OSchip
/
llvm-project
mirror of https://github.com/THU-DSP-LAB/llvm-project.git
13
0
Fork 6
Code Issues Packages Projects Releases Wiki Activity

[BPF] emit BTF sections only if debuginfo available 

Currently, without -g, BTF sections may still be emitted with
data sections, e.g., for linux kernel bpf selftest
test_tcp_check_syncookie_kern.c issue discovered by Martin
as shown below.

-bash-4.4$ bpftool btf dump file test_tcp_check_syncookie_kern.o
[1] VAR 'results' type_id=0, linkage=global-alloc
[2] VAR '_license' type_id=0, linkage=global-alloc
[3] DATASEC 'license' size=0 vlen=1
        type_id=2 offset=0 size=4
[4] DATASEC 'maps' size=0 vlen=1
        type_id=1 offset=0 size=28

Let disable BTF generation if no debuginfo, which is
the original design.

Signed-off-by: Yonghong Song <yhs@fb.com>

Differential Revision: https://reviews.llvm.org/D61826

llvm-svn: 360556
This commit is contained in:
Yonghong Song 2019-05-13 05:00:23 +00:00
parent 4513929094
commit 98fe9c9869
2 changed files with 33 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
llvm/lib/Target/BPF/BPFAsmPrinter.cpp
View File

@ -54,7 +54,8 @@ public:
bool BPFAsmPrinter::doInitialization(Module &M) {
AsmPrinter::doInitialization(M);
if (MAI->doesSupportDebugInformation()) {
// Only emit BTF when debuginfo available.
if (MAI->doesSupportDebugInformation() && !empty(M.debug_compile_units())) {
Handlers.emplace_back(llvm::make_unique<BTFDebug>(this), "emit",
"Debug Info Emission", "BTF", "BTF Emission");
}

31
llvm/test/CodeGen/BPF/BTF/char-no-debuginfo.ll Normal file
View File

@ -0,0 +1,31 @@
; RUN: llc -march=bpfel -filetype=asm -o - %s | FileCheck -check-prefixes=CHECK %s
; RUN: llc -march=bpfeb -filetype=asm -o - %s | FileCheck -check-prefixes=CHECK %s
; Source code:
; int g __attribute__((section("maps"))) = 5;
; int test() { return g; }
; Compilation flag:
; clang -target bpf -O2 -S -emit-llvm t.c
@g = dso_local local_unnamed_addr global i32 5, section "maps", align 4
; Function Attrs: norecurse nounwind readonly
define dso_local i32 @test() local_unnamed_addr #0 {
%1 = load i32, i32* @g, align 4, !tbaa !2
ret i32 %1
}
; CHECK-NOT: .section .BTF
; CHECK-NOT: .section .BTF.ext
attributes #0 = { norecurse nounwind readonly "correctly-rounded-divide-sqrt-fp-math"="false" "disable-tail-calls"="false" "less-precise-fpmad"="false" "no-frame-pointer-elim"="true" "no-frame-pointer-elim-non-leaf" "no-infs-fp-math"="false" "no-jump-tables"="false" "no-nans-fp-math"="false" "no-signed-zeros-fp-math"="false" "no-trapping-math"="false" "stack-protector-buffer-size"="8" "unsafe-fp-math"="false" "use-soft-float"="false" }
!llvm.module.flags = !{!0}
!llvm.ident = !{!1}
!0 = !{i32 1, !"wchar_size", i32 4}
!1 = !{!"clang version 8.0.20181009 "}
!2 = !{!3, !3, i64 0}
!3 = !{!"int", !4, i64 0}
!4 = !{!"omnipotent char", !5, i64 0}
!5 = !{!"Simple C/C++ TBAA"}