[lldb] Fix evaluation of expressions with static initializers (#89063)

After 281d71604f418eb952e967d9dc4b26241b7f96a, llvm generates 32-bit
relocations, which overflow when we load these objects into high memory.
Interestingly, setting the code model to "large" does not help here
(perhaps it is the default?). I'm not completely sure that this is the
right thing to do, but it doesn't seem to cause any ill effects. I'll
follow up with the author of that patch about the expected behavior
here.

1 files changed, 6 insertions, 2 deletions

diff --git a/lldb/source/Expression/IRExecutionUnit.cpp b/lldb/source/Expression/IRExecutionUnit.cpp
index cb9bee8733e1..7ad0e5ff22b2 100644
--- a/lldb/source/Expression/IRExecutionUnit.cpp
+++ b/lldb/source/Expression/IRExecutionUnit.cpp
@@ -13,6 +13,7 @@
 #include "llvm/IR/DiagnosticInfo.h"
 #include "llvm/IR/LLVMContext.h"
 #include "llvm/IR/Module.h"
+#include "llvm/Support/CodeGen.h"
 #include "llvm/Support/SourceMgr.h"
 #include "llvm/Support/raw_ostream.h"
 
@@ -279,10 +280,13 @@ void IRExecutionUnit::GetRunnableInfo(Status &error, lldb::addr_t &func_addr,
   llvm::EngineBuilder builder(std::move(m_module_up));
   llvm::Triple triple(m_module->getTargetTriple());
 
+  // PIC needed for ELF to avoid generating 32-bit relocations (which overflow
+  // if the object is loaded into high memory).
+  bool want_pic = triple.isOSBinFormatMachO() || triple.isOSBinFormatELF();
+
   builder.setEngineKind(llvm::EngineKind::JIT)
       .setErrorStr(&error_string)
-      .setRelocationModel(triple.isOSBinFormatMachO() ? llvm::Reloc::PIC_
-                                                      : llvm::Reloc::Static)
+      .setRelocationModel(want_pic ? llvm::Reloc::PIC_ : llvm::Reloc::Static)
       .setMCJITMemoryManager(std::make_unique<MemoryManager>(*this))
       .setOptLevel(llvm::CodeGenOptLevel::Less);