[cfe-commits] r101155 - in /cfe/trunk:lib/CodeGen/CGExprConstant.cpp test/CodeGen/decl.c
Nuno Lopes
nunoplopes at sapo.pt
Tue Apr 13 15:04:03 PDT 2010
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" <sabre at nondot.org>
To: <cfe-commits at cs.uiuc.edu>
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},
> +};
> +
>
>
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