[patch][arm] (respin) Improve error checking in parsecpu.awk

[Vidya Praveen <vidyapraveen at arm dot com>]

Hello,

This patch by Richard Earnshaw was reverted along with the commit that preceded
it as the preceding commit was causing  cross-native builds  to fail and I
presumed this patch was related too.  Now I am respinning as the issue that
caused the cross-native failure have been fixed. This patch however is simply
rebased and has no other changes.

For reference, the ChangeLog of the preceding patch that broke cross-native build.

    [arm] auto-generate arm-isa.h from CPU descriptions

    This patch autogenerates arm-isa.h from new entries in arm-cpus.in.
    This has the primary advantage that it makes the description file more
    self-contained, but it also solves the 'array dimensioning' problem
    that Tamar recently encountered.  It adds two new constructs to
    arm-cpus.in: features and fgroups.  Fgroups are simply a way of naming
    a group of feature bits so that they can be referenced together.  We
    follow the convention that feature bits are all lower case, while
    fgroups are (predominantly) upper case.  This is helpful as in some
    contexts they share the same namespace.  Most of the minor changes in
    this patch are related to adopting this new naming convention.

        * config.gcc (arm*-*-*): Don't add arm-isa.h to tm_p_file.
        * config/arm/arm-isa.h: Delete.  Move definitions to ...
        * arm-cpus.in: ... here.  Use new feature and fgroup values.
        * config/arm/arm.c (arm_option_override): Use lower case for feature
        bit names.
        * config/arm/arm.h (TARGET_HARD_FLOAT): Likewise.
        (TARGET_VFP3, TARGET_VFP5, TARGET_FMA): Likewise.
        * config/arm/parsecpu.awk (END): Add new command 'isa'.
        (isa_pfx): Delete.
        (print_isa_bits_for): New function.
        (gen_isa): New function.
        (gen_comm_data): Use print_isa_bits_for.
        (define feature): New keyword.
        (define fgroup): New keyword.
        * config/arm/t-arm (OPTIONS_H_EXTRA): Add arm-isa.h
        (arm-isa.h): Add rule to generate file.
        * common/config/arm/arm-common.c: (arm_canon_arch_option): Use lower
        case for feature bit names.

Tested by building cross/cross-native arm-none-linux-gnueabihf and baremetal
cross build (arm-none-eabi) on x86_64.

OK for trunk?

Regards
VP.

gcc/ChangeLog:

[arm] Improve error checking in parsecpu.awk

This patch adds a bit more error checking to parsecpu.awk to ensure
that statements are not missing arguments or have excess arguments
beyond those permitted.  It also slightly improves the handling of
errors so that we terminate properly if parsing fails and be as
helpful as we can while in the parsing phase.

2017-09-22  Richard Earnshaw  <richard.earnshaw@arm.com>

	* config/arm/parsecpu.awk (fatal): Note that we've encountered an
	error.  Only quit immediately if parsing is complete.
	(BEGIN): Initialize fatal_err and parse_done.
	(begin fpu, end fpu): Check number of arguments.
	(begin arch, end arch): Likewise.
	(begin cpu, end cpu): Likewise.
	(cname, tune for, tune flags, architecture, fpu, option): Likewise.
	(optalias): Likewise.

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 5b9217c..4885746 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -2154,6 +2154,17 @@
 
 2017-09-06  Richard Earnshaw  <rearnsha@arm.com>
 
+	* config/arm/parsecpu.awk (fatal): Note that we've encountered an
+	error.  Only quit immediately if parsing is complete.
+	(BEGIN): Initialize fatal_err and parse_done.
+	(begin fpu, end fpu): Check number of arguments.
+	(begin arch, end arch): Likewise.
+	(begin cpu, end cpu): Likewise.
+	(cname, tune for, tune flags, architecture, fpu, option): Likewise.
+	(optalias): Likewise.
+
+2017-09-06  Richard Earnshaw  <rearnsha@arm.com>
+
 	* config.gcc (arm*-*-*): Don't add arm-isa.h to tm_p_file.
 	* config/arm/arm-isa.h: Delete.  Move definitions to ...
 	* arm-cpus.in: ... here.  Use new feature and fgroup values.
diff --git a/gcc/config/arm/parsecpu.awk b/gcc/config/arm/parsecpu.awk
index d07d3fc..0b4fc68 100644
--- a/gcc/config/arm/parsecpu.awk
+++ b/gcc/config/arm/parsecpu.awk
@@ -32,7 +32,8 @@
 
 function fatal (m) {
     print "error ("lineno"): " m > "/dev/stderr"
-    exit 1
+    fatal_err = 1
+    if (parse_done) exit 1
 }
 
 function toplevel () {
@@ -502,14 +503,18 @@ BEGIN {
     arch_name = ""
     fpu_name = ""
     lineno = 0
+    fatal_err = 0
+    parse_done = 0
     if (cmd == "") fatal("Usage parsecpu.awk -v cmd=<xyz>")
 }
 
+# New line.  Reset parse status and increment line count for error messages
 // {
     lineno++
     parse_ok = 0
 }
 
+# Comments must be on a line on their own.
 /^#/ {
     parse_ok = 1
 }
@@ -552,12 +557,14 @@ BEGIN {
 }
 
 /^begin fpu / {
+    if (NF != 3) fatal("syntax: begin fpu <name>")
     toplevel()
     fpu_name = $3
     parse_ok = 1
 }
 
 /^end fpu / {
+    if (NF != 3) fatal("syntax: end fpu <name>")
     if (fpu_name != $3) fatal("mimatched end fpu")
     if (! (fpu_name in fpu_isa)) {
 	fatal("fpu definition \"" fpu_name "\" lacks an \"isa\" statement")
@@ -570,24 +577,28 @@ BEGIN {
 }
 
 /^begin arch / {
+    if (NF != 3) fatal("syntax: begin arch <name>")
     toplevel()
     arch_name = $3
     parse_ok = 1
 }
 
 /^[ 	]*base / {
+    if (NF != 2) fatal("syntax: base <architecture-base-name>")
     if (arch_name == "") fatal("\"base\" statement outside of arch block")
     arch_base[arch_name] = $2
     parse_ok = 1
 }
 
 /^[ 	]*profile / {
+    if (NF != 2) fatal("syntax: profile <profile-name>")
     if (arch_name == "") fatal("\"profile\" statement outside of arch block")
     arch_prof[arch_name] = $2
     parse_ok = 1
 }
 
 /^end arch / {
+    if (NF != 3) fatal("syntax: end arch <name>")
     if (arch_name != $3) fatal("mimatched end arch")
     if (! arch_name in arch_tune_for) {
 	fatal("arch definition lacks a \"tune for\" statement")
@@ -603,18 +614,21 @@ BEGIN {
 }
 
 /^begin cpu / {
+    if (NF != 3) fatal("syntax: begin cpu <name>")
     toplevel()
     cpu_name = $3
     parse_ok = 1
 }
 
 /^[ 	]*cname / {
+    if (NF != 2) fatal("syntax: cname <identifier>")
     if (cpu_name == "") fatal("\"cname\" outside of cpu block")
     cpu_cnames[cpu_name] = $2
     parse_ok = 1
 }
 
 /^[ 	]*tune for / {
+    if (NF != 3) fatal("syntax: tune for <cpu-name>")
     if (cpu_name != "") {
 	cpu_tune_for[cpu_name] = $3
     } else if (arch_name != "") {
@@ -624,6 +638,7 @@ BEGIN {
 }
 
 /^[ 	]*tune flags / {
+    if (NF < 3) fatal("syntax: tune flags <flag> [<flag>]*")
     flags=""
     flag_count = NF
     for (n = 3; n <= flag_count; n++) {
@@ -640,18 +655,21 @@ BEGIN {
 }
 
 /^[ 	]*architecture / {
+    if (NF != 2) fatal("syntax: architecture <arch-name>")
     if (cpu_name == "") fatal("\"architecture\" outside of cpu block")
     cpu_arch[cpu_name] = $2
     parse_ok = 1
 }
 
 /^[ 	]*fpu / {
+    if (NF != 2) fatal("syntax: fpu <fpu-name>")
     if (cpu_name == "") fatal("\"fpu\" outside of cpu block")
     cpu_fpu[cpu_name] = $2
     parse_ok = 1
 }
 
 /^[ 	]*isa / {
+    if (NF < 2) fatal("syntax: isa <feature-or-fgroup> [<feature-or-fgroup>]*")
     flags=""
     flag_count = NF
     for (n = 2; n <= flag_count; n++) {
@@ -670,6 +688,7 @@ BEGIN {
 }
 
 /^[ 	]*option / {
+    if (NF < 4) fatal("syntax: option <name> add|remove <feature-or-fgroup>+")
     name=$2
     if ($3 == "add") {
 	remove = "false"
@@ -696,6 +715,7 @@ BEGIN {
 }
 
 /^[ 	]*optalias / {
+    if (NF != 3) fatal("syntax: optalias <name> <option-name>")
     name=$2
     alias=$3
     if (cpu_name != "") {
@@ -709,12 +729,14 @@ BEGIN {
 }
 
 /^[ 	]*costs / {
+    if (NF != 2) fatal("syntax: costs <identifier>")
     if (cpu_name == "") fatal("\"costs\" outside of cpu block")
     cpu_cost[cpu_name] = $2
     parse_ok = 1
 }
 
 /^end cpu / {
+    if (NF != 3) fatal("syntax: end cpu <name>")
     if (cpu_name != $3) fatal("mimatched end cpu")
     if (! (cpu_name in cpu_cnames)) {
 	cpu_cnames[cpu_name] = cpu_name
@@ -731,6 +753,8 @@ BEGIN {
 }
 
 END {
+    parse_done = 1
+    if (fatal_err) exit 1
     toplevel()
     if (cmd == "data") {
 	gen_data()