Thanks! I assume it's now ok to turn padding into undef again? (btw, do you want to review the patch before commit?)
Nuno ----- Original Message ----- From: "Chris Lattner" <[email protected]> To: <[email protected]> Sent: Tuesday, April 13, 2010 7:16 PM Subject: [cfe-commits] r101155 - in /cfe/trunk:lib/CodeGen/CGExprConstant.cpp test/CodeGen/decl.c > Author: lattner > Date: Tue Apr 13 13:16:19 2010 > New Revision: 101155 > > URL: http://llvm.org/viewvc/llvm-project?rev=101155&view=rev > Log: > Rework the ConstStructBuilder code to emit missing initializer > elements with explicit zero values instead of with tail padding. > On an example like this: > > struct foo { int a; int b; }; > > struct foo fooarray[] = { > {1, 2}, > {4}, > }; > > We now lay this out as: > > @fooarray = global [2 x %struct.foo] [%struct.foo { i32 1, i32 2 }, > %struct.foo { i32 4, i32 0 }] > > instead of as: > > @fooarray = global %0 <{ %struct.foo { i32 1, i32 2 }, %1 { i32 4, [4 x > i8] zeroinitializer } }> > > Preserving both the struct type of the second element, but also the array > type of the entire thing. > > > Modified: > cfe/trunk/lib/CodeGen/CGExprConstant.cpp > cfe/trunk/test/CodeGen/decl.c > > Modified: cfe/trunk/lib/CodeGen/CGExprConstant.cpp > URL: > http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/CodeGen/CGExprConstant.cpp?rev=101155&r1=101154&r2=101155&view=diff > ============================================================================== > --- cfe/trunk/lib/CodeGen/CGExprConstant.cpp (original) > +++ cfe/trunk/lib/CodeGen/CGExprConstant.cpp Tue Apr 13 13:16:19 2010 > @@ -50,10 +50,10 @@ > LLVMStructAlignment(1) { } > > bool AppendField(const FieldDecl *Field, uint64_t FieldOffset, > - const Expr *InitExpr); > + llvm::Constant *InitExpr); > > bool AppendBitField(const FieldDecl *Field, uint64_t FieldOffset, > - const Expr *InitExpr); > + llvm::Constant *InitExpr); > > void AppendPadding(uint64_t NumBytes); > > @@ -74,18 +74,18 @@ > }; > > bool ConstStructBuilder:: > -AppendField(const FieldDecl *Field, uint64_t FieldOffset, const Expr > *InitExpr){ > +AppendField(const FieldDecl *Field, uint64_t FieldOffset, > + llvm::Constant *InitCst) { > uint64_t FieldOffsetInBytes = FieldOffset / 8; > > assert(NextFieldOffsetInBytes <= FieldOffsetInBytes > && "Field offset mismatch!"); > > // Emit the field. > - llvm::Constant *C = CGM.EmitConstantExpr(InitExpr, Field->getType(), > CGF); > - if (!C) > + if (!InitCst) > return false; > > - unsigned FieldAlignment = getAlignment(C); > + unsigned FieldAlignment = getAlignment(InitCst); > > // Round up the field offset to the alignment of the field type. > uint64_t AlignedNextFieldOffsetInBytes = > @@ -111,8 +111,9 @@ > } > > // Add the field. > - Elements.push_back(C); > - NextFieldOffsetInBytes = AlignedNextFieldOffsetInBytes + > getSizeInBytes(C); > + Elements.push_back(InitCst); > + NextFieldOffsetInBytes = AlignedNextFieldOffsetInBytes + > + getSizeInBytes(InitCst); > > if (Packed) > assert(LLVMStructAlignment == 1 && "Packed struct not byte-aligned!"); > @@ -124,11 +125,8 @@ > > bool ConstStructBuilder:: > AppendBitField(const FieldDecl *Field, uint64_t FieldOffset, > - const Expr *InitExpr) { > - llvm::ConstantInt *CI = > - cast_or_null<llvm::ConstantInt>(CGM.EmitConstantExpr(InitExpr, > - > Field->getType(), > - CGF)); > + llvm::Constant *InitCst) { > + llvm::ConstantInt *CI = cast_or_null<llvm::ConstantInt>(InitCst); > // FIXME: Can this ever happen? > if (!CI) > return false; > @@ -323,26 +321,34 @@ > unsigned FieldNo = 0; > unsigned ElementNo = 0; > for (RecordDecl::field_iterator Field = RD->field_begin(), > - FieldEnd = RD->field_end(); > - ElementNo < ILE->getNumInits() && Field != FieldEnd; > - ++Field, ++FieldNo) { > + FieldEnd = RD->field_end(); Field != FieldEnd; ++Field, ++FieldNo) > { > + > + // If this is a union, skip all the fields that aren't being > initialized. > if (RD->isUnion() && ILE->getInitializedFieldInUnion() != *Field) > continue; > > - if (Field->isBitField()) { > - if (!Field->getIdentifier()) > - continue; > + // Don't emit anonymous bitfields, they just affect layout. > + if (Field->isBitField() && !Field->getIdentifier()) > + continue; > > - if (!AppendBitField(*Field, Layout.getFieldOffset(FieldNo), > - ILE->getInit(ElementNo))) > + // Get the initializer. A struct can include fields without > initializers, > + // we just use explicit null values for them. > + llvm::Constant *EltInit; > + if (ElementNo < ILE->getNumInits()) > + EltInit = CGM.EmitConstantExpr(ILE->getInit(ElementNo++), > + Field->getType(), CGF); > + else > + EltInit = CGM.EmitNullConstant(Field->getType()); > + > + if (!Field->isBitField()) { > + // Handle non-bitfield members. > + if (!AppendField(*Field, Layout.getFieldOffset(FieldNo), EltInit)) > return false; > } else { > - if (!AppendField(*Field, Layout.getFieldOffset(FieldNo), > - ILE->getInit(ElementNo))) > + // Otherwise we have a bitfield. > + if (!AppendBitField(*Field, Layout.getFieldOffset(FieldNo), > EltInit)) > return false; > } > - > - ElementNo++; > } > > uint64_t LayoutSizeInBytes = Layout.getSize() / 8; > > Modified: cfe/trunk/test/CodeGen/decl.c > URL: > http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CodeGen/decl.c?rev=101155&r1=101154&r2=101155&view=diff > ============================================================================== > --- cfe/trunk/test/CodeGen/decl.c (original) > +++ cfe/trunk/test/CodeGen/decl.c Tue Apr 13 13:16:19 2010 > @@ -5,7 +5,10 @@ > // CHECK: @test5w = global %0 { i32 2, [4 x i8] zeroinitializer } > // CHECK: @test5y = global %union.test5u { double 7.300000e+0{{[0]*}}1 } > > -// CHECK: @test6.x = internal constant %1 { i8 1, i8 2, i32 3, [4 x i8] > zeroinitializer } > +// CHECK: @test6.x = internal constant %struct.SelectDest { i8 1, i8 2, > i32 3, i32 0 } > + > +// CHECK: @test7 = global [2 x %struct.test7s] [%struct.test7s { i32 1, > i32 2 }, %struct.test7s { i32 4, i32 0 }] > + > void test1() { > // This should codegen as a "@test1.x" global. > const int x[] = { 1, 2, 3, 4, 6, 8, 9, 10, 123, 231, 123,23 }; > @@ -74,3 +77,10 @@ > struct SelectDest x = {1, 2, 3}; > test6f(&x); > } > + > +// rdar://7657600 > +struct test7s { int a; int b; } test7[] = { > + {1, 2}, > + {4}, > +}; > + > > > _______________________________________________ > cfe-commits mailing list > [email protected] > http://lists.cs.uiuc.edu/mailman/listinfo/cfe-commits _______________________________________________ cfe-commits mailing list [email protected] http://lists.cs.uiuc.edu/mailman/listinfo/cfe-commits
