re PR debug/55541 (unable to see local variables due extra lexical block was generated)

	PR debug/55541
	* cp-tree.h (BLOCK_OUTER_CURLY_BRACE_P): Define.
	* decl.c (poplevel): If functionbody, try not to create an extra
	BLOCK for function body and use subblocks as that, if it is non-NULL
	and doesn't have siblings.  Set BLOCK_OUTER_CURLY_BRACE_P flag.
	(outer_curly_brace_block): Use BLOCK_OUTER_CURLY_BRACE_P flag.

	* g++.dg/debug/dwarf2/localclass3.C: Adjust for the extraneous
	DW_TAG_lexical_block removal.
	* g++.dg/debug/dwarf2/redeclaration-1.C: Likewise.
	* g++.dg/guality/pr55541.C: New test.

From-SVN: r220650

3 files changed, 44 insertions, 11 deletions

diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index b66231d..722e926 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,5 +1,12 @@
 2015-02-12  Jakub Jelinek  <jakub@redhat.com>
 
+	PR debug/55541
+	* cp-tree.h (BLOCK_OUTER_CURLY_BRACE_P): Define.
+	* decl.c (poplevel): If functionbody, try not to create an extra
+	BLOCK for function body and use subblocks as that, if it is non-NULL
+	and doesn't have siblings.  Set BLOCK_OUTER_CURLY_BRACE_P flag.
+	(outer_curly_brace_block): Use BLOCK_OUTER_CURLY_BRACE_P flag.
+
 	PR sanitizer/64984
 	* except.c (check_noexcept_r): Return NULL for internal
 	calls.
diff --git a/gcc/cp/cp-tree.h b/gcc/cp/cp-tree.h
index 1176583..65219f1 100644
--- a/gcc/cp/cp-tree.h
+++ b/gcc/cp/cp-tree.h
@@ -84,6 +84,7 @@ c-common.h, not after.
       PACK_EXPANSION_LOCAL_P (in *_PACK_EXPANSION)
       TINFO_HAS_ACCESS_ERRORS (in TEMPLATE_INFO)
       SIZEOF_EXPR_TYPE_P (in SIZEOF_EXPR)
+      BLOCK_OUTER_CURLY_BRACE_P (in BLOCK)
    1: IDENTIFIER_VIRTUAL_P (in IDENTIFIER_NODE)
       TI_PENDING_TEMPLATE_FLAG.
       TEMPLATE_PARMS_FOR_INLINE.
@@ -326,6 +327,9 @@ typedef struct ptrmem_cst * ptrmem_cst_t;
 #define STATEMENT_LIST_TRY_BLOCK(NODE) \
   TREE_LANG_FLAG_2 (STATEMENT_LIST_CHECK (NODE))
 
+/* Mark the outer curly brace BLOCK.  */
+#define BLOCK_OUTER_CURLY_BRACE_P(NODE)	TREE_LANG_FLAG_0 (BLOCK_CHECK (NODE))
+
 /* Nonzero if this statement should be considered a full-expression,
    i.e., if temporaries created during this statement should have
    their destructors run at the end of this statement.  */
diff --git a/gcc/cp/decl.c b/gcc/cp/decl.c
index d2b0814..50b0624 100644
--- a/gcc/cp/decl.c
+++ b/gcc/cp/decl.c
@@ -610,7 +610,10 @@ poplevel (int keep, int reverse, int functionbody)
      or if this level is a function body,
      create a BLOCK to record them for the life of this function.  */
   block = NULL_TREE;
-  if (keep == 1 || functionbody)
+  /* Avoid function body block if possible.  */
+  if (functionbody && subblocks && BLOCK_CHAIN (subblocks) == NULL_TREE)
+    keep = 0;
+  else if (keep == 1 || functionbody)
     block = make_node (BLOCK);
   if (block != NULL_TREE)
     {
@@ -793,11 +796,16 @@ poplevel (int keep, int reverse, int functionbody)
      check over all the labels.  */
   if (functionbody)
     {
-      /* Since this is the top level block of a function, the vars are
-	 the function's parameters.  Don't leave them in the BLOCK
-	 because they are found in the FUNCTION_DECL instead.  */
-      BLOCK_VARS (block) = 0;
-      pop_labels (block);
+      if (block)
+	{
+	  /* Since this is the top level block of a function, the vars are
+	     the function's parameters.  Don't leave them in the BLOCK
+	     because they are found in the FUNCTION_DECL instead.  */
+	  BLOCK_VARS (block) = 0;
+	  pop_labels (block);
+	}
+      else
+	pop_labels (subblocks);
     }
 
   kind = current_binding_level->kind;
@@ -819,7 +827,17 @@ poplevel (int keep, int reverse, int functionbody)
       /* The current function is being defined, so its DECL_INITIAL
 	 should be error_mark_node.  */
       gcc_assert (DECL_INITIAL (current_function_decl) == error_mark_node);
-      DECL_INITIAL (current_function_decl) = block;
+      DECL_INITIAL (current_function_decl) = block ? block : subblocks;
+      if (subblocks)
+	{
+	  if (FUNCTION_NEEDS_BODY_BLOCK (current_function_decl))
+	    {
+	      if (BLOCK_SUBBLOCKS (subblocks))
+		BLOCK_OUTER_CURLY_BRACE_P (BLOCK_SUBBLOCKS (subblocks)) = 1;
+	    }
+	  else
+	    BLOCK_OUTER_CURLY_BRACE_P (subblocks) = 1;
+	}
     }
   else if (block)
     current_binding_level->blocks
@@ -14053,10 +14071,14 @@ finish_function_body (tree compstmt)
 tree
 outer_curly_brace_block (tree fndecl)
 {
-  tree block = BLOCK_SUBBLOCKS (DECL_INITIAL (fndecl));
-  if (FUNCTION_NEEDS_BODY_BLOCK (current_function_decl))
-    /* Skip the artificial function body block.  */
-    block = BLOCK_SUBBLOCKS (block);
+  tree block = DECL_INITIAL (fndecl);
+  if (BLOCK_OUTER_CURLY_BRACE_P (block))
+    return block;
+  block = BLOCK_SUBBLOCKS (block);
+  if (BLOCK_OUTER_CURLY_BRACE_P (block))
+    return block;
+  block = BLOCK_SUBBLOCKS (block);
+  gcc_assert (BLOCK_OUTER_CURLY_BRACE_P (block));
   return block;
 }