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[BPF] Add preserve_access_index attribute for record definition This is a resubmission for the previous reverted commit 943436040121 with the same subject. This commit fixed the segfault issue and addressed additional review comments. This patch introduced a new bpf specific attribute which can be added to struct or union definition. For example, struct s { ... } __attribute__((preserve_access_index)); union u { ... } __attribute__((preserve_access_index)); The goal is to simplify user codes for cases where preserve access index happens for certain struct/union, so user does not need to use clang __builtin_preserve_access_index for every members. The attribute has no effect if -g is not specified. When the attribute is specified and -g is specified, any member access defined by that structure or union, including array subscript access and inner records, will be preserved through __builtin_preserve_{array,struct,union}_access_index() IR intrinsics, which will enable relocation generation in bpf backend. The following is an example to illustrate the usage: -bash-4.4$ cat t.c #define __reloc__ __attribute__((preserve_access_index)) struct s1 { int c; } __reloc__; struct s2 { union { struct s1 b[3]; }; } __reloc__; struct s3 { struct s2 a; } __reloc__; int test(struct s3 *arg) { return arg->a.b[2].c; } -bash-4.4$ clang -target bpf -g -S -O2 t.c A relocation with access string "0:0:0:0:2:0" will be generated representing access offset of arg->a.b[2].c. forward declaration with attribute is also handled properly such that the attribute is copied and populated in real record definition. Differential Revision: https://reviews.llvm.org/D69759
2019-11-02 13:16:59 +08:00
// REQUIRES: bpf-registered-target
[OpaquePtrs][Clang] Add -no-opaque-pointers to tests (NFC) This adds -no-opaque-pointers to clang tests whose output will change when opaque pointers are enabled by default. This is intended to be part of the migration approach described in https://discourse.llvm.org/t/enabling-opaque-pointers-by-default/61322/9. The patch has been produced by replacing %clang_cc1 with %clang_cc1 -no-opaque-pointers for tests that fail with opaque pointers enabled. Worth noting that this doesn't cover all tests, there's a remaining ~40 tests not using %clang_cc1 that will need a followup change. Differential Revision: https://reviews.llvm.org/D123115
2022-04-07 18:03:55 +08:00
// RUN: %clang_cc1 -no-opaque-pointers -triple bpf -emit-llvm -debug-info-kind=limited -disable-llvm-passes %s -o - | FileCheck %s
[BPF] Add preserve_access_index attribute for record definition This is a resubmission for the previous reverted commit 943436040121 with the same subject. This commit fixed the segfault issue and addressed additional review comments. This patch introduced a new bpf specific attribute which can be added to struct or union definition. For example, struct s { ... } __attribute__((preserve_access_index)); union u { ... } __attribute__((preserve_access_index)); The goal is to simplify user codes for cases where preserve access index happens for certain struct/union, so user does not need to use clang __builtin_preserve_access_index for every members. The attribute has no effect if -g is not specified. When the attribute is specified and -g is specified, any member access defined by that structure or union, including array subscript access and inner records, will be preserved through __builtin_preserve_{array,struct,union}_access_index() IR intrinsics, which will enable relocation generation in bpf backend. The following is an example to illustrate the usage: -bash-4.4$ cat t.c #define __reloc__ __attribute__((preserve_access_index)) struct s1 { int c; } __reloc__; struct s2 { union { struct s1 b[3]; }; } __reloc__; struct s3 { struct s2 a; } __reloc__; int test(struct s3 *arg) { return arg->a.b[2].c; } -bash-4.4$ clang -target bpf -g -S -O2 t.c A relocation with access string "0:0:0:0:2:0" will be generated representing access offset of arg->a.b[2].c. forward declaration with attribute is also handled properly such that the attribute is copied and populated in real record definition. Differential Revision: https://reviews.llvm.org/D69759
2019-11-02 13:16:59 +08:00
#define __reloc__ __attribute__((preserve_access_index))
// chain of records, some do not have attributes.
struct s1 {
int c;
};
typedef struct s1 __s1;
struct s2 {
union {
__s1 b[3];
};
} __reloc__;
typedef struct s2 __s2;
struct s3 {
__s2 a;
};
typedef struct s3 __s3;
int test(__s3 *arg) {
return arg->a.b[2].c;
}
// CHECK: define dso_local i32 @test
// CHECK-NOT: call %struct.s2* @llvm.preserve.struct.access.index.p0s_struct.s2s.p0s_struct.s3s
[BPF] Use elementtype attribute for preserve.array/struct.index intrinsics Use the elementtype attribute introduced in D105407 for the llvm.preserve.array/struct.index intrinsics. It carries the element type of the GEP these intrinsics effectively encode. This patch: * Adds a verifier check that the attribute is required. * Adds it in the IRBuilder methods for these intrinsics. * Autoupgrades old bitcode without the attribute. * Updates the lowering code to use the attribute rather than the pointer element type. * Updates lots of tests to specify the attribute. * Adds -force-opaque-pointers to the intrinsic-array.ll test to demonstrate they work now. https://reviews.llvm.org/D106184
2021-07-17 02:26:40 +08:00
// CHECK: call %union.anon* @llvm.preserve.struct.access.index.p0s_union.anons.p0s_struct.s2s(%struct.s2* elementtype(%struct.s2) %{{[0-9a-z]+}}, i32 0, i32 0)
[BPF] fix clang test failure for bpf-attr-preserve-access-index-4.c Depending on different cmake configures, clang may generate different IR name for slot variables. Let us use the regex instead of hard coding the name. I did the same for other bpf-attr-preserve-access-index tests with such an approach, but somehow did not do for this one.
2019-11-14 01:40:57 +08:00
// CHECK: call %union.anon* @llvm.preserve.union.access.index.p0s_union.anons.p0s_union.anons(%union.anon* %{{[0-9a-z]+}}, i32 0)
[BPF] Use elementtype attribute for preserve.array/struct.index intrinsics Use the elementtype attribute introduced in D105407 for the llvm.preserve.array/struct.index intrinsics. It carries the element type of the GEP these intrinsics effectively encode. This patch: * Adds a verifier check that the attribute is required. * Adds it in the IRBuilder methods for these intrinsics. * Autoupgrades old bitcode without the attribute. * Updates the lowering code to use the attribute rather than the pointer element type. * Updates lots of tests to specify the attribute. * Adds -force-opaque-pointers to the intrinsic-array.ll test to demonstrate they work now. https://reviews.llvm.org/D106184
2021-07-17 02:26:40 +08:00
// CHECK: call %struct.s1* @llvm.preserve.array.access.index.p0s_struct.s1s.p0a3s_struct.s1s([3 x %struct.s1]* elementtype([3 x %struct.s1]) %{{[0-9a-z]+}}, i32 1, i32 2)
[BPF] Add preserve_access_index attribute for record definition This is a resubmission for the previous reverted commit 943436040121 with the same subject. This commit fixed the segfault issue and addressed additional review comments. This patch introduced a new bpf specific attribute which can be added to struct or union definition. For example, struct s { ... } __attribute__((preserve_access_index)); union u { ... } __attribute__((preserve_access_index)); The goal is to simplify user codes for cases where preserve access index happens for certain struct/union, so user does not need to use clang __builtin_preserve_access_index for every members. The attribute has no effect if -g is not specified. When the attribute is specified and -g is specified, any member access defined by that structure or union, including array subscript access and inner records, will be preserved through __builtin_preserve_{array,struct,union}_access_index() IR intrinsics, which will enable relocation generation in bpf backend. The following is an example to illustrate the usage: -bash-4.4$ cat t.c #define __reloc__ __attribute__((preserve_access_index)) struct s1 { int c; } __reloc__; struct s2 { union { struct s1 b[3]; }; } __reloc__; struct s3 { struct s2 a; } __reloc__; int test(struct s3 *arg) { return arg->a.b[2].c; } -bash-4.4$ clang -target bpf -g -S -O2 t.c A relocation with access string "0:0:0:0:2:0" will be generated representing access offset of arg->a.b[2].c. forward declaration with attribute is also handled properly such that the attribute is copied and populated in real record definition. Differential Revision: https://reviews.llvm.org/D69759
2019-11-02 13:16:59 +08:00
// CHECK-NOT: call i32* @llvm.preserve.struct.access.index.p0i32.p0s_struct.s1s