[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
diff --git a/llvm/lib/Target/BPF/MCTargetDesc/BPFAsmBackend.cpp b/llvm/lib/Target/BPF/MCTargetDesc/BPFAsmBackend.cpp
index 800700d..e6ea92e 100644
--- a/llvm/lib/Target/BPF/MCTargetDesc/BPFAsmBackend.cpp
+++ b/llvm/lib/Target/BPF/MCTargetDesc/BPFAsmBackend.cpp
@@ -76,6 +76,15 @@
unsigned Idx = IsLittleEndian ? i : Size - i - 1;
Data[Fixup.getOffset() + Idx] = uint8_t(Value >> (i * 8));
}
+ } else if (Fixup.getKind() == FK_PCRel_4) {
+ Value = (uint32_t)((Value - 8) / 8);
+ if (IsLittleEndian) {
+ Data[Fixup.getOffset() + 1] = 0x10;
+ support::endian::write32le(&Data[Fixup.getOffset() + 4], Value);
+ } else {
+ Data[Fixup.getOffset() + 1] = 0x1;
+ support::endian::write32be(&Data[Fixup.getOffset() + 4], Value);
+ }
} else {
assert(Fixup.getKind() == FK_PCRel_2);
Value = (uint16_t)((Value - 8) / 8);