[PATCH] D152221: Avoid cross-section branches in AArch64 inline asm

[Daniel Hoekwater via Phabricator via llvm-commits]

dhoekwater updated this revision to Diff 528658.
dhoekwater added a comment.

Don't format code we're not touching


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D152221/new/

https://reviews.llvm.org/D152221

Files:
  llvm/lib/CodeGen/BasicBlockSections.cpp
  llvm/lib/CodeGen/MachineFunctionSplitter.cpp


Index: llvm/lib/CodeGen/MachineFunctionSplitter.cpp
===================================================================
--- llvm/lib/CodeGen/MachineFunctionSplitter.cpp
+++ llvm/lib/CodeGen/MachineFunctionSplitter.cpp
@@ -115,6 +115,15 @@
   if (!UseProfileData && !SplitAllEHCode)
     return false;
 
+  // Blocks cannot be split to different sections on AArch64 if they contain
+  // inline assembly. This is because inline assembly may contain a jump to
+  // another block in a different text section, which the compiler can't
+  // guarantee is in-range of the branch instruction.
+  const auto &Triple = MF.getSubtarget().getTargetTriple();
+  assert(Triple.isX86() || Triple.isAArch64());
+  if (Triple.isAArch64() && MF.hasInlineAsm())
+    return false;
+
   // TODO: We don't split functions where a section attribute has been set
   // since the split part may not be placed in a contiguous region. It may also
   // be more beneficial to augment the linker to ensure contiguous layout of
Index: llvm/lib/CodeGen/BasicBlockSections.cpp
===================================================================
--- llvm/lib/CodeGen/BasicBlockSections.cpp
+++ llvm/lib/CodeGen/BasicBlockSections.cpp
@@ -318,9 +318,19 @@
   // clusters of basic blocks using basic block ids. Source drift can
   // invalidate these groupings leading to sub-optimal code generation with
   // regards to performance.
-  if (BBSectionsType == BasicBlockSection::List &&
+  if (BBSectionsType == BasicBlockSection::List && 
       hasInstrProfHashMismatch(MF))
     return true;
+
+  // Blocks cannot be placed in different sections on AArch64 if they contain
+  // inline assembly. This is because inline assembly may contain a jump to
+  // another block in a different text section, which the compiler can't
+  // guarantee is in-range of the branch instruction.
+  const auto &Triple = MF.getSubtarget().getTargetTriple();
+  assert(Triple.isX86() || Triple.isAArch64());
+  if (Triple.isAArch64() && MF.hasInlineAsm())
+    return false;
+
   // Renumber blocks before sorting them. This is useful during sorting,
   // basic blocks in the same section will retain the default order.
   // This renumbering should also be done for basic block labels to match the


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