maxjhandsome
/
llvm-project
forked from OSchip/llvm-project
1
0
Fork 0
Code Issues Pull Requests Packages Releases Wiki Activity
llvm-project/llvm/test/CodeGen/BPF/fi_ri.ll

26 lines
737 B
LLVM
Raw Normal View History

[bpf] allow direct and indirect calls kernel verifier is becoming smarter and soon will support direct and indirect function calls. Remove obsolete error from BPF backend. Make call to use PCRel_4 fixup. 'bpf to bpf' calls are distinguished from 'bpf to kernel' calls by insn->src_reg == BPF_PSEUDO_CALL == 1 which is used as relocation indicator similar to ld_imm64->src_reg == BPF_PSEUDO_MAP_FD == 1 The actual 'call' instruction remains the same for both 'bpf to kernel' and 'bpf to bpf' calls. Signed-off-by: Alexei Starovoitov <ast@kernel.org> llvm-svn: 318614
2017-11-19 09:35:00 +08:00
; RUN: llc < %s -march=bpf | FileCheck %s
[bpf] Avoid extra pointer arithmetic for stack access For the program like below struct key_t { int pid; char name[16]; }; extern void test1(char *); int test() { struct key_t key = {}; test1(key.name); return 0; } For key.name, the llc/bpf may generate the below code: R1 = R10 // R10 is the frame pointer R1 += -24 // framepointer adjustment R1 |= 4 // R1 is then used as the first parameter of test1 OR operation is not recognized by in-kernel verifier. This patch introduces an intermediate FI_ri instruction and generates the following code that can be properly verified: R1 = R10 R1 += -20 Patch by Yonghong Song <yhs@plumgrid.com> llvm-svn: 249371
2015-10-06 12:00:53 +08:00
%struct.key_t = type { i32, [16 x i8] }
; Function Attrs: nounwind uwtable
define i32 @test() #0 {
%key = alloca %struct.key_t, align 4
%1 = bitcast %struct.key_t* %key to i8*
convert bpf assembler to look like kernel verifier output since bpf instruction set was introduced people learned to read and understand kernel verifier output whereas llvm asm output stayed obscure and unknown. Convert llvm to emit assembler text similar to kernel to avoid this discrepancy Signed-off-by: Alexei Starovoitov <ast@kernel.org> llvm-svn: 287300
2016-11-18 10:32:35 +08:00
; CHECK: r1 = 0
; CHECK: *(u32 *)(r10 - 8) = r1
; CHECK: *(u64 *)(r10 - 16) = r1
; CHECK: *(u64 *)(r10 - 24) = r1
[bpf] Avoid extra pointer arithmetic for stack access For the program like below struct key_t { int pid; char name[16]; }; extern void test1(char *); int test() { struct key_t key = {}; test1(key.name); return 0; } For key.name, the llc/bpf may generate the below code: R1 = R10 // R10 is the frame pointer R1 += -24 // framepointer adjustment R1 |= 4 // R1 is then used as the first parameter of test1 OR operation is not recognized by in-kernel verifier. This patch introduces an intermediate FI_ri instruction and generates the following code that can be properly verified: R1 = R10 R1 += -20 Patch by Yonghong Song <yhs@plumgrid.com> llvm-svn: 249371
2015-10-06 12:00:53 +08:00
call void @llvm.memset.p0i8.i64(i8* %1, i8 0, i64 20, i32 4, i1 false)
convert bpf assembler to look like kernel verifier output since bpf instruction set was introduced people learned to read and understand kernel verifier output whereas llvm asm output stayed obscure and unknown. Convert llvm to emit assembler text similar to kernel to avoid this discrepancy Signed-off-by: Alexei Starovoitov <ast@kernel.org> llvm-svn: 287300
2016-11-18 10:32:35 +08:00
; CHECK: r1 = r10
; CHECK: r1 += -20
[bpf] Avoid extra pointer arithmetic for stack access For the program like below struct key_t { int pid; char name[16]; }; extern void test1(char *); int test() { struct key_t key = {}; test1(key.name); return 0; } For key.name, the llc/bpf may generate the below code: R1 = R10 // R10 is the frame pointer R1 += -24 // framepointer adjustment R1 |= 4 // R1 is then used as the first parameter of test1 OR operation is not recognized by in-kernel verifier. This patch introduces an intermediate FI_ri instruction and generates the following code that can be properly verified: R1 = R10 R1 += -20 Patch by Yonghong Song <yhs@plumgrid.com> llvm-svn: 249371
2015-10-06 12:00:53 +08:00
%2 = getelementptr inbounds %struct.key_t, %struct.key_t* %key, i64 0, i32 1, i64 0
convert bpf assembler to look like kernel verifier output since bpf instruction set was introduced people learned to read and understand kernel verifier output whereas llvm asm output stayed obscure and unknown. Convert llvm to emit assembler text similar to kernel to avoid this discrepancy Signed-off-by: Alexei Starovoitov <ast@kernel.org> llvm-svn: 287300
2016-11-18 10:32:35 +08:00
; CHECK: call test1
[bpf] Avoid extra pointer arithmetic for stack access For the program like below struct key_t { int pid; char name[16]; }; extern void test1(char *); int test() { struct key_t key = {}; test1(key.name); return 0; } For key.name, the llc/bpf may generate the below code: R1 = R10 // R10 is the frame pointer R1 += -24 // framepointer adjustment R1 |= 4 // R1 is then used as the first parameter of test1 OR operation is not recognized by in-kernel verifier. This patch introduces an intermediate FI_ri instruction and generates the following code that can be properly verified: R1 = R10 R1 += -20 Patch by Yonghong Song <yhs@plumgrid.com> llvm-svn: 249371
2015-10-06 12:00:53 +08:00
call void @test1(i8* %2) #3
ret i32 0
}
; Function Attrs: nounwind argmemonly
declare void @llvm.memset.p0i8.i64(i8* nocapture, i8, i64, i32, i1) #1
declare void @test1(i8*) #2