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Sema: Fix a subtle i64 -> i32 truncation which broke layout of large structures 

with bit-fields.

llvm-svn: 107185
This commit is contained in:
Daniel Dunbar 2010-06-29 18:34:35 +00:00
parent a4575f5b31
commit f35e76552f
2 changed files with 11 additions and 1 deletions
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2
clang/lib/AST/RecordLayoutBuilder.cpp
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@ -1296,7 +1296,7 @@ void RecordLayoutBuilder::LayoutBitField(const FieldDecl *D) {
// Check if we need to add padding to give the field the correct alignment.
if (FieldSize == 0 || (FieldOffset & (FieldAlign-1)) + FieldSize > TypeSize)
FieldOffset = (FieldOffset + (FieldAlign-1)) & ~(FieldAlign-1);
FieldOffset = llvm::RoundUpToAlignment(FieldOffset, FieldAlign);
// Padding members don't affect overall alignment.
if (!D->getIdentifier())

10
clang/test/Sema/bitfield-layout.c
View File

@ -30,3 +30,13 @@ CHECK_ALIGN(struct, e, 1)
struct f {__attribute((aligned(8))) int x : 30, y : 30, z : 30;};
CHECK_SIZE(struct, f, 24)
CHECK_ALIGN(struct, f, 8)
// Large structure (overflows i32, in bits).
struct s0 {
char a[0x32100000];
int x:30, y:30;
};
CHECK_SIZE(struct, s0, 0x32100008)
CHECK_ALIGN(struct, s0, 4)