[PGO][Offload] Fix offload coverage mapping (#143490)

This pull request fixes coverage mapping on GPU targets. 

- It adds an address space cast to the coverage mapping generation pass.
- It reads the profiled function names from the ELF directly. Reading it
from public globals was causing issues in cases where multiple
device-code object files are linked together.

1 files changed, 3 insertions, 2 deletions

diff --git a/clang/lib/CodeGen/CoverageMappingGen.cpp b/clang/lib/CodeGen/CoverageMappingGen.cpp
index 1788bb4..4aafac3 100644
--- a/clang/lib/CodeGen/CoverageMappingGen.cpp
+++ b/clang/lib/CodeGen/CoverageMappingGen.cpp
@@ -2622,8 +2622,9 @@ void CoverageMappingModuleGen::emit() {
   CGM.addUsedGlobal(CovData);
   // Create the deferred function records array
   if (!FunctionNames.empty()) {
-    auto NamesArrTy = llvm::ArrayType::get(llvm::PointerType::getUnqual(Ctx),
-                                           FunctionNames.size());
+    auto AddrSpace = FunctionNames.front()->getType()->getPointerAddressSpace();
+    auto NamesArrTy = llvm::ArrayType::get(
+        llvm::PointerType::get(Ctx, AddrSpace), FunctionNames.size());
     auto NamesArrVal = llvm::ConstantArray::get(NamesArrTy, FunctionNames);
     // This variable will *NOT* be emitted to the object file. It is used
     // to pass the list of names referenced to codegen.