Changeset 1499:df11cdec45a2

Timestamp:

06/14/09 13:49:58 (3 years ago)

Author:

Christian Kamm <kamm incasoftware de>

branch:

default

Message:

Another shot at fixing the issues with (constant) struct literals and their addresses. See DMD2682, #218, #324.

The idea is to separate the notion of const from 'this variable can always be
replaced with its initializer' in the frontend. To do that, I introduced
Declaration::isSameAsInitializer, which is overridden in VarDeclaration? to
return false for constants that have a struct literal initializer.

So

const S s = S(5);
void foo() { auto ps = &s; }
// is no longer replaced by
void foo() { auto ps = &(S(5)); }

To make taking the address of a struct constant with a struct-initializer
outside of function scope possible, I made sure that AddrExp::optimize doesn't
try to run the argument's optimization with WANTinterpret - that'd again
replace the constant with a struct literal temporary.

Files:

• dmd/declaration.c (modified) (1 diff)
• dmd/declaration.h (modified) (2 diffs)
• dmd/expression.c (modified) (5 diffs)
• dmd/expression.h (modified) (1 diff)
• dmd/mtype.c (modified) (4 diffs)
• dmd/optimize.c (modified) (1 diff)
• tests/mini/conststructliteral.d (added)

dmd/declaration.c

@@ -1214 +1214 @@
-}
-
+int VarDeclaration::isSameAsInitializer()
+{
+    if (init && init->isExpInitializer() && 
+        init->isExpInitializer()->exp->op == TOKstructliteral)
+        return 0;
+    return isConst();
+}
+
-/******************************************
- * If a variable has an auto destructor call, return call for it.

dmd/declaration.h

@@ -136 +136 @@
-    int isDeprecated()   { return storage_class & STCdeprecated; }
-    int isOverride()     { return storage_class & STCoverride; }
+    
+    virtual int isSameAsInitializer() { return isConst(); };
-
-    int isIn()    { return storage_class & STCin; }
@@ -283 +285 @@
-    void checkNestedReference(Scope *sc, Loc loc);
-    Dsymbol *toAlias();
+    
+    virtual int isSameAsInitializer();
-
-#if IN_DMD

dmd/expression.c

@@ -2114 +2114 @@
-        }
-    }
-Const
+SameAsInitializer
-    {
-        if (v->init)
@@ -3243 +3243 @@
-#endif
-
-/*
-Removed in LDC. See declaration.
-Expression *StructLiteralExp::toLvalue(Scope *sc, Expression *e)
-{
-    return this;
-}
-*/
-
-
@@ -3950 +3947 @@
-    if (v)
-    {
-Const
+SameAsInitializer
-    {
-        ExpInitializer *ei = v->init->isExpInitializer();
@@ -5356 +5353 @@
-        }
-        type = v->type;
-Const
+SameAsInitializer
-        {
-            if (v->init)
@@ -5615 +5612 @@
-
-        VarDeclaration *v = var->isVarDeclaration();
-Const
+SameAsInitializer
-        {   ExpInitializer *ei = v->getExpInitializer();
-        if (ei)

dmd/expression.h

@@ -510 +510 @@
-    Expression *optimize(int result);
-    Expression *interpret(InterState *istate);
-
-
-
+
-
-    int inlineCost(InlineCostState *ics);

dmd/mtype.c

@@ -3410 +3410 @@
-        if (v && id == Id::length)
-        {
-Const
+SameAsInitializer
-            {   e = v->getExpInitializer()->exp;
-            }
@@ -3457 +3457 @@
-    {
-        // It's not a type, it's an expression
-Const
+SameAsInitializer
-        {
-        ExpInitializer *ei = v->getExpInitializer();
@@ -4521 +4521 @@
-
-    v = s->isVarDeclaration();
-Const
+SameAsInitializer
-    {   ExpInitializer *ei = v->getExpInitializer();
-
@@ -4933 +4933 @@
-    s = s->toAlias();
-    v = s->isVarDeclaration();
-Const
+SameAsInitializer
-    {   ExpInitializer *ei = v->getExpInitializer();
-

dmd/optimize.c

@@ -195 +195 @@
-
-    //printf("AddrExp::optimize(result = %d) %s\n", result, toChars());
-
+
+
+
-    // Convert &*ex to ex
-    if (e1->op == TOKstar)