From cb77930d6b20e53c735233eecf4572a1c30eb0c0 Mon Sep 17 00:00:00 2001
From: Yunzhong Gao <Yunzhong_Gao@playstation.sony.com>
Date: Wed, 10 Jun 2015 00:27:52 +0000
Subject: Implementing C99 partial re-initialization behavior (DR-253)

Based on previous discussion on the mailing list, clang currently lacks support
for C99 partial re-initialization behavior:
Reference: http://lists.cs.uiuc.edu/pipermail/cfe-dev/2013-April/029188.html
Reference: http://www.open-std.org/jtc1/sc22/wg14/www/docs/dr_253.htm

This patch attempts to fix this problem.

Given the following code snippet,

struct P1 { char x[6]; };
struct LP1 { struct P1 p1; };

struct LP1 l = { .p1 = { "foo" }, .p1.x[2] = 'x' };
// this example is adapted from the example for "struct fred x[]" in DR-253;
// currently clang produces in l: { "\0\0x" },
//   whereas gcc 4.8 produces { "fox" };
// with this fix, clang will also produce: { "fox" };


Differential Review: http://reviews.llvm.org/D5789

llvm-svn: 239446
---
 clang/lib/Serialization/ASTReaderStmt.cpp | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

(limited to 'clang/lib/Serialization/ASTReaderStmt.cpp')

diff --git a/clang/lib/Serialization/ASTReaderStmt.cpp b/clang/lib/Serialization/ASTReaderStmt.cpp
index d1ecd467248..d84b5be5850 100644
--- a/clang/lib/Serialization/ASTReaderStmt.cpp
+++ b/clang/lib/Serialization/ASTReaderStmt.cpp
@@ -801,6 +801,16 @@ void ASTStmtReader::VisitDesignatedInitExpr(DesignatedInitExpr *E) {
                     Designators.data(), Designators.size());
 }
 
+void ASTStmtReader::VisitDesignatedInitUpdateExpr(DesignatedInitUpdateExpr *E) {
+  VisitExpr(E);
+  E->setBase(Reader.ReadSubExpr());
+  E->setUpdater(Reader.ReadSubExpr());
+}
+
+void ASTStmtReader::VisitNoInitExpr(NoInitExpr *E) {
+  VisitExpr(E);
+}
+
 void ASTStmtReader::VisitImplicitValueInitExpr(ImplicitValueInitExpr *E) {
   VisitExpr(E);
 }
@@ -2549,10 +2559,18 @@ Stmt *ASTReader::ReadStmtFromStream(ModuleFile &F) {
 
       break;
 
+    case EXPR_DESIGNATED_INIT_UPDATE:
+      S = new (Context) DesignatedInitUpdateExpr(Empty);
+      break;
+
     case EXPR_IMPLICIT_VALUE_INIT:
       S = new (Context) ImplicitValueInitExpr(Empty);
       break;
 
+    case EXPR_NO_INIT:
+      S = new (Context) NoInitExpr(Empty);
+      break;
+
     case EXPR_VA_ARG:
       S = new (Context) VAArgExpr(Empty);
       break;
-- 
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