varasm.c (output_constant): Add new parameter merge_strings.

2018-10-04  Bernd Edlinger  <bernd.edlinger@hotmail.de>

        * varasm.c (output_constant): Add new parameter merge_strings.
        Make strings properly zero terminated in merge string sections.
        (mergeable_string_section): Don't fail if the last char is non-zero.
        (assemble_variable_contents): Handle merge string sections.
        (assemble_variable): Likewise.
        (assemble_constant_contents): Likewise.
        (output_constant_def_contents): Likewise.
        (output_constructor_array_range,
        output_constructor_regular_field): Adjust call to output_constant.
        (output_object_block): Adjust call to assemble_constant_contents
        and assemble_variable_contents.

testsuie:
2018-10-04  Bernd Edlinger  <bernd.edlinger@hotmail.de>

        * gnat.dg/string_merge1.adb: New test.
        * gnat.dg/string_merge2.adb: New test.
        * gcc.dg/merge-all-constants-1.c: Adjust test.
        * gcc.dg/merge-all-constants-2.c: New test.

From-SVN: r264850

gcc/ChangeLog

+2018-10-04  Bernd Edlinger  <bernd.edlinger@hotmail.de>
+
+	* varasm.c (output_constant): Add new parameter merge_strings.
+	Make strings properly zero terminated in merge string sections.
+	(mergeable_string_section): Don't fail if the last char is non-zero.
+	(assemble_variable_contents): Handle merge string sections.
+	(assemble_variable): Likewise.
+	(assemble_constant_contents): Likewise.
+	(output_constant_def_contents): Likewise.
+	(output_constructor_array_range,
+	output_constructor_regular_field): Adjust call to output_constant.
+	(output_object_block): Adjust call to assemble_constant_contents
+	and assemble_variable_contents.
+
 2018-10-04  Martin Liska  <mliska@suse.cz>
 
 	PR c/87483

gcc/testsuite/ChangeLog

+2018-10-04  Bernd Edlinger  <bernd.edlinger@hotmail.de>
+
+	* gnat.dg/string_merge1.adb: New test.
+	* gnat.dg/string_merge2.adb: New test.
+	* gcc.dg/merge-all-constants-1.c: Adjust test.
+	* gcc.dg/merge-all-constants-2.c: New test.
+
 2018-10-04  Bill Seurer  <seurer@linux.vnet.ibm.com>
 
 	PR target/87486

gcc/testsuite/gcc.dg/merge-all-constants-1.c

 /* { dg-do compile } */
 /* { dg-options "-w -O2 -fmerge-all-constants" } */
 
-const char str1[36] = "0123456789abcdefghijklmnopqrstuvwxyz";
+const char str1[36] = "\000123456789abcdefghijklmnopqrstuvwxyz";
 const char str2[38] = "0123456789abcdefghijklmnopqrstuvwxyz";
-const char str3[10] = "0123456789abcdefghijklmnopqrstuvwxyz";
+const char str3[10] = "\000123456789abcdefghijklmnopqrstuvwxyz";
 
-/* { dg-final { scan-assembler-not "\.rodata\.str" } } */
+/* { dg-final { scan-assembler-not "\\.rodata\\.str" } } */

gcc/testsuite/gcc.dg/merge-all-constants-2.c

+/* { dg-do compile } */
+/* { dg-options "-w -O2 -fmerge-all-constants" } */
+
+const char str1[36] = "0123456789abcdefghijklmnopqrstuvwxyz";
+const char str2[37] = "0123456789abcdefghijklmnopqrstuvwxyz";
+const char str3[10] = "0123456789abcdefghijklmnopqrstuvwxyz";
+
+/* { dg-final { scan-assembler-not "\\.rodata\[\n\r\]" } } */

gcc/testsuite/gnat.dg/string_merge1.adb

+-- { dg-do compile }
+-- { dg-options "-O1 -fmerge-all-constants" }
+
+procedure String_Merge1 is
+   procedure Process (X : String);
+   pragma Import (Ada, Process);
+begin
+   Process ("ABCD");
+end;
+
+-- We expect something like:
+
+-- .section  .rodata.str1.1,"aMS",@progbits,1
+-- .LC1:
+--     .string "ABCD"
+
+-- { dg-final { scan-assembler-times "\\.rodata\\.str" 1 } }
+-- { dg-final { scan-assembler-times "\\.string" 1 } }
+-- { dg-final { scan-assembler-times "\"ABCD\"" 1 } }

gcc/testsuite/gnat.dg/string_merge2.adb

+-- { dg-do compile }
+-- { dg-options "-O1 -fmerge-all-constants" }
+
+procedure String_Merge2 is
+   procedure Process (X : String);
+   pragma Import (Ada, Process);
+begin
+   Process ("ABCD" & Ascii.NUL);
+end;
+
+-- We expect something like:
+
+-- .section  .rodata.str1.1,"aMS",@progbits,1
+-- .LC1:
+--     .string "ABCD"
+
+-- { dg-final { scan-assembler-times "\\.rodata\\.str" 1 } }
+-- { dg-final { scan-assembler-times "\\.string" 1 } }
+-- { dg-final { scan-assembler-times "\"ABCD\"" 1 } }

gcc/varasm.c

@@ -111,7 +111,7 @@ static int compare_constant (const tree, const tree);
 static void output_constant_def_contents (rtx);
 static void output_addressed_constants (tree);
 static unsigned HOST_WIDE_INT output_constant (tree, unsigned HOST_WIDE_INT,
-					       unsigned int, bool);
+					       unsigned int, bool, bool);
 static void globalize_decl (tree);
 static bool decl_readonly_section_1 (enum section_category);
 #ifdef BSS_SECTION_ASM_OP
@@ -804,8 +804,8 @@ mergeable_string_section (tree decl ATTRIBUTE_UNUSED,
       && TREE_CODE (decl) == STRING_CST
       && TREE_CODE (TREE_TYPE (decl)) == ARRAY_TYPE
       && align <= 256
-      && (len = int_size_in_bytes (TREE_TYPE (decl))) > 0
-      && TREE_STRING_LENGTH (decl) >= len)
+      && (len = int_size_in_bytes (TREE_TYPE (decl))) >= 0
+      && TREE_STRING_LENGTH (decl) == len)
     {
       scalar_int_mode mode;
       unsigned int modesize;
@@ -835,7 +835,7 @@ mergeable_string_section (tree decl ATTRIBUTE_UNUSED,
 	      if (j == unit)
 		break;
 	    }
-	  if (i == len - unit)
+	  if (i == len - unit || (unit == 1 && i == len))
 	    {
 	      sprintf (name, "%s.str%d.%d", prefix,
 		       modesize / 8, (int) (align / 8));
@@ -2117,7 +2117,7 @@ assemble_noswitch_variable (tree decl, const char *name, section *sect,
 
 static void
 assemble_variable_contents (tree decl, const char *name,
-			    bool dont_output_data)
+			    bool dont_output_data, bool merge_strings)
 {
   /* Do any machine/system dependent processing of the object.  */
 #ifdef ASM_DECLARE_OBJECT_NAME
@@ -2140,7 +2140,7 @@ assemble_variable_contents (tree decl, const char *name,
 	output_constant (DECL_INITIAL (decl),
 			 tree_to_uhwi (DECL_SIZE_UNIT (decl)),
 			 get_variable_align (decl),
-			 false);
+			 false, merge_strings);
       else
 	/* Leave space for it.  */
 	assemble_zeros (tree_to_uhwi (DECL_SIZE_UNIT (decl)));
@@ -2316,7 +2316,9 @@ assemble_variable (tree decl, int top_level ATTRIBUTE_UNUSED,
 	switch_to_section (sect);
       if (align > BITS_PER_UNIT)
 	ASM_OUTPUT_ALIGN (asm_out_file, floor_log2 (align / BITS_PER_UNIT));
-      assemble_variable_contents (decl, name, dont_output_data);
+      assemble_variable_contents (decl, name, dont_output_data,
+				  (sect->common.flags & SECTION_MERGE)
+				  && (sect->common.flags & SECTION_STRINGS));
       if (asan_protected)
 	{
 	  unsigned HOST_WIDE_INT int size
@@ -3471,7 +3473,8 @@ maybe_output_constant_def_contents (struct constant_descriptor_tree *desc,
    constant's alignment in bits.  */
 
 static void
-assemble_constant_contents (tree exp, const char *label, unsigned int align)
+assemble_constant_contents (tree exp, const char *label, unsigned int align,
+			    bool merge_strings)
 {
   HOST_WIDE_INT size;
 
@@ -3481,7 +3484,7 @@ assemble_constant_contents (tree exp, const char *label, unsigned int align)
   targetm.asm_out.declare_constant_name (asm_out_file, label, exp, size);
 
   /* Output the value of EXP.  */
-  output_constant (exp, size, align, false);
+  output_constant (exp, size, align, false, merge_strings);
 
   targetm.asm_out.decl_end ();
 }
@@ -3522,10 +3525,13 @@ output_constant_def_contents (rtx symbol)
 		   || (VAR_P (decl) && DECL_IN_CONSTANT_POOL (decl))
 		   ? DECL_ALIGN (decl)
 		   : symtab_node::get (decl)->definition_alignment ());
-      switch_to_section (get_constant_section (exp, align));
+      section *sect = get_constant_section (exp, align);
+      switch_to_section (sect);
       if (align > BITS_PER_UNIT)
 	ASM_OUTPUT_ALIGN (asm_out_file, floor_log2 (align / BITS_PER_UNIT));
-      assemble_constant_contents (exp, XSTR (symbol, 0), align);
+      assemble_constant_contents (exp, XSTR (symbol, 0), align,
+				  (sect->common.flags & SECTION_MERGE)
+				  && (sect->common.flags & SECTION_STRINGS));
       if (asan_protected)
 	{
 	  HOST_WIDE_INT size = get_constant_size (exp);
@@ -4838,7 +4844,7 @@ output_constructor (tree, unsigned HOST_WIDE_INT, unsigned int, bool,
 
 static unsigned HOST_WIDE_INT
 output_constant (tree exp, unsigned HOST_WIDE_INT size, unsigned int align,
-		 bool reverse)
+		 bool reverse, bool merge_strings)
 {
   enum tree_code code;
   unsigned HOST_WIDE_INT thissize;
@@ -4953,10 +4959,11 @@ output_constant (tree exp, unsigned HOST_WIDE_INT size, unsigned int align,
       break;
 
     case COMPLEX_TYPE:
-      output_constant (TREE_REALPART (exp), thissize / 2, align, reverse);
+      output_constant (TREE_REALPART (exp), thissize / 2, align,
+		       reverse, false);
       output_constant (TREE_IMAGPART (exp), thissize / 2,
 		       min_align (align, BITS_PER_UNIT * (thissize / 2)),
-		       reverse);
+		       reverse, false);
       break;
 
     case ARRAY_TYPE:
@@ -4966,8 +4973,11 @@ output_constant (tree exp, unsigned HOST_WIDE_INT size, unsigned int align,
 	case CONSTRUCTOR:
 	  return output_constructor (exp, size, align, reverse, NULL);
 	case STRING_CST:
-	  thissize
-	    = MIN ((unsigned HOST_WIDE_INT)TREE_STRING_LENGTH (exp), size);
+	  thissize = (unsigned HOST_WIDE_INT)TREE_STRING_LENGTH (exp);
+	  if (merge_strings
+	      && (thissize == 0
+		  || TREE_STRING_POINTER (exp) [thissize - 1] != '\0'))
+	    thissize++;
 	  gcc_checking_assert (check_string_literal (exp, size));
 	  assemble_string (TREE_STRING_POINTER (exp), thissize);
 	  break;
@@ -4977,14 +4987,14 @@ output_constant (tree exp, unsigned HOST_WIDE_INT size, unsigned int align,
 	    unsigned int nalign = MIN (align, GET_MODE_ALIGNMENT (inner));
 	    int elt_size = GET_MODE_SIZE (inner);
 	    output_constant (VECTOR_CST_ELT (exp, 0), elt_size, align,
-			     reverse);
+			     reverse, false);
 	    thissize = elt_size;
 	    /* Static constants must have a fixed size.  */
 	    unsigned int nunits = VECTOR_CST_NELTS (exp).to_constant ();
 	    for (unsigned int i = 1; i < nunits; i++)
 	      {
 		output_constant (VECTOR_CST_ELT (exp, i), elt_size, nalign,
-				 reverse);
+				 reverse, false);
 		thissize += elt_size;
 	      }
 	    break;
@@ -5105,8 +5115,8 @@ output_constructor_array_range (oc_local_state *local)
       if (local->val == NULL_TREE)
 	assemble_zeros (fieldsize);
       else
-	fieldsize
-	  = output_constant (local->val, fieldsize, align2, local->reverse);
+	fieldsize = output_constant (local->val, fieldsize, align2,
+				     local->reverse, false);
 
       /* Count its size.  */
       local->total_bytes += fieldsize;
@@ -5201,8 +5211,8 @@ output_constructor_regular_field (oc_local_state *local)
   if (local->val == NULL_TREE)
     assemble_zeros (fieldsize);
   else
-    fieldsize
-      = output_constant (local->val, fieldsize, align2, local->reverse);
+    fieldsize = output_constant (local->val, fieldsize, align2,
+				 local->reverse, false);
 
   /* Count its size.  */
   local->total_bytes += fieldsize;
@@ -7618,8 +7628,8 @@ output_object_block (struct object_block *block)
 	{
 	  HOST_WIDE_INT size;
 	  decl = SYMBOL_REF_DECL (symbol);
-	  assemble_constant_contents
-	       (DECL_INITIAL (decl), XSTR (symbol, 0), DECL_ALIGN (decl));
+	  assemble_constant_contents (DECL_INITIAL (decl), XSTR (symbol, 0),
+				      DECL_ALIGN (decl), false);
 
 	  size = get_constant_size (DECL_INITIAL (decl));
 	  offset += size;
@@ -7636,7 +7646,7 @@ output_object_block (struct object_block *block)
 	{
 	  HOST_WIDE_INT size;
 	  decl = SYMBOL_REF_DECL (symbol);
-	  assemble_variable_contents (decl, XSTR (symbol, 0), false);
+	  assemble_variable_contents (decl, XSTR (symbol, 0), false, false);
 	  size = tree_to_uhwi (DECL_SIZE_UNIT (decl));
 	  offset += size;
 	  if ((flag_sanitize & SANITIZE_ADDRESS)