improve support for big endian targets, fixing PR8171, patch
by Heikki Kultala!
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@125784 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/CGExprConstant.cpp b/lib/CodeGen/CGExprConstant.cpp
index 1f222a2..40d7b6c 100644
--- a/lib/CodeGen/CGExprConstant.cpp
+++ b/lib/CodeGen/CGExprConstant.cpp
@@ -231,7 +231,7 @@
if (CGM.getTargetData().isBigEndian()) {
// We want the high bits.
- Tmp = FieldValue.lshr(Tmp.getBitWidth() - 8).trunc(8);
+ Tmp = FieldValue.lshr(FieldValue.getBitWidth() - 8).trunc(8);
} else {
// We want the low bits.
Tmp = FieldValue.trunc(8);
diff --git a/lib/CodeGen/CGRecordLayoutBuilder.cpp b/lib/CodeGen/CGRecordLayoutBuilder.cpp
index 7704091..4b19aef 100644
--- a/lib/CodeGen/CGRecordLayoutBuilder.cpp
+++ b/lib/CodeGen/CGRecordLayoutBuilder.cpp
@@ -225,6 +225,12 @@
FieldSize = TypeSizeInBits;
}
+ // in big-endian machines the first fields are in higher bit positions,
+ // so revert the offset. The byte offsets are reversed(back) later.
+ if (Types.getTargetData().isBigEndian()) {
+ FieldOffset = ((ContainingTypeSizeInBits)-FieldOffset-FieldSize);
+ }
+
// Compute the access components. The policy we use is to start by attempting
// to access using the width of the bit-field type itself and to always access
// at aligned indices of that type. If such an access would fail because it
@@ -232,7 +238,6 @@
// power of two and retry. The current algorithm assumes pow2 sized types,
// although this is easy to fix.
//
- // FIXME: This algorithm is wrong on big-endian systems, I think.
assert(llvm::isPowerOf2_32(TypeSizeInBits) && "Unexpected type size!");
CGBitFieldInfo::AccessInfo Components[3];
unsigned NumComponents = 0;
@@ -280,7 +285,15 @@
// FIXME: We still follow the old access pattern of only using the field
// byte offset. We should switch this once we fix the struct layout to be
// pretty.
- AI.FieldByteOffset = AccessStart / 8;
+
+ // on big-endian machines we reverted the bit offset because first fields are
+ // in higher bits. But this also reverts the bytes, so fix this here by reverting
+ // the byte offset on big-endian machines.
+ if (Types.getTargetData().isBigEndian()) {
+ AI.FieldByteOffset = (ContainingTypeSizeInBits - AccessStart - AccessWidth )/8;
+ } else {
+ AI.FieldByteOffset = AccessStart / 8;
+ }
AI.FieldBitStart = AccessBitsInFieldStart - AccessStart;
AI.AccessWidth = AccessWidth;
AI.AccessAlignment = llvm::MinAlign(ContainingTypeAlign, AccessStart) / 8;