From 65851d65fb36e847a9b8ef3b0519f06d29865a14 Mon Sep 17 00:00:00 2001
From: Nathan Sidwell <nathan@acm.org>
Date: Tue, 8 Mar 2022 10:53:39 -0800
Subject: [PATCH] demangler: Reorganize for module demangling

Module demangling requires some changes in how substitutions are
handled.  This adjusts things to make that possible.

	libiberty/
	* cp-demangle.c (d_name): Add SUBSTABLE parameter,
	push substitution if requested. Adjust unscoped name handling.
	(d_prefix): Reorder main loop. Adjust all calls.
	(d_unqualified_name): Add SCOPE parameter, create qualified
	name here. Adjust all calls.
	(cplus_demangle_type): Do not handle 'S' here, leave all
	to d_class_enum_type.
	(d_class_enum_type): Add SUBSTABLE parameter.
---
 libiberty/cp-demangle.c | 224 +++++++++++++++-------------------------
 1 file changed, 84 insertions(+), 140 deletions(-)

diff --git a/libiberty/cp-demangle.c b/libiberty/cp-demangle.c
index fc618fa7383..cf451c5aff2 100644
--- a/libiberty/cp-demangle.c
+++ b/libiberty/cp-demangle.c
@@ -425,13 +425,14 @@ is_ctor_dtor_or_conversion (struct demangle_component *);
 
 static struct demangle_component *d_encoding (struct d_info *, int);
 
-static struct demangle_component *d_name (struct d_info *);
+static struct demangle_component *d_name (struct d_info *, int substable);
 
 static struct demangle_component *d_nested_name (struct d_info *);
 
 static struct demangle_component *d_prefix (struct d_info *, int);
 
-static struct demangle_component *d_unqualified_name (struct d_info *);
+static struct demangle_component *d_unqualified_name (struct d_info *,
+						      struct demangle_component *scope);
 
 static struct demangle_component *d_source_name (struct d_info *);
 
@@ -462,7 +463,7 @@ static struct demangle_component *
 d_bare_function_type (struct d_info *, int);
 
 static struct demangle_component *
-d_class_enum_type (struct d_info *);
+d_class_enum_type (struct d_info *, int);
 
 static struct demangle_component *d_array_type (struct d_info *);
 
@@ -1323,7 +1324,7 @@ d_encoding (struct d_info *di, int top_level)
     dc = d_special_name (di);
   else
     {
-      dc = d_name (di);
+      dc = d_name (di, 0);
 
       if (!dc)
 	/* Failed already.  */;
@@ -1417,80 +1418,64 @@ d_abi_tags (struct d_info *di, struct demangle_component *dc)
 */
 
 static struct demangle_component *
-d_name (struct d_info *di)
+d_name (struct d_info *di, int substable)
 {
   char peek = d_peek_char (di);
-  struct demangle_component *dc;
+  struct demangle_component *dc = NULL;
+  int subst = 0;
 
   switch (peek)
     {
     case 'N':
-      return d_nested_name (di);
+      dc = d_nested_name (di);
+      break;
 
     case 'Z':
-      return d_local_name (di);
+      dc = d_local_name (di);
+      break;
 
     case 'U':
-      return d_unqualified_name (di);
+      dc = d_unqualified_name (di, NULL);
+      break;
 
     case 'S':
       {
-	int subst;
-
-	if (d_peek_next_char (di) != 't')
-	  {
-	    dc = d_substitution (di, 0);
-	    subst = 1;
-	  }
-	else
+	if (d_peek_next_char (di) == 't')
 	  {
 	    d_advance (di, 2);
-	    dc = d_make_comp (di, DEMANGLE_COMPONENT_QUAL_NAME,
-			      d_make_name (di, "std", 3),
-			      d_unqualified_name (di));
+	    dc = d_make_name (di, "std", 3);
 	    di->expansion += 3;
-	    subst = 0;
-	  }
-
-	if (d_peek_char (di) != 'I')
-	  {
-	    /* The grammar does not permit this case to occur if we
-	       called d_substitution() above (i.e., subst == 1).  We
-	       don't bother to check.  */
 	  }
 	else
 	  {
-	    /* This is <template-args>, which means that we just saw
-	       <unscoped-template-name>, which is a substitution
-	       candidate if we didn't just get it from a
-	       substitution.  */
-	    if (! subst)
-	      {
-		if (! d_add_substitution (di, dc))
-		  return NULL;
-	      }
-	    dc = d_make_comp (di, DEMANGLE_COMPONENT_TEMPLATE, dc,
-			      d_template_args (di));
+	    dc = d_substitution (di, 0);
+	    if (!dc)
+	      return NULL;
+	    subst = 1;
 	  }
-
-	return dc;
       }
+      /* FALLTHROUGH */
 
     case 'L':
     default:
-      dc = d_unqualified_name (di);
+      if (!subst)
+	dc = d_unqualified_name (di, dc);
       if (d_peek_char (di) == 'I')
 	{
 	  /* This is <template-args>, which means that we just saw
 	     <unscoped-template-name>, which is a substitution
 	     candidate.  */
-	  if (! d_add_substitution (di, dc))
+	  if (!subst && !d_add_substitution (di, dc))
 	    return NULL;
 	  dc = d_make_comp (di, DEMANGLE_COMPONENT_TEMPLATE, dc,
 			    d_template_args (di));
+	  subst = 0;
 	}
-      return dc;
+      break;
     }
+  if (substable && !subst && !d_add_substitution (di, dc))
+    return NULL;
+  return dc;
 }
 
 /* <nested-name> ::= N [<CV-qualifiers>] [<ref-qualifier>] <prefix> <unqualified-name> E
@@ -1546,54 +1531,51 @@ d_nested_name (struct d_info *di)
    if not (in an unresolved-name).  */
 
 static struct demangle_component *
-d_prefix (struct d_info *di, int subst)
+d_prefix (struct d_info *di, int substable)
 {
   struct demangle_component *ret = NULL;
 
-  while (1)
+  for (;;)
     {
-      char peek;
-      enum demangle_component_type comb_type;
-      struct demangle_component *dc;
-
-      peek = d_peek_char (di);
-      if (peek == '\0')
-	return NULL;
+      char peek = d_peek_char (di);
 
       /* The older code accepts a <local-name> here, but I don't see
 	 that in the grammar.  The older code does not accept a
 	 <template-param> here.  */
 
-      comb_type = DEMANGLE_COMPONENT_QUAL_NAME;
-      if (peek == 'D')
+      if (peek == 'D'
+	  && (d_peek_next_char (di) == 'T'
+	      || d_peek_next_char (di) == 't'))
 	{
-	  char peek2 = d_peek_next_char (di);
-	  if (peek2 == 'T' || peek2 == 't')
-	    /* Decltype.  */
-	    dc = cplus_demangle_type (di);
-	  else
-	    /* Destructor name.  */
-	    dc = d_unqualified_name (di);
+	  /* Decltype.  */
+	  if (ret)
+	    return NULL;
+	  ret = cplus_demangle_type (di);
 	}
-      else if (IS_DIGIT (peek)
-	  || IS_LOWER (peek)
-	  || peek == 'C'
-	  || peek == 'U'
-	  || peek == 'L')
-	dc = d_unqualified_name (di);
       else if (peek == 'S')
-	dc = d_substitution (di, 1);
+	{
+	  if (ret)
+	    return NULL;
+	  ret = d_substitution (di, 1);
+	  if (!ret)
+	    return NULL;
+	  continue;
+	}
       else if (peek == 'I')
 	{
 	  if (ret == NULL)
 	    return NULL;
-	  comb_type = DEMANGLE_COMPONENT_TEMPLATE;
-	  dc = d_template_args (di);
+	  struct demangle_component *dc = d_template_args (di);
+	  if (!dc)
+	    return NULL;
+	  ret = d_make_comp (di, DEMANGLE_COMPONENT_TEMPLATE, ret, dc);
 	}
       else if (peek == 'T')
-	dc = d_template_param (di);
-      else if (peek == 'E')
-	return ret;
+	{
+	  if (ret)
+	    return NULL;
+	  ret = d_template_param (di);
+	}
       else if (peek == 'M')
 	{
 	  /* Initializer scope for a lambda.  We don't need to represent
@@ -1602,22 +1584,21 @@ d_prefix (struct d_info *di, int subst)
 	  if (ret == NULL)
 	    return NULL;
 	  d_advance (di, 1);
-	  continue;
 	}
       else
+	ret = d_unqualified_name (di, ret);
+
+      if (!ret)
+	break;
+
+      if (d_peek_char (di) == 'E')
+	break;
+
+      if (substable && !d_add_substitution (di, ret))
 	return NULL;
-
-      if (ret == NULL)
-	ret = dc;
-      else
-	ret = d_make_comp (di, comb_type, ret, dc);
-
-      if (peek != 'S' && d_peek_char (di) != 'E' && subst)
-	{
-	  if (! d_add_substitution (di, ret))
-	    return NULL;
-	}
     }
+
+  return ret;
 }
 
 /* <unqualified-name> ::= <operator-name> [<abi-tags>]
@@ -1629,7 +1610,7 @@ d_prefix (struct d_info *di, int subst)
 */
 
 static struct demangle_component *
-d_unqualified_name (struct d_info *di)
+d_unqualified_name (struct d_info *di, struct demangle_component *scope)
 {
   struct demangle_component *ret;
   char peek;
@@ -1709,6 +1690,9 @@ d_unqualified_name (struct d_info *di)
 
   if (d_peek_char (di) == 'B')
     ret = d_abi_tags (di, ret);
+  if (scope)
+    ret = d_make_comp (di, DEMANGLE_COMPONENT_QUAL_NAME, scope, ret);
+
   return ret;
 }
 
@@ -2149,11 +2133,11 @@ d_special_name (struct d_info *di)
 
 	case 'H':
 	  return d_make_comp (di, DEMANGLE_COMPONENT_TLS_INIT,
-			      d_name (di), NULL);
+			      d_name (di, 0), NULL);
 
 	case 'W':
 	  return d_make_comp (di, DEMANGLE_COMPONENT_TLS_WRAPPER,
-			      d_name (di), NULL);
+			      d_name (di, 0), NULL);
 
 	case 'A':
 	  return d_make_comp (di, DEMANGLE_COMPONENT_TPARM_OBJ,
@@ -2169,11 +2153,11 @@ d_special_name (struct d_info *di)
 	{
 	case 'V':
 	  return d_make_comp (di, DEMANGLE_COMPONENT_GUARD,
-			      d_name (di), NULL);
+			      d_name (di, 0), NULL);
 
 	case 'R':
 	  {
-	    struct demangle_component *name = d_name (di);
+	    struct demangle_component *name = d_name (di, 0);
 	    return d_make_comp (di, DEMANGLE_COMPONENT_REFTEMP, name,
 				d_number_component (di));
 	  }
@@ -2504,13 +2488,6 @@ cplus_demangle_type (struct d_info *di)
       ret = d_function_type (di);
       break;
 
-    case '0': case '1': case '2': case '3': case '4':
-    case '5': case '6': case '7': case '8': case '9':
-    case 'N':
-    case 'Z':
-      ret = d_class_enum_type (di);
-      break;
-
     case 'A':
       ret = d_array_type (di);
       break;
@@ -2581,39 +2558,6 @@ cplus_demangle_type (struct d_info *di)
 	}
       break;
 
-    case 'S':
-      /* If this is a special substitution, then it is the start of
-	 <class-enum-type>.  */
-      {
-	char peek_next;
-
-	peek_next = d_peek_next_char (di);
-	if (IS_DIGIT (peek_next)
-	    || peek_next == '_'
-	    || IS_UPPER (peek_next))
-	  {
-	    ret = d_substitution (di, 0);
-	    /* The substituted name may have been a template name and
-	       may be followed by tepmlate args.  */
-	    if (d_peek_char (di) == 'I')
-	      ret = d_make_comp (di, DEMANGLE_COMPONENT_TEMPLATE, ret,
-				 d_template_args (di));
-	    else
-	      can_subst = 0;
-	  }
-	else
-	  {
-	    ret = d_class_enum_type (di);
-	    /* If the substitution was a complete type, then it is not
-	       a new substitution candidate.  However, if the
-	       substitution was followed by template arguments, then
-	       the whole thing is a substitution candidate.  */
-	    if (ret != NULL && ret->type == DEMANGLE_COMPONENT_SUB_STD)
-	      can_subst = 0;
-	  }
-      }
-      break;
-
     case 'O':
       d_advance (di, 1);
       ret = d_make_comp (di, DEMANGLE_COMPONENT_RVALUE_REFERENCE,
@@ -2754,7 +2698,7 @@ cplus_demangle_type (struct d_info *di)
       break;
 
     default:
-      return NULL;
+      return d_class_enum_type (di, 1);
     }
 
   if (can_subst)
@@ -3027,9 +2971,9 @@ d_bare_function_type (struct d_info *di, int has_return_type)
 /* <class-enum-type> ::= <name>  */
 
 static struct demangle_component *
-d_class_enum_type (struct d_info *di)
+d_class_enum_type (struct d_info *di, int substable)
 {
-  return d_name (di);
+  return d_name (di, substable);
 }
 
 /* <array-type> ::= A <(positive dimension) number> _ <(element) type>
@@ -3358,11 +3302,11 @@ d_unresolved_name (struct d_info *di)
     }
   else
     type = cplus_demangle_type (di);
-  name = d_unqualified_name (di);
+  name = d_unqualified_name (di, type);
   if (d_peek_char (di) == 'I')
     name = d_make_comp (di, DEMANGLE_COMPONENT_TEMPLATE, name,
 			d_template_args (di));
-  return d_make_comp (di, DEMANGLE_COMPONENT_QUAL_NAME, type, name);
+  return name;
 }
 
 /* <expression> ::= <(unary) operator-name> <expression>
@@ -3431,7 +3375,7 @@ d_expression_1 (struct d_info *di)
 	/* operator-function-id, i.e. operator+(t).  */
 	d_advance (di, 2);
 
-      name = d_unqualified_name (di);
+      name = d_unqualified_name (di, NULL);
       if (name == NULL)
 	return NULL;
       if (d_peek_char (di) == 'I')
@@ -3539,7 +3483,7 @@ d_expression_1 (struct d_info *di)
 	      /* fold-expression.  */
 	      left = d_operator_name (di);
 	    else if (!strcmp (code, "di"))
-	      left = d_unqualified_name (di);
+	      left = d_unqualified_name (di, NULL);
 	    else
 	      left = d_expression_1 (di);
 	    if (!strcmp (code, "cl"))
@@ -3557,7 +3501,7 @@ d_expression_1 (struct d_info *di)
 		       d_unqualified_name rather than d_expression_1 here for
 		       old mangled names that didn't add 'on' before operator
 		       names.  */
-		    right = d_unqualified_name (di);
+		    right = d_unqualified_name (di, NULL);
 		    if (d_peek_char (di) == 'I')
 		      right = d_make_comp (di, DEMANGLE_COMPONENT_TEMPLATE,
 					   right, d_template_args (di));
@@ -3767,7 +3711,7 @@ d_local_name (struct d_info *di)
 	    return NULL;
 	}
 
-      name = d_name (di);
+      name = d_name (di, 0);
 
       if (name
 	  /* Lambdas and unnamed types have internal discriminators
-- 
2.30.2

