fix issue 18984 - Debugging stack struct's which are returned causes …

…incorrect debuginfo. change the names of the hidden return value and the NRVO variable
dlang · Jun 19, 2018 · b3c9c56 · b3c9c56
1 parent f95b301
commit b3c9c56
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Showing 3 changed files with 71 additions and 10 deletions.
diff --git a/src/dmd/glue.d b/src/dmd/glue.d
@@ -917,8 +917,15 @@ void FuncDeclaration_toObjFile(FuncDeclaration fd, bool multiobj)
         char[5+4+1] hiddenparam = void;
         __gshared int hiddenparami;    // how many we've generated so far
 
-        sprintf(hiddenparam.ptr,"__HID%d",++hiddenparami);
-        shidden = symbol_name(hiddenparam.ptr,SCparameter,thidden);
+        const(char)* name;
+        if (fd.nrvo_can && fd.nrvo_var)
+            name = fd.nrvo_var.ident.toChars();
+        else
+        {
+            sprintf(hiddenparam.ptr, "__HID%d", ++hiddenparami);
+            name = hiddenparam.ptr;
+        }
+        shidden = symbol_name(name, SCparameter, thidden);
         shidden.Sflags |= SFLtrue | SFLfree;
         if (fd.nrvo_can && fd.nrvo_var && fd.nrvo_var.nestedrefs.dim)
             type_setcv(&shidden.Stype, shidden.Stype.Tty | mTYvolatile);

diff --git a/src/dmd/tocsym.d b/src/dmd/tocsym.d
@@ -137,24 +137,35 @@ Symbol *toSymbol(Dsymbol s)
             //printf("VarDeclaration.toSymbol(%s)\n", vd.toChars());
             assert(!vd.needThis());
 
-            Symbol *s;
+            const(char)[] id;
+            import dmd.root.outbuffer : OutBuffer;
+            OutBuffer buf;
+            bool isNRVO = false;
             if (vd.isDataseg())
             {
-                import dmd.root.outbuffer : OutBuffer;
-                OutBuffer buf;
                 mangleToBuffer(vd, &buf);
-                const length = buf.offset;
-                const id = buf.peekString();
-                s = symbol_calloc(id, cast(uint)length);
+                id = buf.peekString()[0..buf.offset]; // symbol_calloc needs zero termination
             }
             else
             {
-                const id = vd.ident.toChars();
-                s = symbol_calloc(id, cast(uint)strlen(id));
+                id = vd.ident.toString();
+                if (FuncDeclaration fd = vd.toParent2().isFuncDeclaration())
+                {
+                    if (fd.nrvo_can && fd.nrvo_var == vd)
+                    {
+                        buf.writestring("__nrvo_");
+                        buf.writestring(id);
+                        id = buf.peekString()[0..buf.offset]; // symbol_calloc needs zero termination
+                        isNRVO = true;
+                    }
+                }
             }
+            Symbol *s = symbol_calloc(id.ptr, cast(uint)id.length);
             s.Salignment = vd.alignment;
             if (vd.storage_class & STC.temp)
                 s.Sflags |= SFLartifical;
+            if (isNRVO)
+                s.Sflags |= SFLnodebug;
 
             TYPE *t;
             if (vd.storage_class & (STC.out_ | STC.ref_))

diff --git a/test/runnable/testpdb.d b/test/runnable/testpdb.d
@@ -39,6 +39,8 @@ void main(string[] args)
 
         testLineNumbers(session, globals);
 
+        S18984 s = test18984(session, globals);
+
         source.Release();
         session.Release();
         globals.Release();
@@ -87,6 +89,47 @@ void testLineNumbers(IDiaSession session, IDiaSymbol globals)
     assert(codeByte == 0x48 || codeByte == 0x5d || codeByte == 0xc3); // should be one of "mov rsp,rbp", "pop rbp" or "ret"
 }
 
+///////////////////////////////////////////////
+// https://issues.dlang.org/show_bug.cgi?id=18984
+// Debugging stack struct's which are returned causes incorrect debuginfo
+
+struct S18984
+{
+    int a, b, c;
+}
+
+S18984 test18984(IDiaSession session, IDiaSymbol globals)
+{
+    enum funcName = "testpdb.test18984";
+    IDiaSymbol funcsym = searchSymbol(globals, funcName);
+    funcsym || assert(false, funcName ~ " not found");
+    IDiaEnumSymbols enumSymbols;
+    HRESULT hr = funcsym.findChildren(SymTagEnum.SymTagNull, "s", NameSearchOptions.nsfCaseSensitive, &enumSymbols);
+    enumSymbols || assert(false, funcName ~ " no children");
+    ULONG fetched;
+    IDiaSymbol symbol;
+    enumSymbols.Next(1, &symbol, &fetched) == S_OK || assert(false, funcName ~ " no children");
+    symbol || assert(false, funcName ~ " no child symbol");
+    assert(enumSymbols);
+    DWORD loc;
+    symbol.get_locationType(&loc) == S_OK || assert(false, funcName ~ " no location type");
+    loc == LocationType.LocIsRegRel || assert(false, funcName ~ " 's' not relative to register");
+    LONG offset;
+    symbol.get_offset(&offset) == S_OK || assert(false, funcName ~ " cannot get variable offset");
+    version(Win64)
+        offset > 0 || assert(false, funcName ~ " 's' not pointing to hidden argument");
+    else // Win32 passes hidden argument in EAX, which is stored to [EBP-4] on function entry
+        offset == -4 || assert(false, funcName ~ " 's' not pointing to hidden argument");
+
+    symbol.Release();
+    enumSymbols.Release();
+
+    S18984 s = S18984(1, 2, 3);
+    s.a = 4;
+    return s; // NRVO
+}
+
+///////////////////////////////////////////////
 import core.stdc.stdio;
 import core.stdc.wchar_;