IRgen/x86_32/Linux: Linux seems to align all stack objects to 4 bytes, unlike
Darwin. Checked vs the handiest Linux llvm-gcc I had around, someone on Linux is
welcome to investigate more.
git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@114112 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/TargetInfo.cpp b/lib/CodeGen/TargetInfo.cpp
index 4d221d4..2ae88f3 100644
--- a/lib/CodeGen/TargetInfo.cpp
+++ b/lib/CodeGen/TargetInfo.cpp
@@ -336,6 +336,8 @@
/// X86_32ABIInfo - The X86-32 ABI information.
class X86_32ABIInfo : public ABIInfo {
+ static const unsigned MinABIStackAlignInBytes = 4;
+
bool IsDarwinVectorABI;
bool IsSmallStructInRegABI;
@@ -349,6 +351,9 @@
/// such that the argument will be passed in memory.
ABIArgInfo getIndirectResult(QualType Ty, bool ByVal = true) const;
+ /// \brief Return the alignment to use for the given type on the stack.
+ unsigned getTypeStackAlignInBytes(QualType Ty) const;
+
public:
ABIArgInfo classifyReturnType(QualType RetTy) const;
@@ -547,15 +552,30 @@
ABIArgInfo::getExtend() : ABIArgInfo::getDirect());
}
+unsigned X86_32ABIInfo::getTypeStackAlignInBytes(QualType Ty) const {
+ // On non-Darwin, the stack type alignment is always 4.
+ if (!IsDarwinVectorABI)
+ return MinABIStackAlignInBytes;
+
+ // Otherwise, if the alignment is less than or equal to 4, use the minimum ABI
+ // alignment.
+ unsigned Align = getContext().getTypeAlign(Ty) / 8;
+ if (Align <= MinABIStackAlignInBytes)
+ return MinABIStackAlignInBytes;
+
+ // Otherwise, if the type contains SSE or MMX vector types, then the alignment
+ // matches that of the struct.
+ return Align;
+}
+
ABIArgInfo X86_32ABIInfo::getIndirectResult(QualType Ty, bool ByVal) const {
if (!ByVal)
return ABIArgInfo::getIndirect(0, false);
// Compute the byval alignment. We trust the back-end to honor the
// minimum ABI alignment for byval, to make cleaner IR.
- const unsigned MinABIAlign = 4;
- unsigned Align = getContext().getTypeAlign(Ty) / 8;
- if (Align > MinABIAlign)
+ unsigned Align = getTypeStackAlignInBytes(Ty);
+ if (Align > MinABIStackAlignInBytes)
return ABIArgInfo::getIndirect(Align);
return ABIArgInfo::getIndirect(0);
}
diff --git a/test/CodeGen/x86_32-arguments-linux.c b/test/CodeGen/x86_32-arguments-linux.c
new file mode 100644
index 0000000..31b184c
--- /dev/null
+++ b/test/CodeGen/x86_32-arguments-linux.c
@@ -0,0 +1,51 @@
+// RUN: %clang_cc1 -w -fblocks -triple i386-pc-linux-gnu -emit-llvm -o %t %s
+// RUN: FileCheck < %t %s
+
+// CHECK: define void @f56(
+// CHECK: i8 signext %a0, %struct.s56_0* byval %a1,
+// CHECK: <2 x i32> %a2, %struct.s56_1* byval %a3,
+// CHECK: <1 x double> %a4, %struct.s56_2* byval %a5,
+// CHECK: <4 x i32> %a6, %struct.s56_3* byval %a7,
+// CHECK: <2 x double> %a8, %struct.s56_4* byval %a9,
+// CHECK: <8 x i32> %a10, %struct.s56_5* byval %a11,
+// CHECK: <4 x double> %a12, %struct.s56_6* byval %a13)
+
+// CHECK: call void (i32, ...)* @f56_0(i32 1,
+// CHECK: i32 %{{.*}}, %struct.s56_0* byval %{{[^ ]*}},
+// CHECK: <2 x i32> %{{[^ ]*}}, %struct.s56_1* byval %{{[^ ]*}},
+// CHECK: <1 x double> %{{[^ ]*}}, %struct.s56_2* byval %{{[^ ]*}},
+// CHECK: <4 x i32> %{{[^ ]*}}, %struct.s56_3* byval %{{[^ ]*}},
+// CHECK: <2 x double> %{{[^ ]*}}, %struct.s56_4* byval %{{[^ ]*}},
+// CHECK: <8 x i32> %{{[^ ]*}}, %struct.s56_5* byval %{{[^ ]*}},
+// CHECK: <4 x double> %{{[^ ]*}}, %struct.s56_6* byval %{{[^ ]*}})
+// CHECK: }
+//
+// <rdar://problem/7964854> [i386] clang misaligns long double in structures
+// when passed byval
+// <rdar://problem/8431367> clang misaligns parameters on stack
+typedef int __attribute__((vector_size (8))) t56_v2i;
+typedef double __attribute__((vector_size (8))) t56_v1d;
+typedef int __attribute__((vector_size (16))) t56_v4i;
+typedef double __attribute__((vector_size (16))) t56_v2d;
+typedef int __attribute__((vector_size (32))) t56_v8i;
+typedef double __attribute__((vector_size (32))) t56_v4d;
+
+struct s56_0 { char a; };
+struct s56_1 { t56_v2i a; };
+struct s56_2 { t56_v1d a; };
+struct s56_3 { t56_v4i a; };
+struct s56_4 { t56_v2d a; };
+struct s56_5 { t56_v8i a; };
+struct s56_6 { t56_v4d a; };
+
+void f56(char a0, struct s56_0 a1,
+ t56_v2i a2, struct s56_1 a3,
+ t56_v1d a4, struct s56_2 a5,
+ t56_v4i a6, struct s56_3 a7,
+ t56_v2d a8, struct s56_4 a9,
+ t56_v8i a10, struct s56_5 a11,
+ t56_v4d a12, struct s56_6 a13) {
+ extern void f56_0(int x, ...);
+ f56_0(1, a0, a1, a2, a3, a4, a5, a6, a7, a8, a9,
+ a10, a11, a12, a13);
+}