AArch64: implement first relocation required for MCJIT

R_AARCH64_PCREL32 is present in even trivial .eh_frame sections and so
is required to compile any function without the "nounwind" attribute.

This change implements very basic infrastructure in the RuntimeDyldELF
file and allows (for example) the test-shift.ll MCJIT test to pass
on AArch64.

llvm-svn: 181131

1 files changed, 6 insertions, 0 deletions

diff --git a/llvm/lib/Target/AArch64/MCTargetDesc/AArch64MCTargetDesc.cpp b/llvm/lib/Target/AArch64/MCTargetDesc/AArch64MCTargetDesc.cpp
index 7960db08c8d..819eeadb44e 100644
--- a/llvm/lib/Target/AArch64/MCTargetDesc/AArch64MCTargetDesc.cpp
+++ b/llvm/lib/Target/AArch64/MCTargetDesc/AArch64MCTargetDesc.cpp
@@ -81,6 +81,12 @@ static MCCodeGenInfo *createAArch64MCCodeGenInfo(StringRef TT, Reloc::Model RM,
 
   if (CM == CodeModel::Default)
     CM = CodeModel::Small;
+  else if (CM == CodeModel::JITDefault) {
+    // The default MCJIT memory managers make no guarantees about where they can
+    // find an executable page; JITed code needs to be able to refer to globals
+    // no matter how far away they are.
+    CM = CodeModel::Large;
+  }
 
   X->InitMCCodeGenInfo(RM, CM, OL);
   return X;