[PATCH] D101336: [LLD][BPF] Add bpf support

[Fangrui Song via Phabricator via llvm-commits]

MaskRay added inline comments.


================
Comment at: lld/ELF/Arch/BPF.cpp:49
+
+RelType BPF::getDynRel(RelType type) const { return type; }
+
----------------
`R_NONE` if no dynamic relocation is expected


================
Comment at: lld/ELF/Arch/BPF.cpp:53
+                        const uint8_t *loc) const {
+  if (type == R_BPF_NONE)
+    return R_NONE;
----------------
See other `Arch/*.cpp`: add switch in getRelExpr and add `error`


================
Comment at: lld/ELF/LTO.cpp:87
 
-  // Always emit a section per function/datum with LTO.
-  c.Options.FunctionSections = true;
-  c.Options.DataSections = true;
+  if (config->emitFuncDataSections) {
+    c.Options.FunctionSections = true;
----------------
Remove the abstraction: `emitFuncDataSections`.

Just test `config->emachine` and config->relocatable.


================
Comment at: lld/test/ELF/bpf-basic.s:2
+// REQUIRES: bpf
+// RUN: echo 'define dso_local i32 @foo() local_unnamed_addr { entry: ret i32 0 }' > %t1.ll
+// RUN: echo 'define dso_local i32 @bar() local_unnamed_addr { entry: ret i32 1 }' > %t2.ll
----------------
Use `split-file %s %t`


================
Comment at: lld/test/ELF/bpf-basic.s:4
+// RUN: echo 'define dso_local i32 @bar() local_unnamed_addr { entry: ret i32 1 }' > %t2.ll
+// RUN: llc -filetype=obj -mtriple=bpfel %t1.ll -o %t3
+// RUN: llc -filetype=obj -mtriple=bpfel %t2.ll -o %t4
----------------
See `riscv-*.s` how I organize the little-endian and big-endian RUN lines.


================
Comment at: lld/test/ELF/bpf-basic.s:6
+// RUN: llc -filetype=obj -mtriple=bpfel %t2.ll -o %t4
+// RUN: ld.lld -relocatable %t3 %t4 -o %t5
+// RUN: llvm-objdump -d --no-show-raw-insn %t5 | FileCheck %s
----------------
`-relocatable` => `-r`


================
Comment at: lld/test/ELF/bpf-lto-basic.s:1
+// REQUIRES: bpf
+// RUN: llvm-as %S/Inputs/bpf-lto-basic-1.ll -o %t1
----------------
move to `test/ELF/lto`

Use `.bc` for bitcode file extension.


================
Comment at: lld/test/ELF/bpf-lto-basic.s:10
+// CHECK:       <bar>:
+// CHECK:       call {{[0-9]+}}
+// CHECK:       call -1
----------------
`[[#]]`


================
Comment at: lld/test/ELF/bpf-lto-basic.s:17
+
+// BTF:         9feb0100
+// BTF-NOT:     9feb0100
----------------
Add a comment what the magic value is.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D101336/new/

https://reviews.llvm.org/D101336