objective-c blocks: Consider padding due to alignment
after the fixed size block header when generating
captured block variable info. // rdar://12773256
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@169285 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/CGBlocks.cpp b/lib/CodeGen/CGBlocks.cpp
index 1d8b326..d181da2 100644
--- a/lib/CodeGen/CGBlocks.cpp
+++ b/lib/CodeGen/CGBlocks.cpp
@@ -428,7 +428,11 @@
// to get reproducible results. There should probably be an
// llvm::array_pod_stable_sort.
std::stable_sort(layout.begin(), layout.end());
-
+
+ // Needed for blocks layout info.
+ info.BlockHeaderForcedGapOffset = info.BlockSize;
+ info.BlockHeaderForcedGapSize = CharUnits::Zero();
+
CharUnits &blockSize = info.BlockSize;
info.BlockAlign = std::max(maxFieldAlign, info.BlockAlign);
@@ -469,17 +473,22 @@
endAlign = getLowBit(blockSize);
// ...until we get to the alignment of the maximum field.
- if (endAlign >= maxFieldAlign)
+ if (endAlign >= maxFieldAlign) {
+ if (li == first) {
+ // No user field was appended. So, a gap was added.
+ // Save total gap size for use in block layout bit map.
+ info.BlockHeaderForcedGapSize = li->Size;
+ }
break;
+ }
}
-
// Don't re-append everything we just appended.
layout.erase(first, li);
}
}
assert(endAlign == getLowBit(blockSize));
-
+
// At this point, we just have to add padding if the end align still
// isn't aligned right.
if (endAlign < maxFieldAlign) {
@@ -494,7 +503,6 @@
assert(endAlign >= maxFieldAlign);
assert(endAlign == getLowBit(blockSize));
-
// Slam everything else on now. This works because they have
// strictly decreasing alignment and we expect that size is always a
// multiple of alignment.
diff --git a/lib/CodeGen/CGBlocks.h b/lib/CodeGen/CGBlocks.h
index e63d4b6..0e40478 100644
--- a/lib/CodeGen/CGBlocks.h
+++ b/lib/CodeGen/CGBlocks.h
@@ -211,6 +211,14 @@
const BlockExpr *BlockExpression;
CharUnits BlockSize;
CharUnits BlockAlign;
+
+ // Offset of the gap caused by block header having a smaller
+ // alignment than the alignment of the block descriptor. This
+ // is the gap offset before the first capturued field.
+ CharUnits BlockHeaderForcedGapOffset;
+ // Gap size caused by aligning first field after block header.
+ // This could be zero if no forced alignment is required.
+ CharUnits BlockHeaderForcedGapSize;
/// An instruction which dominates the full-expression that the
/// block is inside.
diff --git a/lib/CodeGen/CGObjCMac.cpp b/lib/CodeGen/CGObjCMac.cpp
index f4b42bb..d84875b 100644
--- a/lib/CodeGen/CGObjCMac.cpp
+++ b/lib/CodeGen/CGObjCMac.cpp
@@ -2424,7 +2424,10 @@
// Ignore the optional 'this' capture: C++ objects are not assumed
// to be GC'ed.
-
+ if (blockInfo.BlockHeaderForcedGapSize != CharUnits::Zero())
+ UpdateRunSkipBlockVars(false, Qualifiers::OCL_None,
+ blockInfo.BlockHeaderForcedGapOffset,
+ blockInfo.BlockHeaderForcedGapSize);
// Walk the captured variables.
for (BlockDecl::capture_const_iterator ci = blockDecl->capture_begin(),
ce = blockDecl->capture_end(); ci != ce; ++ci) {