implement DIP1008 - Exceptions and @nogc

Author: WalterBright

src/ddmd/backend/rtlsym.c

@@ -60,11 +60,11 @@ void rtlsym_init()
 
         //printf("rtlsym_init(%s)\n", regm_str(FREGSAVED));
 
-#if MARS
         type *t = type_fake(TYnfunc);
         t->Tmangle = mTYman_c;
         t->Tcount++;
 
+#if MARS
         // Variadic function
         type *tv = type_fake(TYnfunc);
         tv->Tmangle = mTYman_c;

src/ddmd/backend/rtlsym.d

@@ -58,6 +58,7 @@ enum
     RTLSYM_DSWITCHERR,
     RTLSYM_DHIDDENFUNC,
     RTLSYM_NEWCLASS,
+    RTLSYM_NEWTHROW,
     RTLSYM_NEWARRAYT,
     RTLSYM_NEWARRAYIT,
     RTLSYM_NEWITEMT,

src/ddmd/backend/rtlsym.h

@@ -83,6 +83,7 @@ SYMBOL_MARS(SWITCH_DSTRING,FLfunc,FREGSAVED,"_d_switch_dstring", 0, t) \
 SYMBOL_MARS(DSWITCHERR,    FLfunc,FREGSAVED,"_d_switch_error", SFLexit, t) \
 SYMBOL_MARS(DHIDDENFUNC,   FLfunc,FREGSAVED,"_d_hidden_func", 0, t) \
 SYMBOL_MARS(NEWCLASS,      FLfunc,FREGSAVED,"_d_newclass", 0, t) \
+SYMBOL_MARS(NEWTHROW,      FLfunc,FREGSAVED,"_d_newThrowable", 0, t) \
 SYMBOL_MARS(NEWARRAYT,     FLfunc,FREGSAVED,"_d_newarrayT", 0, t) \
 SYMBOL_MARS(NEWARRAYIT,    FLfunc,FREGSAVED,"_d_newarrayiT", 0, t) \
 SYMBOL_MARS(NEWITEMT,     FLfunc,FREGSAVED,"_d_newitemT", 0, t) \

src/ddmd/declaration.d

@@ -1019,9 +1019,10 @@ extern (C++) class VarDeclaration : Declaration
     uint sequenceNumber;            // order the variables are declared
     __gshared uint nextSequenceNumber;   // the counter for sequenceNumber
     FuncDeclarations nestedrefs;    // referenced by these lexically nested functions
-    bool isargptr;                  // if parameter that _argptr points to
     structalign_t alignment;
+    bool isargptr;                  // if parameter that _argptr points to
     bool ctorinit;                  // it has been initialized in a ctor
+    bool iscatchvar;                // this is the exception object variable in catch() clause
 
     // Both these mean the var is not rebindable once assigned,
     // and the destructor gets run when it goes out of scope
@@ -2170,6 +2171,9 @@ extern (C++) class VarDeclaration : Declaration
             return null;
         }
 
+        if (iscatchvar)
+            return null;    // destructor is built by `void semantic(Catch c, Scope* sc)`, not here
+
         Expression e = null;
         // Destructors for structs and arrays of structs
         Type tv = type.baseElemOf();

src/ddmd/declaration.h

@@ -238,9 +238,10 @@ class VarDeclaration : public Declaration
     unsigned offset;
     unsigned sequenceNumber;     // order the variables are declared
     FuncDeclarations nestedrefs; // referenced by these lexically nested functions
-    bool isargptr;              // if parameter that _argptr points to
     structalign_t alignment;
+    bool isargptr;              // if parameter that _argptr points to
     bool ctorinit;              // it has been initialized in a ctor
+    bool iscatchvar;            // this is the exception object variable in catch() clause
     bool onstack;               // it is a class that was allocated on the stack
     bool mynew;                 // it is a class new'd with custom operator new
     int canassign;              // it can be assigned to

src/ddmd/escape.d

@@ -430,7 +430,8 @@ bool checkThrowEscape(Scope* sc, Expression e, bool gag)
 
         Dsymbol p = v.toParent2();
 
-        if (v.isScope())
+        if (v.isScope() && !v.iscatchvar)       // special case: allow catch var to be rethrown
+                                                // despite being `scope`
         {
             if (sc._module && sc._module.isRoot())
             {

src/ddmd/expression.d

@@ -5947,10 +5947,12 @@ extern (C++) final class NewExp : Expression
     Expressions* newargs;       // Array of Expression's to call new operator
     Type newtype;
     Expressions* arguments;     // Array of Expression's
+
     Expression argprefix;       // expression to be evaluated just before arguments[]
     CtorDeclaration member;     // constructor function
     NewDeclaration allocator;   // allocator function
-    int onstack;                // allocate on stack
+    bool onstack;               // allocate on stack
+    bool thrownew;              // this NewExp is the expression of a ThrowStatement
 
     extern (D) this(Loc loc, Expression thisexp, Expressions* newargs, Type newtype, Expressions* arguments)
     {

src/ddmd/expression.h

@@ -1,6 +1,6 @@
 
 /* Compiler implementation of the D programming language
- * Copyright (c) 1999-2016 by Digital Mars
+ * Copyright (c) 1999-2017 by Digital Mars
  * All Rights Reserved
  * written by Walter Bright
  * http://www.digitalmars.com
@@ -527,7 +527,8 @@ class NewExp : public Expression
 
     CtorDeclaration *member;    // constructor function
     NewDeclaration *allocator;  // allocator function
-    int onstack;                // allocate on stack
+    bool onstack;               // allocate on stack
+    bool thrownew;              // this NewExp is the expression of a ThrowStatement
 
     Expression *syntaxCopy();
     Expression *semantic(Scope *sc);

src/ddmd/globals.d

@@ -126,6 +126,7 @@ struct Param
     bool check10378;        // check for issues transitioning to 10738
     bool bug10378;          // use pre- https://issues.dlang.org/show_bug.cgi?id=10378 search strategy
     bool vsafe;             // use enhanced @safe checking
+    bool ehnogc;            // use @nogc exception handling
     /** The --transition=safe switch should only be used to show code with
      * silent semantics changes related to @safe improvements.  It should not be
      * used to hide a feature that will have to go through deprecate-then-error

src/ddmd/globals.h

@@ -115,6 +115,7 @@ struct Param
     bool check10378;    // check for issues transitioning to 10738
     bool bug10378;      // use pre-bugzilla 10378 search strategy
     bool vsafe;         // use enhanced @safe checking
+    bool ehnogc;        // use @nogc exception handling
     bool showGaggedErrors;  // print gagged errors anyway
 
     CPU cpu;                // CPU instruction set to target