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e786f06032
When extern was added, the rv64 code switched regular globals from using la (a pseudo-instruction that uses pc-relative addressing with auipc + addi) to lui + addi (absolute addressing). Presumably, this was done to match gcc's output with -fPIC and -fno-PIC respectively. However, the key difference here is actually the directive `%option pic` vs `%option nopic`, which determines whether la uses the GOT or not. This broke linking as PIE (for instance in compilers with --enable-default-pie), even when there are no global references outside the executable. The other architectures always use pc-relative addressing, so rv64 should do the same. It turns out there are more specific pseudo-instructions lla and lga we can use instead. lla uses auipc+addi, and lga uses auipc+ld from the GOT. lga does not allow an offset. If you try to use one, it will assemble without error, but fail at link time with (.text+0x10): dangerous relocation: The addend isn't allowed for R_RISCV_GOT_HI20 For now, just add a check for this. A proper fix involves some changes to rv64/isel like is done for amd64. |
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| amd64 | ||
| arm64 | ||
| doc | ||
| minic | ||
| rv64 | ||
| test | ||
| tools | ||
| .gitignore | ||
| abi.c | ||
| alias.c | ||
| all.h | ||
| cfg.c | ||
| copy.c | ||
| emit.c | ||
| fold.c | ||
| gcm.c | ||
| gvn.c | ||
| ifopt.c | ||
| LICENSE | ||
| live.c | ||
| load.c | ||
| main.c | ||
| Makefile | ||
| mem.c | ||
| ops.h | ||
| parse.c | ||
| README | ||
| rega.c | ||
| simpl.c | ||
| spill.c | ||
| ssa.c | ||
| util.c | ||
QBE - Backend Compiler http://c9x.me/compile/ doc/ Documentation. minic/ An example C frontend for QBE. tools/ Miscellaneous tools (testing). test/ Tests. amd64/ arm64/ rv64/ Architecture-specific code. The LICENSE file applies to all files distributed. - Compilation and Installation Invoke make in this directory to create the executable file qbe. Install using 'make install', the standard DESTDIR and PREFIX environment variables are supported. Alternatively, you may simply copy the qbe binary.