[PATCH] D71621: [ELF][PPC32] Implement IPLT code sequence for non-preemptible IFUNC

[Fangrui Song via Phabricator via llvm-commits]

MaskRay created this revision.
Herald added subscribers: llvm-commits, jsji, kbarton, arichardson, nemanjai, emaste.
Herald added a reviewer: espindola.
Herald added a project: LLVM.

Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D71621

Files:
  lld/ELF/Arch/PPC.cpp


Index: lld/ELF/Arch/PPC.cpp
===================================================================
--- lld/ELF/Arch/PPC.cpp
+++ lld/ELF/Arch/PPC.cpp
@@ -35,6 +35,8 @@
                 int32_t index) const override {
     llvm_unreachable("should call writePPC32GlinkSection() instead");
   }
+  void writeIplt(uint8_t *buf, uint64_t gotPltEntryAddr, uint64_t pltEntryAddr,
+                 int32_t index) const override;
   void writeGotPlt(uint8_t *buf, const Symbol &s) const override;
   bool needsThunk(RelExpr expr, RelType relocType, const InputFile *file,
                   uint64_t branchAddr, const Symbol &s,
@@ -144,7 +146,7 @@
   gotPltHeaderEntriesNum = 0;
   pltHeaderSize = 64; // size of PLTresolve in .glink
   pltEntrySize = 4;
-  ipltEntrySize = 4;
+  ipltEntrySize = 16;
 
   needsThunks = true;
 
@@ -158,6 +160,20 @@
   write32(trapInstr.data(), 0x7fe00008);
 }
 
+void PPC::writeIplt(uint8_t *buf, uint64_t gotPltEntryAddr,
+  uint64_t pltEntryAddr, int32_t index) const {
+  uint64_t va = gotPltEntryAddr;
+  // !config->isPic
+  write32(buf + 0, 0x3d600000 | (va + 0x8000) >> 16); // lis r11,ha
+  write32(buf + 4, 0x816b0000 | (uint16_t)va);        // lwz r11,l(r11)
+  write32(buf + 8, 0x7d6903a6);                       // mtctr r11
+  write32(buf + 12, 0x4e800420);                      // bctr
+
+  // config->isPic
+  // file->ppc32Got2OutSecOff is not known.
+  // See Thunks.cpp PPC32PltCallStub::writeTo
+}
+
 void PPC::writeGotHeader(uint8_t *buf) const {
   // _GLOBAL_OFFSET_TABLE_[0] = _DYNAMIC
   // glibc stores _dl_runtime_resolve in _GLOBAL_OFFSET_TABLE_[1],


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