Unable to build the AArch64 binutils sources with NDEBUG defined

Unable to build the AArch64 binutils sources with NDEBUG defined

[Nick Clifton]

Hi Andrew,

   Sorry for picking on you with an AArch64 build problem,
   but you seem to active in the sources at the moment and
   this should not be a big issue to solve:

   If you build the AArch64 binutils sources with NDEBUG defined,
   the assert() function call becomes a no-op and this in turn
   leads to some compile time warnings about unused variables.
   Since we treat compile time warnings as errors, this means
   that the build fails.  For example:

   $ .../configure --quiet --target=aarch64-linux-gnu CFLAGS="-O2 -g -DNDEBUG"
   $ make all-binutils
   [...]
   opcodes/aarch64-asm.c: In function 'aarch64_ins_sve_strided_reglist':
   opcodes/aarch64-asm.c:1328:16: error: unused variable 'mask' [-Werror=unused-variable]

   There are a couple more like this.

   Fixing them is either a case of replacing the assert() with an "if () return <fail>"
   type statement, or marking the variable as possibly unused:

diff --git a/opcodes/aarch64-asm.c b/opcodes/aarch64-asm.c
index 565c4b10559..29e96e244bb 100644
--- a/opcodes/aarch64-asm.c
+++ b/opcodes/aarch64-asm.c
@@ -1325,7 +1325,7 @@ aarch64_ins_sve_strided_reglist (const aarch64_operand *self,
                                    ATTRIBUTE_UNUSED)
  {
    unsigned int num_regs = get_operand_specific_data (self);
-  unsigned int mask = 16 | (16 / num_regs - 1);
+  unsigned int mask ATTRIBUTE_UNUSED = 16 | (16 / num_regs - 1);
    unsigned int val = info->reglist.first_regno;
    assert ((val & mask) == val);
    insert_field (self->fields[0], code, val >> 4, 0);

   If you do not have the time to look into this issue, please let me know
   and I will fix the problems myself.

Cheers
   Nick

[PATCH] aarch64: Eliminate unused variable warnings with -DNDEBUG

[Andrew Carlotti]

Ok for master and 2.42 branch?

Incidentally, while two of these sections of code were added recently, the
issue in aarch64-dis.c has been present since July 2022.


diff --git a/opcodes/aarch64-asm.c b/opcodes/aarch64-asm.c
index 565c4b10559d1800c39f118d225088da5c1c3e36..29e96e244bb2d01ec5514f5d66acc2ff0c724503 100644
--- a/opcodes/aarch64-asm.c
+++ b/opcodes/aarch64-asm.c
@@ -1325,7 +1325,7 @@ aarch64_ins_sve_strided_reglist (const aarch64_operand *self,
 				   ATTRIBUTE_UNUSED)
 {
   unsigned int num_regs = get_operand_specific_data (self);
-  unsigned int mask = 16 | (16 / num_regs - 1);
+  unsigned int mask ATTRIBUTE_UNUSED = 16 | (16 / num_regs - 1);
   unsigned int val = info->reglist.first_regno;
   assert ((val & mask) == val);
   insert_field (self->fields[0], code, val >> 4, 0);
diff --git a/opcodes/aarch64-dis.c b/opcodes/aarch64-dis.c
index f63b74706f6da606d3df848bd722e5c2ae3f3ecb..82d2f8f8251f0f48e06a85360ebfdf258247de20 100644
--- a/opcodes/aarch64-dis.c
+++ b/opcodes/aarch64-dis.c
@@ -3686,8 +3686,9 @@ get_style_text (enum disassembler_style style)
 
       for (i = 0; i <= 0xf; ++i)
 	{
-	  int res = snprintf (&formats[i][0], sizeof (formats[i]), "%c%x%c",
-			      STYLE_MARKER_CHAR, i, STYLE_MARKER_CHAR);
+	  int res ATTRIBUTE_UNUSED
+	    = snprintf (&formats[i][0], sizeof (formats[i]), "%c%x%c",
+			STYLE_MARKER_CHAR, i, STYLE_MARKER_CHAR);
 	  assert (res == 3);
 	}
 
diff --git a/opcodes/aarch64-opc.c b/opcodes/aarch64-opc.c
index 5b76f2cfa2191fc388adf55ad174f4a1829202f3..965c1c0698c5ab97abde32cd502ae342ad9e34a1 100644
--- a/opcodes/aarch64-opc.c
+++ b/opcodes/aarch64-opc.c
@@ -3335,12 +3335,11 @@ aarch64_match_operands_constraint (aarch64_inst *inst,
 	       invalid tying and invalid qualifiers, the error about
 	       qualifiers would suggest several alternative instructions
 	       that also have invalid tying.  */
-	    enum aarch64_operand_class op_class1
+	    enum aarch64_operand_class op_class
 	       = aarch64_get_operand_class (inst->operands[0].type);
-	    enum aarch64_operand_class op_class2
-	       = aarch64_get_operand_class (inst->operands[i].type);
-	    assert (op_class1 == op_class2);
-	    if (op_class1 == AARCH64_OPND_CLASS_SVE_REGLIST
+	    assert (aarch64_get_operand_class (inst->operands[i].type)
+		    == op_class);
+	    if (op_class == AARCH64_OPND_CLASS_SVE_REGLIST
 		? ((inst->operands[0].reglist.first_regno
 		    != inst->operands[i].reglist.first_regno)
 		   || (inst->operands[0].reglist.num_regs

Re: [PATCH] aarch64: Eliminate unused variable warnings with -DNDEBUG

[Nick Clifton]

Hi Andrew,

> Ok for master and 2.42 branch?

Approved - please apply to master and branch.

> Incidentally, while two of these sections of code were added recently, the
> issue in aarch64-dis.c has been present since July 2022.

Yes - I only recently decided to add a build to my build farm that was configured
with -DNDEBUG.  The idea being to catch problems exactly like this...

Cheers
   Nick