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[Issue 3174] New: (ICE): Compiler crash or compiler error with auto returns and const / immutable / invarient / pure
Jul 14, 2009
sandford@jhu.edu
[Issue 3174] ICE(mtype.c): Compiler crash or compiler error with auto returns and const / immutable / invarient / pure
Oct 02, 2009
Don
Oct 13, 2009
Walter Bright
July 14, 2009
Gravatar of sandford@jhu.eduPosted by sandford@jhu.eduReply
sandford@jhu.edu
Gravatar of sandford@jhu.edu


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http://d.puremagic.com/issues/show_bug.cgi?id=3174

           Summary: (ICE): Compiler crash or compiler error with auto
                    returns and const / immutable / invarient / pure
           Product: D
           Version: 2.031
          Platform: x86
        OS/Version: Windows
            Status: NEW
          Keywords: ice-on-valid-code, rejects-valid
          Severity: normal
          Priority: P2
         Component: DMD
        AssignedTo: nobody@puremagic.com
        ReportedBy: sandford@jhu.edu


DMD either crashes or fails to compile a auto return function marked const/immutable or invarient

class A {
    const      foo(int i)  { return i; } // DMD crash
    const auto foo(int i)  { return i; } // DMD crash
    pure  auto foo(int i)  { return i; } // Okay
    auto foo(int i) pure  { return i; }  // Fails to compile
         foo(int i) const { return i; }  // Fails to compile
    auto foo(int i) const { return i; }  // Fails to compile
}
void main(char[][] args) {
    const A a = new A();
    a.foo(5);
    return;
}

Errors for auto foo(int i) const { return i; } (line 146)
main.d(147): found 'int' when expecting ')'
main.d(147): no identifier for declarator foo
main.d(147): semicolon expected, not 'i'
main.d(147): no identifier for declarator i
main.d(147): semicolon expected, not ')'
main.d(147): Declaration expected, not ')'
main.d(148): unrecognized declaration

The issues using const also apply to immutable / invarient.

DMD Crash:
Unhandled exception at 0x00410ba3 in dmd.exe: 0xC0000005: Access violation
reading location 0x00000000.
inside mytype.c, at line 3800:

void TypeFunction::toDecoBuffer(OutBuffer *buf, int flag)
{   unsigned char mc;

    //printf("TypeFunction::toDecoBuffer() this = %p %s\n", this, toChars());
    //static int nest; if (++nest == 50) *(char*)0=0;
    if (inuse)
    {    inuse = 2;        // flag error to caller
    return;
    }
    inuse++;
#if 1
    if (mod & MODshared)
    buf->writeByte('O');
    if (mod & MODconst)
    buf->writeByte('x');
    else if (mod & MODinvariant)
    buf->writeByte('y');
#endif
    switch (linkage)
    {
    case LINKd:        mc = 'F';    break;
    case LINKc:        mc = 'U';    break;
    case LINKwindows:    mc = 'W';    break;
    case LINKpascal:    mc = 'V';    break;
    case LINKcpp:        mc = 'R';    break;
    default:
        assert(0);
    }
    buf->writeByte(mc);
    if (ispure || isnothrow || isref)
    {
    if (ispure)
        buf->writestring("Na");
    if (isnothrow)
        buf->writestring("Nb");
    if (isref)
        buf->writestring("Nc");
    }
    // Write argument types
    Argument::argsToDecoBuffer(buf, parameters);
    //if (buf->data[buf->offset - 1] == '@') halt();
    buf->writeByte('Z' - varargs);    // mark end of arg list
    next->toDecoBuffer(buf);



Watch reports
next is null
this    0x076471c4
TypeFunction::toDecoBuffer::buf    0x0012faa4
TypeFunction::toDecoBuffer::mc    70 'F'
TypeFunction::toDecoBuffer::flag    0

Call Stack:
>	dmd.exe!TypeFunction::toDecoBuffer(OutBuffer*,int )()  Line 3800 + 0x8 bytes	C++
     dmd.exe!Type::merge()()  Line 1122    C++
     dmd.exe!FuncDeclaration::semantic(Scope*)()  Line 165 + 0x7 bytes    C++
     dmd.exe!ClassDeclaration::semantic(Scope*)()  Line 596    C++
     dmd.exe!Module::semantic()()  Line 675    C++
     dmd.exe!main()  Line 1057    C++
     dmd.exe!_mainCRTStartup()  + 0xa9 bytes
     kernel32.dll!7c816fe7()

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October 02, 2009
Gravatar of DonPosted by Don
in reply to sandford@jhu.edu		Reply
Don
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Posted in reply to sandford@jhu.edu


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http://d.puremagic.com/issues/show_bug.cgi?id=3174


Don <clugdbug@yahoo.com.au> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |patch


--- Comment #1 from Don <clugdbug@yahoo.com.au> 2009-10-02 00:08:13 PDT ---
There are actually 2 independent bugs here. My patch only deals with the ICE. I've created bug 3359 for the parsing failure.

CAUSE: It's trying to do type->deco->merge() on a function, when it doesn't yet know the return type. merge() is never done on plain auto functions, which is why the thrid case doesn't segfault.

COMMENT: mtype.c, TypeFunction::toDecoBuffer() desperately needs an
assert(next); to generate an ICE instead of a segfault. I have seen at least
five different
bugs that crash there.

PATCH: I've done this by copy-and-paste, you probably want to reorganize this
function a bit to avoid duplication. This makes 'const' functions behave the
same as 'auto'
-- but actually plain 'auto'  functions suffer from the other bugs, I think
because the merge() never happens.

Index: func.c ===================================================================
--- func.c    (revision 75)
+++ func.c    (working copy)
@@ -144,6 +144,13 @@
      * to the function type
      */
     type = type->semantic(loc, sc);
+        if (type->ty != Tfunction)
+    {
+        error("%s must be a function", toChars());
+        return;
+    }
+        f = (TypeFunction *)(type);
+
     unsigned stc = storage_class;
     if (type->isInvariant())
         stc |= STCimmutable;
@@ -159,22 +166,22 @@
         case STCimmutable | STCshared:
         // Don't use toInvariant(), as that will do a merge()
         type = type->makeInvariant();
-        type->deco = type->merge()->deco;
+        if (f->next) type->deco = type->merge()->deco;
         break;

         case STCconst:
         type = type->makeConst();
-        type->deco = type->merge()->deco;
+        if (f->next) type->deco = type->merge()->deco;
         break;

         case STCshared | STCconst:
         type = type->makeSharedConst();
-        type->deco = type->merge()->deco;
+        if (f->next) type->deco = type->merge()->deco;
         break;

         case STCshared:
         type = type->makeShared();
-        type->deco = type->merge()->deco;
+        if (f->next) type->deco = type->merge()->deco;
         break;

         case 0:

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October 13, 2009
Gravatar of Walter BrightPosted by Walter Bright
in reply to sandford@jhu.edu		Reply
Walter Bright
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Posted in reply to sandford@jhu.edu


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http://d.puremagic.com/issues/show_bug.cgi?id=3174


Walter Bright <bugzilla@digitalmars.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
                 CC|                            |bugzilla@digitalmars.com
         Resolution|                            |FIXED


--- Comment #2 from Walter Bright <bugzilla@digitalmars.com> 2009-10-13 13:46:05 PDT ---
Fixed dmd 1.049 and 2.034

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