Skip to content

[lld][Xtensa] Apply the in-place addend for R_XTENSA_32 #130

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
MabezDev wants to merge 1 commit into
base: release/esp_21.x
Choose a base branch
from
+11 −1
Open

[lld][Xtensa] Apply the in-place addend for R_XTENSA_32 #130

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
12 changes: 11 additions & 1 deletion lld/ELF/Arch/Xtensa.cpp
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -138,7 +138,17 @@ static inline bool isLoop(uint8_t *loc) {
void Xtensa::relocate(uint8_t *loc, const Relocation &rel, uint64_t val) const {
switch (rel.type) {
case R_XTENSA_32:
write32le(loc, val);
// R_XTENSA_32 is a partial_inplace relocation (GNU bfd howto:
// src_mask = dst_mask = 0xffffffff). The GNU Xtensa assembler stores the
// addend in the relocated word itself and leaves the RELA r_addend as 0,
// so the result must be S + r_addend + <existing contents>. Objects from
// the LLVM Xtensa backend keep the addend in r_addend and zero the field,
// so reading the contents back adds 0 and is harmless. Plain
// write32le(loc, val) drops the in-place addend, which miscomputes every
// R_XTENSA_32 with a nonzero addend -- e.g. the switch jump tables in the
// precompiled Espressif Wi-Fi blobs, which then point at a section base
// instead of the intended in-section offset.
write32le(loc, val + read32le(loc));
break;
case R_XTENSA_SLOT0_OP: {
// HACK: calculate the instruction location based on the PC-relative
Expand Down
Loading