Always use packed structs. This isn't really very nice, but there's

nothing fundamentally wrong with it. Emitting unpacked structs where
possible is more work for almost no practical benefit.  We'll probably
want to fix it at some point anyway, but it's low priority.

The issue with long double in particular is that LLVM thinks an X86 long
double is 10 bytes, while clang considers it for all purposes to be
either 12 or 16 bytes, depending on the platform, even in a packed
struct.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@51673 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/CodeGen/CodeGenTypes.cpp b/lib/CodeGen/CodeGenTypes.cpp
index 5efde77a7d220b7f150188d0f5529834ea40c8ca..ec4f6df2b4db069cf7b0df37dffe937989f0a128 100644 (file)
--- a/lib/CodeGen/CodeGenTypes.cpp
+++ b/lib/CodeGen/CodeGenTypes.cpp
@@ -482,14 +482,13 @@ void RecordOrganizer::layoutStructFields(const ASTRecordLayout &RL) {
   // FIXME : Use SmallVector
   uint64_t llvmSize = 0;
   std::vector<const llvm::Type*> LLVMFields;
-  bool packedStruct = false;
   int NumMembers = RD.getNumMembers();
 
   for (int curField = 0; curField < NumMembers; curField++) {
     const FieldDecl *FD = RD.getMember(curField);
     uint64_t offset = RL.getFieldOffset(curField);
     const llvm::Type *Ty = CGT.ConvertTypeRecursive(FD->getType());
-    uint64_t size = CGT.getTargetData().getABITypeSize(Ty) * 8;
+    uint64_t size = CGT.getTargetData().getTypeStoreSizeInBits(Ty);
 
     if (FD->isBitField()) {
       Expr *BitWidth = FD->getBitWidth();
@@ -513,12 +512,6 @@ void RecordOrganizer::layoutStructFields(const ASTRecordLayout &RL) {
         llvmSize += 8;
       }
 
-      unsigned Align = CGT.getTargetData().getABITypeAlignment(Ty) * 8;
-      if (llvmSize % Align)
-        packedStruct = true;
-      else if (offset == 0 && RL.getAlignment() % Align)
-        packedStruct = true;
-
       llvmSize += size;
       CGT.addFieldInfo(FD, LLVMFields.size());
       LLVMFields.push_back(Ty);
@@ -530,7 +523,7 @@ void RecordOrganizer::layoutStructFields(const ASTRecordLayout &RL) {
     llvmSize += 8;
   }
 
-  STy = llvm::StructType::get(LLVMFields, packedStruct);
+  STy = llvm::StructType::get(LLVMFields, true);
   assert(CGT.getTargetData().getABITypeSizeInBits(STy) == RL.getSize());
 }
 

diff --git a/test/CodeGen/struct-x86-darwin.c b/test/CodeGen/struct-x86-darwin.c
index 3d3729dc9b9c24dc7a4ed40ea9b924027cc8ff51..68e6d72961824b0df23a3cb21ed2304766d76b20 100644 (file)
--- a/test/CodeGen/struct-x86-darwin.c
+++ b/test/CodeGen/struct-x86-darwin.c
@@ -1,16 +1,14 @@
-// RUN: clang < %s -emit-llvm > %t1
-// Run  grep "STest1 = type { i32, \[4 x i16\], double }" %t1 &&
-// RUN: grep "STest2 = type { i16, i16, i32, i32 }" %t1 &&
-// RUN: grep "STest3 = type { i8, i8, i16, i32 }" %t1 &&
-// RUN: grep "STestB1 = type { i8, i8 }" %t1 &&
-// RUN: grep "STestB2 = type { i8, i8, i8 }" %t1 &&
-// RUN: grep "STestB3 = type { i8, i8 }" %t1 &&
-// RUN: grep "STestB4 = type { i8, i8, i8, i8 }" %t1
-// RUN: grep "STestB5 = type { i8, i8, i8, i8, i8, i8 }" %t1
-// RUN: grep "STestB6 = type { i8, i8, i8, i8 }" %t1
+// RUN: clang < %s -emit-llvm > %t1 -triple=i686-apple-darwin9
+// Run  grep "STest1 = type <{ i32, \[4 x i16\], double }>" %t1 &&
+// RUN: grep "STest2 = type <{ i16, i16, i32, i32 }>" %t1 &&
+// RUN: grep "STest3 = type <{ i8, i8, i16, i32 }>" %t1 &&
+// RUN: grep "STestB1 = type <{ i8, i8 }>" %t1 &&
+// RUN: grep "STestB2 = type <{ i8, i8, i8 }>" %t1 &&
+// RUN: grep "STestB3 = type <{ i8, i8 }>" %t1 &&
+// RUN: grep "STestB4 = type <{ i8, i8, i8, i8 }>" %t1
+// RUN: grep "STestB5 = type <{ i8, i8, i8, i8, i8, i8 }>" %t1
+// RUN: grep "STestB6 = type <{ i8, i8, i8, i8 }>" %t1
 // Test struct layout for x86-darwin target
-// FIXME : Enable this test for x86-darwin only. At the moment clang hard codes
-// x86-darwin as the target
 
 struct STest1 {int x; short y[4]; double z; } st1;
 struct STest2 {short a,b; int c,d; } st2;

diff --git a/test/CodeGen/struct.c b/test/CodeGen/struct.c
index f17a7af76c8358da30ca9a139c1d39b59426af43..f567a0b2ff16959c6f1fd384e5690da23f19eeba 100644 (file)
--- a/test/CodeGen/struct.c
+++ b/test/CodeGen/struct.c
@@ -163,3 +163,6 @@ int f14(int i, ...) {
 
 /* Attribute packed */
 struct __attribute__((packed)) S2839 { double a[19];  signed char b; } s2839[5];
+
+struct __attribute__((packed)) SS { long double a; char b; } SS;
+