Re: GOLD: RFA: Fixing a coverty error for aarch64.cc

[Pedro Alves <palves at redhat dot com>]

I would suggest letting the compiler handle computing
array sizes.  Something like the below.  (Build tested
only, feel free to run with it).   If you restore the
pointer with something like:

 +  const static Insntype* ST_E_835769_INSNS = ST_E_843419_INSNS;
 +
 [...]
 -  // ST_E_835769 has the same stub template as ST_E_843419.
 -  install_insn_template_insns(ST_E_835769, ST_E_843419);
 +  install_insn_template(ST_E_835769);
 
Then the compiler catches the problem:

 src/gold/aarch64.cc:798:65: error: no matching function for call to ‘{anonymous}::Stub_template<false>::Stub_template(const Insntype*&)’
    const static Stub_template<big_endian> template_##T (I##_INSNS); \
                                                                 ^
 src/gold/aarch64.cc:802:3: note: in expansion of macro ‘install_insn_template_insns’
    install_insn_template_insns(T, T)
    ^
 src/gold/aarch64.cc:808:3: note: in expansion of macro ‘install_insn_template’
     install_insn_template(ST_E_835769);
     ^
 src/gold/aarch64.cc:711:3: note: candidate: template<long unsigned int insn_num_>{anonymous}::Stub_template<big_endian>::Stub_template(const typename {anonymous}::AArch64_insn_utilities<big_endian>::Insntype(&)[insn_num_])
    Stub_template
    ^
 src/gold/aarch64.cc:711:3: note:   template argument deduction/substitution failed:
 src/gold/aarch64.cc:798:65: note:   mismatched types ‘const Insntype [insn_num_]’ and ‘const Insntype* {aka const unsigned int*}’
    const static Stub_template<big_endian> template_##T (I##_INSNS); \
 

(ST_NONE_INSNS is removed because (const-expression) arrays of 0
length are not valid C++, and compilers reject them / SFINAE them
out when deciding which constructor to call.)

>From c7cd91832535b3989ec8f41a3d1eb51c7acc0ee4 Mon Sep 17 00:00:00 2001
From: Pedro Alves <palves@redhat.com>
Date: Fri, 20 Jan 2017 10:52:05 +0000
Subject: [PATCH]

---
 gold/aarch64.cc | 27 +++++++++++++++++----------
 1 file changed, 17 insertions(+), 10 deletions(-)

diff --git a/gold/aarch64.cc b/gold/aarch64.cc
index facbbd8..ab80472 100644
--- a/gold/aarch64.cc
+++ b/gold/aarch64.cc
@@ -703,6 +703,16 @@ enum
 template<bool big_endian>
 struct Stub_template
 {
+  Stub_template ()
+    : insns(NULL), insn_num(0)
+  { }
+
+  template<size_t insn_num_>
+  Stub_template
+    (const typename AArch64_insn_utilities<big_endian>::Insntype (&insns_)[insn_num_])
+      : insns(insns_), insn_num(insn_num_)
+  { }
+
   const typename AArch64_insn_utilities<big_endian>::Insntype* insns;
   const int insn_num;
 };
@@ -746,8 +756,6 @@ template<bool big_endian>
 Stub_template_repertoire<big_endian>::Stub_template_repertoire()
 {
   // Insn array definitions.
-  const static Insntype ST_NONE_INSNS[] = {};
-
   const static Insntype ST_ADRP_BRANCH_INSNS[] =
     {
       0x90000010,	/*	adrp	ip0, X		   */
@@ -784,20 +792,19 @@ Stub_template_repertoire<big_endian>::Stub_template_repertoire()
       0x14000000,    /* b <label> */
     };
 
-  // ST_E_835769 has the same stub template as ST_E_843419.
-  const static Insntype* ST_E_835769_INSNS = ST_E_843419_INSNS;
-
-#define install_insn_template(T) \
-  const static Stub_template<big_endian> template_##T = {  \
-    T##_INSNS, sizeof(T##_INSNS) / sizeof(T##_INSNS[0]) }; \
+#define install_insn_template_insns(T, I)				\
+  const static Stub_template<big_endian> template_##T (I##_INSNS);	\
   this->stub_templates_[T] = &template_##T
 
-  install_insn_template(ST_NONE);
+#define install_insn_template(T)					\
+  install_insn_template_insns(T, T)
+
   install_insn_template(ST_ADRP_BRANCH);
   install_insn_template(ST_LONG_BRANCH_ABS);
   install_insn_template(ST_LONG_BRANCH_PCREL);
   install_insn_template(ST_E_843419);
-  install_insn_template(ST_E_835769);
+  // ST_E_835769 has the same stub template as ST_E_843419.
+  install_insn_template_insns(ST_E_835769, ST_E_843419);
 
 #undef install_insn_template
 }
-- 
2.5.5