[PATCH] D82950: [PowerPC] Support PCRelative Callees for R_PPC64_REL24 Relocation

[Sean Fertile via Phabricator via llvm-commits]

sfertile added inline comments.


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Comment at: lld/ELF/Thunks.cpp:287
+// 1) Saves the TOC pointer to the stack.
+// 2) Branch directly to the callee.
+class PPC64R2SaveStub final : public Thunk {
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anil9 wrote:
> Branch -> Branches/Jumps
Alternatively: `2) Tails calls the callee`


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Comment at: lld/ELF/Thunks.cpp:842
+  write32(buf + 0, 0xf8410018);                         // std  r2,24(r1)
+  write32(buf + 4, 0x48000000 | (offset & 0x03fffffc)); // b    <offset>
+}
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What happens if offset doesn't fit within 26 bits?


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Comment at: lld/ELF/Thunks.cpp:846
+void PPC64R2SaveStub::addSymbols(ThunkSection &isec) {
+  Defined *s = addSymbol(saver.save("__long_branch_" + destination.getName()),
+                         STT_FUNC, 0, isec);
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This is being named the same as a branch extending thunk (ie a trampoline for when the call is too far to represent with a single call instruction). The name we create shoud represent the thunk type, it makes reading disassembly much easier. How about "__toc_save_` instead?


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Comment at: lld/test/ELF/ppc64-error-toc-local-call.s:37
+	b callee                                           # 0x2C
+	#TC_RETURNd8 callee 0
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nit: remove the compiler generated comments.


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Comment at: lld/test/ELF/ppc64-toc-call-to-pcrel.s:62
+  .size global, 4
+
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nit: remove extra blank line.


Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D82950/new/

https://reviews.llvm.org/D82950