[Sema] Fix PR38987: keep end location of a direct initializer list

[orivej]

Summary

If PerformConstructorInitialization of a direct initializer list constructor is called while instantiating a template, it has brace locations in its BraceLoc arguments but not in the Kind argument.

This reverts the hunk https://reviews.llvm.org/D41921#inline-468844.

[vsk]

Thanks for looking into this! Do you know why the InitializationKind doesn't contain the right brace locations in this scenario? Should it?

[orivej]

I don't have the complete picture yet. (This is why the summary is so short.)
I have looked up that IK_DirectList Kind was known not to carry a valid ParenRange since https://github.com/llvm-mirror/clang/commit/188158db29f50443b6e412f2a40c800b2669c957, and that PerformConstructorInitialization acquired BraceLoc arguments specifically to support CXXTemporaryObjectExpr: https://github.com/llvm-mirror/clang/commit/1245a54ca6e9c5b14196461dc3f84b24ea6594b1#diff-d7cc8293491a9fdddee7ba857c028256R5921 , but then it appears that CXXTemporaryObjectExpr Kind has acquired a valid ParenRange, except when it is instantiated from a template…

[orivej]

D41921 was the last big change necessary to fix clang crashes on code coverage, but without the fixup in this review clang crashes on about 1.5 times more projects that I maintain than before. It seems useful to include this in the 7.0.1 release. (After the fixup the only crasher is scipy, being dealt with in D53244.)

[vsk]

The history seems complicated. I think it'd be really useful to sort out why getParenOrBraceRange() couldn't give the right result, but I'd be happy to see this land first to address the crash.

lib/Sema/SemaInit.cpp

PerformConstructorInitialization(Sema &S,
   if (isExplicitTemporary(Entity, Kind, NumArgs)) {
     // An explicitly-constructed temporary, e.g., X(1, 2).
     if (S.DiagnoseUseOfDecl(Constructor, Loc))
       return ExprError();
 
     TypeSourceInfo *TSInfo = Entity.getTypeSourceInfo();
     if (!TSInfo)
       TSInfo = S.Context.getTrivialTypeSourceInfo(Entity.getType(), Loc);
-    SourceRange ParenOrBraceRange = Kind.getParenOrBraceRange();
+    SourceRange ParenOrBraceRange =
+        (Kind.getKind() == InitializationKind::IK_DirectList)
+        ? SourceRange(LBraceLoc, RBraceLoc)
+        : Kind.getParenOrBraceRange();
 
     if (auto *Shadow = dyn_cast<ConstructorUsingShadowDecl>(
             Step.Function.FoundDecl.getDecl())) {
       Constructor = S.findInheritingConstructor(Loc, Constructor, Shadow);
       if (S.DiagnoseUseOfDecl(Constructor, Loc))
         return ExprError();
     }
     S.MarkFunctionReferenced(Loc, Constructor);

test/SemaCXX/sourceranges.cpp

 void construct() {
   using namespace foo;
   A a = A(12);
   // CHECK: CXXConstructExpr {{0x[0-9a-fA-F]+}} <col:9, col:13> 'foo::A' 'void (int){{( __attribute__\(\(thiscall\)\))?}}'
   D d = D(12);
   // CHECK: CXXConstructExpr {{0x[0-9a-fA-F]+}} <col:9, col:13> 'D' 'void (int){{( __attribute__\(\(thiscall\)\))?}}'
 }
 
+namespace PR38987 {
+struct A { A(); };
+template <class T> void f() { T{}; }
+template void f<A>();
+// CHECK: CXXTemporaryObjectExpr {{.*}} <col:31, col:33> 'PR38987::A':'PR38987::A'
+}
+
 void abort() __attribute__((noreturn));
 
 namespace std {
 typedef decltype(sizeof(int)) size_t;
 
 template <typename E> struct initializer_list {
   const E *p;
   size_t n;