fix Issue 15831 - Mangle back references to avoid huge symbol names

src/ddmd/dtemplate.d

@@ -8223,123 +8223,10 @@ extern (C++) class TemplateInstance : ScopeDsymbol
      */
     final Identifier genIdent(Objects* args)
     {
-        TemplateDeclaration tempdecl = this.tempdecl.isTemplateDeclaration();
-        assert(tempdecl);
-
         //printf("TemplateInstance.genIdent('%s')\n", tempdecl.ident.toChars());
+        assert(args is tiargs);
         OutBuffer buf;
-
-        const id = tempdecl.ident.toString();
-        // Use "__U" for the symbols declared inside template constraint.
-        const char T = members ? 'T' : 'U';
-        buf.printf("__%c%u%.*s", T, cast(int)id.length, cast(int)id.length, id.ptr);
-
-        size_t nparams = tempdecl.parameters.dim - (tempdecl.isVariadic() ? 1 : 0);
-        for (size_t i = 0; i < args.dim; i++)
-        {
-            RootObject o = (*args)[i];
-            Type ta = isType(o);
-            Expression ea = isExpression(o);
-            Dsymbol sa = isDsymbol(o);
-            Tuple va = isTuple(o);
-            //printf("\to [%d] %p ta %p ea %p sa %p va %p\n", i, o, ta, ea, sa, va);
-            if (i < nparams && (*tempdecl.parameters)[i].specialization())
-                buf.writeByte('H'); // https://issues.dlang.org/show_bug.cgi?id=6574
-            if (ta)
-            {
-                buf.writeByte('T');
-                if (ta.deco)
-                    buf.writestring(ta.deco);
-                else
-                {
-                    debug
-                    {
-                        if (!global.errors)
-                            printf("ta = %d, %s\n", ta.ty, ta.toChars());
-                    }
-                    assert(global.errors);
-                }
-            }
-            else if (ea)
-            {
-                // Don't interpret it yet, it might actually be an alias template parameter.
-                // Only constfold manifest constants, not const/immutable lvalues, see https://issues.dlang.org/show_bug.cgi?id=17339.
-                enum keepLvalue = true;
-                ea = ea.optimize(WANTvalue, keepLvalue);
-                if (ea.op == TOKvar)
-                {
-                    sa = (cast(VarExp)ea).var;
-                    ea = null;
-                    goto Lsa;
-                }
-                if (ea.op == TOKthis)
-                {
-                    sa = (cast(ThisExp)ea).var;
-                    ea = null;
-                    goto Lsa;
-                }
-                if (ea.op == TOKfunction)
-                {
-                    if ((cast(FuncExp)ea).td)
-                        sa = (cast(FuncExp)ea).td;
-                    else
-                        sa = (cast(FuncExp)ea).fd;
-                    ea = null;
-                    goto Lsa;
-                }
-                buf.writeByte('V');
-                if (ea.op == TOKtuple)
-                {
-                    ea.error("tuple is not a valid template value argument");
-                    continue;
-                }
-                // Now that we know it is not an alias, we MUST obtain a value
-                uint olderr = global.errors;
-                ea = ea.ctfeInterpret();
-                if (ea.op == TOKerror || olderr != global.errors)
-                    continue;
-
-                /* Use deco that matches what it would be for a function parameter
-                 */
-                buf.writestring(ea.type.deco);
-                mangleToBuffer(ea, &buf);
-            }
-            else if (sa)
-            {
-            Lsa:
-                buf.writeByte('S');
-                sa = sa.toAlias();
-                Declaration d = sa.isDeclaration();
-                if (d && (!d.type || !d.type.deco))
-                {
-                    error("forward reference of %s %s", d.kind(), d.toChars());
-                    continue;
-                }
-
-                OutBuffer bufsa;
-                mangleToBuffer(sa, &bufsa);
-                auto s = bufsa.peekSlice();
-
-                /* https://issues.dlang.org/show_bug.cgi?id=3043
-                 * If the first character of p is a digit this
-                 * causes ambiguity issues because the digits of the two numbers are adjacent.
-                 * Current demanglers resolve this by trying various places to separate the
-                 * numbers until one gets a successful demangle.
-                 * Unfortunately, fixing this ambiguity will break existing binary
-                 * compatibility and the demanglers, so we'll leave it as is.
-                 */
-                buf.printf("%u%.*s", cast(uint)s.length, cast(int)s.length, s.ptr);
-            }
-            else if (va)
-            {
-                assert(i + 1 == args.dim); // must be last one
-                args = &va.objects;
-                i = -cast(size_t)1;
-            }
-            else
-                assert(0);
-        }
-        buf.writeByte('Z');
+        mangleToBuffer(this, &buf);
         //printf("\tgenIdent = %s\n", buf.peekString());
         return Identifier.idPool(buf.peekSlice());
     }

src/ddmd/toir.d

@@ -415,15 +415,15 @@ int intrinsic_op(FuncDeclaration fd)
         "4math6yl2xp1FNaNbNiNfeeZe",
 
         "4simd10__prefetchFNaNbNiNfxPvhZv",
-        "4simd10__simd_stoFNaNbNiNfE4core4simd3XMMNhG16vNhG16vZNhG16v",
-        "4simd10__simd_stoFNaNbNiNfE4core4simd3XMMdNhG16vZNhG16v",
-        "4simd10__simd_stoFNaNbNiNfE4core4simd3XMMfNhG16vZNhG16v",
-        "4simd6__simdFNaNbNiNfE4core4simd3XMMNhG16vNhG16vZNhG16v",
-        "4simd6__simdFNaNbNiNfE4core4simd3XMMNhG16vNhG16vhZNhG16v",
-        "4simd6__simdFNaNbNiNfE4core4simd3XMMNhG16vZNhG16v",
-        "4simd6__simdFNaNbNiNfE4core4simd3XMMdZNhG16v",
-        "4simd6__simdFNaNbNiNfE4core4simd3XMMfZNhG16v",
-        "4simd9__simd_ibFNaNbNiNfE4core4simd3XMMNhG16vhZNhG16v",
+        "4simd10__simd_stoFNaNbNiNfEQBgQBe3XMMNhG16vQgZQj",
+        "4simd10__simd_stoFNaNbNiNfEQBgQBe3XMMdNhG16vZQh",
+        "4simd10__simd_stoFNaNbNiNfEQBgQBe3XMMfNhG16vZQh",
+        "4simd6__simdFNaNbNiNfEQBbQz3XMMNhG16vQgZQj",
+        "4simd6__simdFNaNbNiNfEQBbQz3XMMNhG16vQghZQk",
+        "4simd6__simdFNaNbNiNfEQBbQz3XMMNhG16vZQh",
+        "4simd6__simdFNaNbNiNfEQBbQz3XMMdZNhG16v",
+        "4simd6__simdFNaNbNiNfEQBbQz3XMMfZNhG16v",
+        "4simd9__simd_ibFNaNbNiNfEQBeQBc3XMMNhG16vhZQi",
 
         "5bitop12volatileLoadFNbNiNfPhZh",
         "5bitop12volatileLoadFNbNiNfPkZk",
@@ -469,15 +469,15 @@ int intrinsic_op(FuncDeclaration fd)
         "4math6yl2xp1FNaNbNiNfeeZe",
 
         "4simd10__prefetchFNaNbNiNfxPvhZv",
-        "4simd10__simd_stoFNaNbNiNfE4core4simd3XMMNhG16vNhG16vZNhG16v",
-        "4simd10__simd_stoFNaNbNiNfE4core4simd3XMMdNhG16vZNhG16v",
-        "4simd10__simd_stoFNaNbNiNfE4core4simd3XMMfNhG16vZNhG16v",
-        "4simd6__simdFNaNbNiNfE4core4simd3XMMNhG16vNhG16vZNhG16v",
-        "4simd6__simdFNaNbNiNfE4core4simd3XMMNhG16vNhG16vhZNhG16v",
-        "4simd6__simdFNaNbNiNfE4core4simd3XMMNhG16vZNhG16v",
-        "4simd6__simdFNaNbNiNfE4core4simd3XMMdZNhG16v",
-        "4simd6__simdFNaNbNiNfE4core4simd3XMMfZNhG16v",
-        "4simd9__simd_ibFNaNbNiNfE4core4simd3XMMNhG16vhZNhG16v",
+        "4simd10__simd_stoFNaNbNiNfEQBgQBe3XMMNhG16vQgZQj",
+        "4simd10__simd_stoFNaNbNiNfEQBgQBe3XMMdNhG16vZQh",
+        "4simd10__simd_stoFNaNbNiNfEQBgQBe3XMMfNhG16vZQh",
+        "4simd6__simdFNaNbNiNfEQBbQz3XMMNhG16vQgZQj",
+        "4simd6__simdFNaNbNiNfEQBbQz3XMMNhG16vQghZQk",
+        "4simd6__simdFNaNbNiNfEQBbQz3XMMNhG16vZQh",
+        "4simd6__simdFNaNbNiNfEQBbQz3XMMdZNhG16v",
+        "4simd6__simdFNaNbNiNfEQBbQz3XMMfZNhG16v",
+        "4simd9__simd_ibFNaNbNiNfEQBeQBc3XMMNhG16vhZQi",
 
         "5bitop12volatileLoadFNbNiNfPhZh",
         "5bitop12volatileLoadFNbNiNfPkZk",

test/compilable/extra-files/json-postscript.sh

@@ -1,10 +1,13 @@
 #!/usr/bin/env bash
 
 grep -v "\"file\" : " ${RESULTS_DIR}/compilable/json.out | grep -v "\"offset\" : " > ${RESULTS_DIR}/compilable/json.out.2
-diff --strip-trailing-cr compilable/extra-files/json.out ${RESULTS_DIR}/compilable/json.out.2
+grep -v "\"deco\" : " ${RESULTS_DIR}/compilable/json.out.2 > ${RESULTS_DIR}/compilable/json.out.3
+grep -v "\"deco\" : " compilable/extra-files/json.out      > ${RESULTS_DIR}/compilable/json.out.4
+
+diff --strip-trailing-cr ${RESULTS_DIR}/compilable/json.out.4 ${RESULTS_DIR}/compilable/json.out.3
 if [ $? -ne 0 ]; then
     exit 1;
 fi
 
-rm ${RESULTS_DIR}/compilable/json.out{,.2}
+rm ${RESULTS_DIR}/compilable/json.out{,.2,.3,.4}
 

test/compilable/test10993.d

@@ -1,5 +1,7 @@
 module test10993;
 
+import core.demangle : demangleType;
+
 auto foo(T)(T a)
 {
 	static immutable typeof(a) q;
@@ -29,5 +31,7 @@ void main()
 	auto y = cast()x;
 	enum mangle_y = typeof(y).mangleof;
 //	pragma(msg, "y  : " ~ mangle_y);
-	static assert (mangle_y == mangle_x[1..$]);
+	enum demangle_x = demangleType(mangle_x);
+	enum demangle_y = demangleType(mangle_y);
+	static assert ("immutable(" ~ demangle_y ~ ")" == demangle_x);
 }

test/compilable/testInference.d

@@ -261,11 +261,13 @@ void test8234()
 /***************************************************/
 // 8504
 
+import core.demangle : demangle;
+
 void foo8504()()
 {
     static assert(typeof(foo8504!()).stringof == "void()");
     static assert(typeof(foo8504!()).mangleof == "FZv");
-    static assert(foo8504!().mangleof == "_D13testInference12__T7foo8504Z7foo8504FZv");
+    static assert(demangle(foo8504!().mangleof) == "void testInference.foo8504!().foo8504()");
 }
 
 auto toDelegate8504a(F)(auto ref F fp) { return fp; }
@@ -277,7 +279,7 @@ void test8504()
 {
     static assert(typeof(foo8504!()).stringof == "pure nothrow @nogc @safe void()");
     static assert(typeof(foo8504!()).mangleof == "FNaNbNiNfZv");
-    static assert(foo8504!().mangleof == "_D13testInference12__T7foo8504Z7foo8504FNaNbNiNfZv");
+    static assert(demangle(foo8504!().mangleof) == "pure nothrow @nogc @safe void testInference.foo8504!().foo8504()");
 
     auto fp1 = toDelegate8504a(&testC8504);
     auto fp2 = toDelegate8504b(&testC8504);

test/runnable/extra-files/test10386.d

@@ -3,9 +3,11 @@ module test10386;
 // import lib.foo.bar;  // ok
 import lib10386.foo;  // linker failure
 
+import imports.testmangle;
+
 void main()
 {
-    static assert(foo.mangleof == "_D8lib103863foo3bar3fooFiZv");
+    static assert(equalDemangle(foo.mangleof, "_D8lib103863foo3bar3fooFiZv"));
     foo(1);
 }
 

test/runnable/imports/testmangle.d

@@ -0,0 +1,66 @@
+// helper for mangling tests with back references
+
+module imports.testmangle;
+
+public import core.demangle : demangle, demangleType;
+
+// detect mangle version
+private
+{
+    struct Detect;
+    Detect* detectMangle(Detect*);
+    void DetectTmpl(T)() {}
+}
+
+pragma(msg,detectMangle.mangleof);
+static if(detectMangle.mangleof == "_D7imports10testmangle12detectMangleFPSQL3H6DetectZQ1e")
+    enum { BackRefs = true, BackRefSymbols = true }
+else static if(detectMangle.mangleof == "_D7imports10testmangle12detectMangleFPSQBlQBg6DetectZQq")
+    enum { BackRefs = true, BackRefSymbols = false }
+else static if(detectMangle.mangleof == "_D7imports10testmangle12detectMangleFPS7imports10testmangle6DetectZPS7imports10testmangle6Detect")
+    enum { BackRefs = false, BackRefSymbols = false }
+else
+    static assert(false, "unknown mangling");
+
+private enum tmplMangle = (DetectTmpl!int).mangleof;
+pragma(msg,tmplMangle);
+static if(tmplMangle[0..40] == "_D7imports10testmangle__T10DetectTmplTiZ")
+    enum HasTemplateLength = false;
+else static if(tmplMangle[0..42] == "_D7imports10testmangle18__T10DetectTmplTiZ")
+    enum HasTemplateLength = true;
+else
+    static assert(false, "unknown mangling");
+
+pragma(msg,BackRefs);
+pragma(msg,BackRefSymbols);
+
+static if (BackRefs)
+{
+    string tl(string s)() { return null; }
+    string id(string s, string r, string r2 = null)() { return BackRefSymbols && r2 !is null ? r2 : r; }
+}
+else
+{
+    string tl(string s)() { return HasTemplateLength ? s : null; }
+    string id(string s, string r, string r2 = null)() { return s; }
+}
+
+bool equalDemangle(string m1, string m2)
+{
+    auto dm1 = demangle(m1);
+    auto dm2 = demangle(m2);
+    return dm1 == dm2;
+}
+
+string unsignedToString(ulong x)
+{
+    string s;
+    s ~= cast(char)('0' + (x % 10));
+    x /= 10;
+    while (x > 0)
+    {
+        s = cast(char)('0' + (x % 10)) ~ s;
+        x /= 10;
+    }
+    return s;
+}

test/runnable/link6574.d

@@ -1,16 +1,18 @@
 // PERMUTE_ARGS:
 module link6574;
 
+import imports.testmangle;
+
 enum Method { A, B, }
 
 int foo(Method method = Method.A)()
 {
-    static assert(foo.mangleof == "_D8link657428__T3fooVE8link65746Methodi0Z3fooFZi");
+    static assert(foo.mangleof == "_D8link6574"~tl!"28"~"__T3fooVE"~id!("8link6574","Qs")~"6Methodi0Z"~id!("3foo","Qs")~"FZi");
     return 10 * foo!method();
 }
 int foo(Method method : Method.A)()
 {
-    static assert(foo.mangleof == "_D8link657429__T3fooHVE8link65746Methodi0Z3fooFZi");
+    static assert(foo.mangleof == "_D8link6574"~tl!"29"~"__T3fooHVE"~id!("8link6574","Qt")~"6Methodi0Z"~id!("3foo","Qt")~"FZi");
     return 2;
 }
 int foo(Method method : Method.B)()
@@ -21,7 +23,7 @@ int foo(Method method : Method.B)()
 
 int bar(Method method = Method.B)()
 {
-    static assert(bar.mangleof == "_D8link657428__T3barVE8link65746Methodi1Z3barFZi");
+    static assert(bar.mangleof == "_D8link6574"~tl!"28"~"__T3barVE"~id!("8link6574","Qs")~"6Methodi1Z"~id!("3bar","Qs")~"FZi");
     return 10 * bar!method();
 }
 int bar(Method method : Method.A)()
@@ -31,7 +33,7 @@ int bar(Method method : Method.A)()
 }
 int bar(Method method : Method.B)()
 {
-    static assert(bar.mangleof == "_D8link657429__T3barHVE8link65746Methodi1Z3barFZi");
+    static assert(bar.mangleof == "_D8link6574"~tl!"29"~"__T3barHVE"~id!("8link6574","Qt")~"6Methodi1Z"~id!("3bar","Qt")~"FZi");
     return 3;
 }