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[BPF] annotate DIType metadata for builtin preseve_array_access_index() Previously, debuginfo types are annotated to IR builtin preserve_struct_access_index() and preserve_union_access_index(), but not preserve_array_access_index(). The debug info is useful to identify the root type name which later will be used for type comparison. For user access without explicit type conversions, the previous scheme works as we can ignore intermediate compiler generated type conversions (e.g., from union types to union members) and still generate correct access index string. The issue comes with user explicit type conversions, e.g., converting an array to a structure like below: struct t { int a; char b[40]; }; struct p { int c; int d; }; struct t *var = ...; ... __builtin_preserve_access_index(&(((struct p *)&(var->b[0]))->d)) ... Although BPF backend can derive the type of &(var->b[0]), explicit type annotation make checking more consistent and less error prone. Another benefit is for multiple dimension array handling. For example, struct p { int c; int d; } g[8][9][10]; ... __builtin_preserve_access_index(&g[2][3][4].d) ... It would be possible to calculate the number of "struct p"'s before accessing its member "d" if array debug info is available as it contains each dimension range. This patch enables to annotate IR builtin preserve_array_access_index() with proper debuginfo type. The unit test case and language reference is updated as well. Signed-off-by: Yonghong Song <yhs@fb.com> Differential Revision: https://reviews.llvm.org/D65664 llvm-svn: 367724
2019-08-03 05:28:28 +08:00
// RUN: %clang -target x86_64 -emit-llvm -S -g %s -o - | FileCheck %s
#define _(x) (__builtin_preserve_access_index(x))
struct s1 {
char a;
int b[4];
};
const void *unit1(struct s1 *arg) {
return _(&arg->b[2]);
}
// CHECK: define dso_local i8* @unit1
// CHECK: call [4 x i32]* @llvm.preserve.struct.access.index.p0a4i32.p0s_struct.s1s(%struct.s1* %{{[0-9a-z]+}}, i32 1, i32 1), !dbg !{{[0-9]+}}, !llvm.preserve.access.index ![[STRUCT_S1:[0-9]+]]
// CHECK: call i32* @llvm.preserve.array.access.index.p0i32.p0a4i32([4 x i32]* %{{[0-9a-z]+}}, i32 1, i32 2), !dbg !{{[0-9]+}}, !llvm.preserve.access.index ![[ARRAY:[0-9]+]]
//
// CHECK: ![[ARRAY]] = !DICompositeType(tag: DW_TAG_array_type
// CHECK: ![[STRUCT_S1]] = distinct !DICompositeType(tag: DW_TAG_structure_type, name: "s1"