem"
+
 			  while [ x"$ext_val" != x ]
 			  do
 				ext_val=`echo $ext_val | sed -e 's/\+//'`
 				ext=`echo $ext_val | sed -e 's/\+.*//'`
 				base_ext=`echo $ext | sed -e 's/^no//'`
+				opt_line=`echo -e "$options_parsed" | \
+					grep "^\"$base_ext\""`
 
 				if [ x"$base_ext" = x ] \
-				    || grep "^AARCH64_OPT_EXTENSION(\"$base_ext\"," \
-				    ${srcdir}/config/aarch64/aarch64-option-extensions.def \
-				    > /dev/null; then
-
-				  ext_canon=`grep "^AARCH64_OPT_EXTENSION(\"$base_ext\"," \
-					${srcdir}/config/aarch64/aarch64-option-extensions.def | \
-					sed -e 's/^[^,]*,[ 	]*//' | \
-					sed -e 's/,.*$//'`
-				  ext_on=`grep "^AARCH64_OPT_EXTENSION(\"$base_ext\"," \
-					${srcdir}/config/aarch64/aarch64-option-extensions.def | \
-					sed -e 's/^[^,]*,[ 	]*[^,]*,[ 	]*//' | \
-					sed -e 's/,.*$//' | \
-					sed -e 's/).*$//'`
-				  ext_off=`grep "^AARCH64_OPT_EXTENSION(\"$base_ext\"," \
-					${srcdir}/config/aarch64/aarch64-option-extensions.def | \
-					sed -e 's/^[^,]*,[ 	]*[^,]*,[ 	]*[^,]*,[ 	]*//' | \
-					sed -e 's/,.*$//' | \
-					sed -e 's/).*$//'`
-
+				    || [[ -n $opt_line ]]; then
+
+				  # These regexp extract the elements based on
+				  # their group match index in the regexp.
+				  ext_canon=`echo -e "$opt_line" | \
+					sed -e "s/$sed_patt/\2/"`
+				  ext_on=`echo -e "$opt_line" | \
+					sed -e "s/$sed_patt/\3/"`
+				  ext_off=`echo -e "$opt_line" | \
+					sed -e "s/$sed_patt/\4/"`
 
 				  if [ $ext = $base_ext ]; then
 					# Adding extension
diff --git a/gcc/config/aarch64/aarch64-option-extensions.def b/gcc/config/aarch64/aarch64-option-extensions.def
index 53dcd03590d2e4eebac83f03039c442fca7f5d5d..9b1f11c4170793aefda67beb4b56cacdf6f527fd 100644
--- a/gcc/config/aarch64/aarch64-option-extensions.def
+++ b/gcc/config/aarch64/aarch64-option-extensions.def
@@ -45,29 +45,34 @@
      entries: aes, pmull, sha1, sha2 being present).  In that case this field
      should contain a space (" ") separated list of the strings in 'Features'
      that are required.  Their order is not important.  An empty string means
-     do not detect this feature during auto detection.  */
+     do not detect this feature during auto detection.
 
-/* NOTE: This file is being parsed by config.gcc and so the
-   AARCH64_OPT_EXTENSION must adhere to a strict format:
-   1) No space between the AARCH64_OPT_EXTENSION and the opening (.
-   2) No space between the opening ( and the extension name.
-   3) No space after the extension name before the ,.
-   4) Spaces are only allowed after a , and around |.
-   5) Everything must be on one line.  */
+     NOTE: Any changes to the AARCH64_OPT_EXTENSION macro need to be mirrored in
+     config.gcc.  */
 
 /* Enabling "fp" just enables "fp".
    Disabling "fp" also disables "simd", "crypto", "fp16", "aes", "sha2",
    "sha3", sm3/sm4 and "sve".  */
-AARCH64_OPT_EXTENSION("fp", AARCH64_FL_FP, 0, AARCH64_FL_SIMD | AARCH64_FL_CRYPTO | AARCH64_FL_F16 | AARCH64_FL_AES | AARCH64_FL_SHA2 | AARCH64_FL_SHA3 | AARCH64_FL_SM4 | AARCH64_FL_SVE, false, "fp")
+AARCH64_OPT_EXTENSION("fp", AARCH64_FL_FP, 0, AARCH64_FL_SIMD | AARCH64_FL_CRYPTO |\
+		      AARCH64_FL_F16 | AARCH64_FL_AES | AARCH64_FL_SHA2 |\
+		      AARCH64_FL_SHA3 | AARCH64_FL_SM4 | AARCH64_FL_SVE, \
+		      false, "fp")
 
 /* Enabling "simd" also enables "fp".
    Disabling "simd" also disables "crypto", "dotprod", "aes", "sha2", "sha3",
    "sm3/sm4" and "sve".  */
-AARCH64_OPT_EXTENSION("simd", AARCH64_FL_SIMD, AARCH64_FL_FP, AARCH64_FL_CRYPTO | AARCH64_FL_DOTPROD | AARCH64_FL_AES | AARCH64_FL_SHA2 | AARCH64_FL_SHA3 | AARCH64_FL_SM4 | AARCH64_FL_SVE, false, "asimd")
+AARCH64_OPT_EXTENSION("simd", AARCH64_FL_SIMD, AARCH64_FL_FP, AARCH64_FL_CRYPTO |\
+		      AARCH64_FL_DOTPROD | AARCH64_FL_AES | AARCH64_FL_SHA2 |\
+		      AARCH64_FL_SHA3 | AARCH64_FL_SM4 | AARCH64_FL_SVE,
+		      false, "asimd")
 
 /* Enabling "crypto" also enables "fp", "simd", "aes" and "sha2".
    Disabling "crypto" disables "crypto", "aes", "sha2", "sha3" and "sm3/sm4".  */
-AARCH64_OPT_EXTENSION("crypto", AARCH64_FL_CRYPTO, AARCH64_FL_FP | AARCH64_FL_SIMD | AARCH64_FL_AES | AARCH64_FL_SHA2, AARCH64_FL_AES | AARCH64_FL_SHA2 |AARCH64_FL_SHA3 | AARCH64_FL_SM4, true, "aes pmull sha1 sha2")
+AARCH64_OPT_EXTENSION("crypto", AARCH64_FL_CRYPTO,
+		      AARCH64_FL_FP | AARCH64_FL_SIMD | AARCH64_FL_AES |\
+		      AARCH64_FL_SHA2,\
+		      AARCH64_FL_AES | AARCH64_FL_SHA2 |AARCH64_FL_SHA3 | AARCH64_FL_SM4,\
+		      true, "aes pmull sha1 sha2")
 
 /* Enabling or disabling "crc" only changes "crc".  */
 AARCH64_OPT_EXTENSION("crc", AARCH64_FL_CRC, 0, 0, false, "crc32")
@@ -77,18 +82,21 @@ AARCH64_OPT_EXTENSION("lse", AARCH64_FL_LSE, 0, 0, false, "atomics")
 
 /* Enabling "fp16" also enables "fp".
    Disabling "fp16" disables "fp16", "fp16fml" and "sve".  */
-AARCH64_OPT_EXTENSION("fp16", AARCH64_FL_F16, AARCH64_FL_FP, AARCH64_FL_F16FML | AARCH64_FL_SVE, false, "fphp asimdhp")
+AARCH64_OPT_EXTENSION("fp16", AARCH64_FL_F16, AARCH64_FL_FP,
+		      AARCH64_FL_F16FML | AARCH64_FL_SVE, false, "fphp asimdhp")
 
 /* Enabling or disabling "rcpc" only changes "rcpc".  */
 AARCH64_OPT_EXTENSION("rcpc", AARCH64_FL_RCPC, 0, 0, false, "lrcpc")
 
 /* Enabling "rdma" also enables "fp", "simd".
    Disabling "rdma" just disables "rdma".  */
-AARCH64_OPT_EXTENSION("rdma", AARCH64_FL_RDMA, AARCH64_FL_FP | AARCH64_FL_SIMD, 0, false, "asimdrdm")
+AARCH64_OPT_EXTENSION("rdma", AARCH64_FL_RDMA, \
+		      AARCH64_FL_FP | AARCH64_FL_SIMD, 0, false, "asimdrdm")
 
 /* Enabling "dotprod" also enables "simd".
    Disabling "dotprod" only disables "dotprod".  */
-AARCH64_OPT_EXTENSION("dotprod", AARCH64_FL_DOTPROD, AARCH64_FL_SIMD, 0, false, "asimddp")
+AARCH64_OPT_EXTENSION("dotprod", AARCH64_FL_DOTPROD, AARCH64_FL_SIMD, 0, \
+		      false, "asimddp")
 
 /* Enabling "aes" also enables "simd".
    Disabling "aes" just disables "aes".  */
@@ -96,23 +104,29 @@ AARCH64_OPT_EXTENSION("aes", AARCH64_FL_AES, AARCH64_FL_SIMD, 0, false, "aes")
 
 /* Enabling "sha2" also enables "simd".
    Disabling "sha2" just disables "sha2".  */
-AARCH64_OPT_EXTENSION("sha2", AARCH64_FL_SHA2, AARCH64_FL_SIMD, 0, false, "sha1 sha2")
+AARCH64_OPT_EXTENSION("sha2", AARCH64_FL_SHA2, AARCH64_FL_SIMD, 0, false, \
+		      "sha1 sha2")
 
 /* Enabling "sha3" enables "simd" and "sha2".
    Disabling "sha3" just disables "sha3".  */
-AARCH64_OPT_EXTENSION("sha3", AARCH64_FL_SHA3, AARCH64_FL_SIMD | AARCH64_FL_SHA2, 0, false, "sha3 sha512")
+AARCH64_OPT_EXTENSION("sha3", AARCH64_FL_SHA3, \
+		      AARCH64_FL_SIMD | AARCH64_FL_SHA2, 0, false, \
+		      "sha3 sha512")
 
 /* Enabling "sm4" also enables "simd".
    Disabling "sm4" just disables "sm4".  */
-AARCH64_OPT_EXTENSION("sm4", AARCH64_FL_SM4, AARCH64_FL_SIMD, 0, false, "sm3 sm4")
+AARCH64_OPT_EXTENSION("sm4", AARCH64_FL_SM4, AARCH64_FL_SIMD, 0, false, \
+		      "sm3 sm4")
 
 /* Enabling "fp16fml" also enables "fp" and "fp16".
    Disabling "fp16fml" just disables "fp16fml".  */
-AARCH64_OPT_EXTENSION("fp16fml", AARCH64_FL_F16FML, AARCH64_FL_FP | AARCH64_FL_F16, 0, false, "asimdfml")
+AARCH64_OPT_EXTENSION("fp16fml", AARCH64_FL_F16FML, \
+		      AARCH64_FL_FP | AARCH64_FL_F16, 0, false, "asimdfml")
 
 /* Enabling "sve" also enables "fp16", "fp" and "simd".
    Disabling "sve" just disables "sve".  */
-AARCH64_OPT_EXTENSION("sve", AARCH64_FL_SVE, AARCH64_FL_FP | AARCH64_FL_SIMD | AARCH64_FL_F16, 0, false, "sve")
+AARCH64_OPT_EXTENSION("sve", AARCH64_FL_SVE, AARCH64_FL_FP | AARCH64_FL_SIMD | \
+		      AARCH64_FL_F16, 0, false, "sve")
 
 /* Enabling/Disabling "profile" does not enable/disable any other feature.  */
 AARCH64_OPT_EXTENSION("profile", AARCH64_FL_PROFILE, 0, 0, false, "")