[gcc r12-3215] libiberty: Add support for demangling D function literals as template value parameters

[Iain Buclaw <ibuclaw@gcc.gnu.org>]

https://gcc.gnu.org/g:34f3e0657a1fa976d989b22d18b3b2adf6ddd59b

commit r12-3215-g34f3e0657a1fa976d989b22d18b3b2adf6ddd59b
Author: Iain Buclaw <ibuclaw@gdcproject.org>
Date:   Sun Aug 29 20:04:24 2021 +0200

    libiberty: Add support for demangling D function literals as template value parameters
    
    The D language now allows instantiating templates using struct literals
    that have function literal fields as a value argument.
    
    libiberty/ChangeLog:
    
            * d-demangle.c (dlang_parse_arrayliteral): Add 'info' parameter.
            (dlang_parse_assocarray): Likewise.
            (dlang_parse_structlit): Likewise.
            (dlang_value): Likewise.  Handle function literal symbols.
            (dlang_template_args): Pass 'info' to dlang_value.
            * testsuite/d-demangle-expected: Add new test.

Diff:
---
 libiberty/d-demangle.c                  | 40 ++++++++++++++++++++++-----------
 libiberty/testsuite/d-demangle-expected |  4 ++++
 2 files changed, 31 insertions(+), 13 deletions(-)

diff --git a/libiberty/d-demangle.c b/libiberty/d-demangle.c
index c34f91843de..d74cf47b1a9 100644
--- a/libiberty/d-demangle.c
+++ b/libiberty/d-demangle.c
@@ -191,7 +191,8 @@ static const char *dlang_function_args (string *, const char *,
 
 static const char *dlang_type (string *, const char *, struct dlang_info *);
 
-static const char *dlang_value (string *, const char *, const char *, char);
+static const char *dlang_value (string *, const char *, const char *, char,
+				struct dlang_info *);
 
 static const char *dlang_parse_qualified (string *, const char *,
 					  struct dlang_info *, int);
@@ -1386,7 +1387,8 @@ dlang_parse_string (string *decl, const char *mangled)
 /* Extract the static array value from MANGLED and append it to DECL.
    Return the remaining string on success or NULL on failure.  */
 static const char *
-dlang_parse_arrayliteral (string *decl, const char *mangled)
+dlang_parse_arrayliteral (string *decl, const char *mangled,
+			  struct dlang_info *info)
 {
   unsigned long elements;
 
@@ -1397,7 +1399,7 @@ dlang_parse_arrayliteral (string *decl, const char *mangled)
   string_append (decl, "[");
   while (elements--)
     {
-      mangled = dlang_value (decl, mangled, NULL, '\0');
+      mangled = dlang_value (decl, mangled, NULL, '\0', info);
       if (mangled == NULL)
 	return NULL;
 
@@ -1412,7 +1414,8 @@ dlang_parse_arrayliteral (string *decl, const char *mangled)
 /* Extract the associative array value from MANGLED and append it to DECL.
    Return the remaining string on success or NULL on failure.  */
 static const char *
-dlang_parse_assocarray (string *decl, const char *mangled)
+dlang_parse_assocarray (string *decl, const char *mangled,
+			struct dlang_info *info)
 {
   unsigned long elements;
 
@@ -1423,12 +1426,12 @@ dlang_parse_assocarray (string *decl, const char *mangled)
   string_append (decl, "[");
   while (elements--)
     {
-      mangled = dlang_value (decl, mangled, NULL, '\0');
+      mangled = dlang_value (decl, mangled, NULL, '\0', info);
       if (mangled == NULL)
 	return NULL;
 
       string_append (decl, ":");
-      mangled = dlang_value (decl, mangled, NULL, '\0');
+      mangled = dlang_value (decl, mangled, NULL, '\0', info);
       if (mangled == NULL)
 	return NULL;
 
@@ -1443,7 +1446,8 @@ dlang_parse_assocarray (string *decl, const char *mangled)
 /* Extract the struct literal value for NAME from MANGLED and append it to DECL.
    Return the remaining string on success or NULL on failure.  */
 static const char *
-dlang_parse_structlit (string *decl, const char *mangled, const char *name)
+dlang_parse_structlit (string *decl, const char *mangled, const char *name,
+		       struct dlang_info *info)
 {
   unsigned long args;
 
@@ -1457,7 +1461,7 @@ dlang_parse_structlit (string *decl, const char *mangled, const char *name)
   string_append (decl, "(");
   while (args--)
     {
-      mangled = dlang_value (decl, mangled, NULL, '\0');
+      mangled = dlang_value (decl, mangled, NULL, '\0', info);
       if (mangled == NULL)
 	return NULL;
 
@@ -1472,7 +1476,8 @@ dlang_parse_structlit (string *decl, const char *mangled, const char *name)
 /* Extract the value from MANGLED and append it to DECL.
    Return the remaining string on success or NULL on failure.  */
 static const char *
-dlang_value (string *decl, const char *mangled, const char *name, char type)
+dlang_value (string *decl, const char *mangled, const char *name, char type,
+	     struct dlang_info *info)
 {
   if (mangled == NULL || *mangled == '\0')
     return NULL;
@@ -1533,15 +1538,24 @@ dlang_value (string *decl, const char *mangled, const char *name, char type)
     case 'A':
       mangled++;
       if (type == 'H')
-	mangled = dlang_parse_assocarray (decl, mangled);
+	mangled = dlang_parse_assocarray (decl, mangled, info);
       else
-	mangled = dlang_parse_arrayliteral (decl, mangled);
+	mangled = dlang_parse_arrayliteral (decl, mangled, info);
       break;
 
       /* Struct values.  */
     case 'S':
       mangled++;
-      mangled = dlang_parse_structlit (decl, mangled, name);
+      mangled = dlang_parse_structlit (decl, mangled, name, info);
+      break;
+
+      /* Function literal symbol.  */
+    case 'f':
+      mangled++;
+      if (strncmp (mangled, "_D", 2) != 0
+	  || !dlang_symbol_name_p (mangled + 2, info))
+	return NULL;
+      mangled = dlang_parse_mangle (decl, mangled, info);
       break;
 
     default:
@@ -1814,7 +1828,7 @@ dlang_template_args (string *decl, const char *mangled, struct dlang_info *info)
 	  string_need (&name, 1);
 	  *(name.p) = '\0';
 
-	  mangled = dlang_value (decl, mangled, name.b, type);
+	  mangled = dlang_value (decl, mangled, name.b, type, info);
 	  string_delete (&name);
 	  break;
 	}
diff --git a/libiberty/testsuite/d-demangle-expected b/libiberty/testsuite/d-demangle-expected
index 00036e7810a..87ed8d330a8 100644
--- a/libiberty/testsuite/d-demangle-expected
+++ b/libiberty/testsuite/d-demangle-expected
@@ -1418,3 +1418,7 @@ std.algorithm.iteration.FilterResult!(std.typecons.Tuple!(int, "a", int, "b", in
 --format=dlang
 _D3std3uni__T6toCaseS_DQvQt12toLowerIndexFNaNbNiNewZtVii1043S_DQCjQCi10toLowerTabFNaNbNiNemZwSQDo5ascii7toLowerTAyaZQDzFNaNeQmZ14__foreachbody2MFNaNeKmKwZ14__foreachbody3MFNaNeKwZi
 std.uni.toCase!(std.uni.toLowerIndex(dchar), 1043, std.uni.toLowerTab(ulong), std.ascii.toLower, immutable(char)[]).toCase(immutable(char)[]).__foreachbody2(ref ulong, ref dchar).__foreachbody3(ref dchar)
+#
+--format=dlang
+_D6mangle__T8fun21753VSQv6S21753S1f_DQBj10__lambda71MFNaNbNiNfZvZQCbQp
+mangle.fun21753!(mangle.S21753(mangle.__lambda71())).fun21753