r261260 - [Sema] Fix bug in TypeLocBuilder::pushImpl
Akira Hatanaka via cfe-commits
cfe-commits at lists.llvm.org
Thu Feb 18 13:05:09 PST 2016
Author: ahatanak
Date: Thu Feb 18 15:05:09 2016
New Revision: 261260
URL: http://llvm.org/viewvc/llvm-project?rev=261260&view=rev
Log:
[Sema] Fix bug in TypeLocBuilder::pushImpl
The code in TypeLocBuilder::pushImpl wasn't correctly handling the case
where an element that has an 8-byte alignment was being pushed.
I plan to follow up with a patch to remove redundancies and simplify the
function.
rdar://problem/23838912
Differential Revision: http://reviews.llvm.org/D16843
Added:
cfe/trunk/test/SemaObjCXX/typeloc-data-alignment.mm
Modified:
cfe/trunk/lib/Sema/TypeLocBuilder.cpp
Modified: cfe/trunk/lib/Sema/TypeLocBuilder.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/TypeLocBuilder.cpp?rev=261260&r1=261259&r2=261260&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/TypeLocBuilder.cpp (original)
+++ cfe/trunk/lib/Sema/TypeLocBuilder.cpp Thu Feb 18 15:05:09 2016
@@ -115,11 +115,39 @@ TypeLoc TypeLocBuilder::pushImpl(QualTyp
NumBytesAtAlign4 += LocalSize;
}
} else if (LocalAlignment == 8) {
- if (!NumBytesAtAlign8 && NumBytesAtAlign4 % 8 != 0) {
- // No existing padding and misaligned members; add in 4 bytes padding
- memmove(&Buffer[Index - 4], &Buffer[Index], NumBytesAtAlign4);
- Index -= 4;
+ if (NumBytesAtAlign8 == 0) {
+ // We have not seen any 8-byte aligned element yet. We insert a padding
+ // only if the new Index is not 8-byte-aligned.
+ if ((Index - LocalSize) % 8 != 0) {
+ memmove(&Buffer[Index - 4], &Buffer[Index], NumBytesAtAlign4);
+ Index -= 4;
+ }
+ } else {
+ unsigned Padding = NumBytesAtAlign4 % 8;
+ if (Padding == 0) {
+ if (LocalSize % 8 == 0) {
+ // Everything is set: there's no padding and we don't need to add
+ // any.
+ } else {
+ assert(LocalSize % 8 == 4);
+ // No existing padding; add in 4 bytes padding
+ memmove(&Buffer[Index - 4], &Buffer[Index], NumBytesAtAlign4);
+ Index -= 4;
+ }
+ } else {
+ assert(Padding == 4);
+ if (LocalSize % 8 == 0) {
+ // Everything is set: there's 4 bytes padding and we don't need
+ // to add any.
+ } else {
+ assert(LocalSize % 8 == 4);
+ // There are 4 bytes padding, but we don't need any; remove it.
+ memmove(&Buffer[Index + 4], &Buffer[Index], NumBytesAtAlign4);
+ Index += 4;
+ }
+ }
}
+
// Forget about any padding.
NumBytesAtAlign4 = 0;
NumBytesAtAlign8 += LocalSize;
Added: cfe/trunk/test/SemaObjCXX/typeloc-data-alignment.mm
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/SemaObjCXX/typeloc-data-alignment.mm?rev=261260&view=auto
==============================================================================
--- cfe/trunk/test/SemaObjCXX/typeloc-data-alignment.mm (added)
+++ cfe/trunk/test/SemaObjCXX/typeloc-data-alignment.mm Thu Feb 18 15:05:09 2016
@@ -0,0 +1,12 @@
+// RUN: %clang_cc1 -fsyntax-only -verify %s
+// expected-no-diagnostics
+
+// Make sure this doesn't crash.
+
+ at protocol P
+ at end
+template <class T>
+id<P> foo(T) {
+ int i;
+ foo(i);
+}
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