[lld] [lld][LoongArch] Handle extreme code model relocs according to psABI v2.30 (PR #73387)

[Jinyang He via llvm-commits]

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@@ -82,11 +82,29 @@ static uint64_t getLoongArchPage(uint64_t p) {
 static uint32_t lo12(uint32_t val) { return val & 0xfff; }
 
 // Calculate the adjusted page delta between dest and PC.
-uint64_t elf::getLoongArchPageDelta(uint64_t dest, uint64_t pc) {
-  // Compensate all the sign-extensions is a bit complicated. Just use the same
-  // logic as bfd and mold. Note that this algorithm assumes those four
-  // instructions (pcalau12i/addi.d/lu32i.d/lu52i.d) are in the same 4K-page.
-  uint64_t result = getLoongArchPage(dest) - getLoongArchPage(pc);
+uint64_t elf::getLoongArchPageDelta(uint64_t dest, uint64_t pc, RelType type) {
+  // Note that if the sequence being relocated is `pcalau12i + addi.d + lu32i.d
+  // + lu52i.d`, they must be adjancent so that we can infer the PC of
+  // `pcalau12i` when calculating the page delta for the other two instructions
+  // (lu32i.d and lu52i.d). Compensate all the sign-extensions is a bit
+  // complicated. Just use psABI recommended algorithm.
+  uint64_t pcalau12i_pc;
+  switch (type) {
+  case R_LARCH_PCALA64_LO20:
+  case R_LARCH_GOT64_PC_LO20:
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MQ-mengqing wrote:

We might miss to modify the other `{R_LARCH_GOT, R_LARCH_TLS_IE, R_LARCH_TLS_DESC}{64_PC_LO20,64_PC_HI12}` in that doc. Thanks!

https://github.com/llvm/llvm-project/pull/73387