[llvm-branch-commits] [lld] [ELF][PowerPC] Don't assume TOC pointer is valid in IPLT entries (PR #207555)

[Fangrui Song via llvm-branch-commits]

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@@ -1326,34 +1327,52 @@ void elf::writePPC32PltCallStub(Ctx &ctx, uint8_t *buf, uint64_t gotPltVA,
     return;
   }
   uint32_t offset;
-  if (addend >= 0x8000) {
+  uint32_t reg;
+  if (!addend) {
+    // We're a (position-independent) IPLT entry, so cannot assume anything
+    // about what value the caller left in r30 as this could be an indirect
+    // call.
+    write32(ctx, buf + 0, 0x7c0802a6);  //    mflr r0
+    write32(ctx, buf + 4, 0x429f0005);  //    bcl 20, 31, 1f
+    write32(ctx, buf + 8, 0x7d6802a6);  // 1: mflr r11
+    write32(ctx, buf + 12, 0x7c0803a6); //    mtlr r0
+    offset = gotPltVA - p - 8;
+    reg = 11;
+    buf += 16;
+    p += 16;
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MaskRay wrote:

Is this dead?

https://github.com/llvm/llvm-project/pull/207555