Missing info in AST for CXXConstructExpr

[Abramo Bagnara]

Il 28/01/2015 23:07, Richard Smith ha scritto:
> Fixed in r227377.

I'm not sure it is related to your commit, but trying to validate your
changes I've discovered a regression between r224592 and r227424.

For the source:

#include <initializer_list>

typedef std::initializer_list<bool> T;
struct A {
  A(T) {}
};

void f() {
  T x;
  A y = {x};
}

in r224592 we used to get with -ast-print for last function:

void f() {
    T x;
    A y = { x };
}

in r227424 we get:


void f() {
    T x;
    A y = { { { x } } };
}

The difference comes from different AST, r224592:

    `-DeclStmt 0x72db9a8 <line:10:3, col:12>
      `-VarDecl 0x72db1d0 <col:3, col:11> col:5 y 'struct A' cinit
        `-CXXConstructExpr 0x72db970 <col:9, col:11> 'struct A' 'void (T)'
          `-CXXConstructExpr 0x72db818 <col:10> 'T':'class
std::initializer_list<_Bool>' 'void (const class
std::initializer_list<_Bool> &) noexcept'
            `-ImplicitCastExpr 0x72db640 <col:10> 'const class
std::initializer_list<_Bool>' lvalue <NoOp>
              `-DeclRefExpr 0x72db228 <col:10> 'T':'class
std::initializer_list<_Bool>' lvalue Var 0x72dacb0 'x' 'T':'class
std::initializer_list<_Bool>'


while r227424:

    `-DeclStmt 0x8c99f08 <line:10:3, col:12>
      `-VarDecl 0x8c996e0 <col:3, col:11> col:5 y 'struct A' cinit
        `-CXXConstructExpr 0x8c99ed0 <col:9, col:11> 'struct A' 'void (T)'
          `-CXXConstructExpr 0x8c99d78 <col:9, col:11> 'T':'class
std::initializer_list<_Bool>' 'void (const class
std::initializer_list<_Bool> &) noexcept'
            `-InitListExpr 0x8c99b68 <col:9, col:11> 'const class
std::initializer_list<_Bool>' lvalue
              `-ImplicitCastExpr 0x8c99b50 <col:10> 'const class
std::initializer_list<_Bool>' lvalue <NoOp>
                `-DeclRefExpr 0x8c99738 <col:10> 'T':'class
std::initializer_list<_Bool>' lvalue Var 0x8c991c0 'x' 'T':'class
std::initializer_list<_Bool>'


What I can see is:
1) a NoOp ImplicitCastExpr apparently needless in both
2) an extra InitListExpr in r227424


> 
> On Wed, Jan 28, 2015 at 2:27 AM, Abramo Bagnara
> <abramo.bagnara at bugseng.com <mailto:abramo.bagnara at bugseng.com>> wrote:
> 
>     Il 27/01/2015 02:50, Richard Smith ha scritto:
> 
>     >
>     > There should be a CXXFunctionalCastExpr (with cast kind CK_NoOp) between
>     > the MaterializeTemporaryExpr and its contained CXXStdInitializerListExpr:
>     >
>     >     `-CallExpr 0x7962cd0 <line:11:3, col:9> 'void'
>     >       |-ImplicitCastExpr 0x7962cb8 <col:3> 'void
>     > (*)(class std::initializer_list<int>)' <FunctionToPointerDecay>
>     >       | `-DeclRefExpr 0x7962c60 <col:3> 'void
>     > (class std::initializer_list<int>)' lvalue [...]
>     >       `-CXXConstructExpr 0x7962d18 <col:6, col:8> [...]
>     >         `-MaterializeTemporaryExpr 0x7962d00 <col:6, col:8>
>     > 'class std::initializer_list<int>' xvalue
>     > *          `-CXXFunctionalCastExpr 0x... <NoOp>
>     > *            `-CXXStdInitializerListExpr 0x7962910 <col:6,
>     > col:8> 'T':'class std::initializer_list<int>'
>     >               `-MaterializeTemporaryExpr 0x79628f8 <col:6, col:8>
>     > 'const int [1]' xvalue
>     >                 `-InitListExpr 0x79628b0 <col:6, col:8> 'const int [1]'
>     >                   `-IntegerLiteral 0x7962848 <col:7> 'int' 0
>     >
>     > This case appears to be missing from Sema::BuildCXXTypeConstructExpr; it
>     > looks like it assumes that initialization will give us either a
>     > CXXConstructExpr or an InitListExpr.
> 
>     Filed as http://llvm.org/bugs/show_bug.cgi?id=22367 with reference to
>     your proposed solution.
> 
> 
>     --
>     Abramo Bagnara
> 
>     BUGSENG srl - http://bugseng.com
>     mailto:abramo.bagnara at bugseng.com <mailto:abramo.bagnara at bugseng.com>
> 
> 


-- 
Abramo Bagnara

BUGSENG srl - http://bugseng.com
mailto:abramo.bagnara at bugseng.com