[BPF] rename 'arena' to 'address_space' (#85161)

There are a few places where `arena` name is used for pointers in
non-zero address space in BPF backend, rename these to use a more
generic `address_space`:
- macro `__BPF_FEATURE_ARENA_CAST` -> `__BPF_FEATURE_ADDR_SPACE_CAST
- name for arena global variables section `.arena.N` ->
`.addr_space.N`

Author: eddyz87

clang/lib/Basic/Targets/BPF.cpp

@@ -36,7 +36,7 @@ void BPFTargetInfo::getTargetDefines(const LangOptions &Opts,
     return;
   }
 
-  Builder.defineMacro("__BPF_FEATURE_ARENA_CAST");
+  Builder.defineMacro("__BPF_FEATURE_ADDR_SPACE_CAST");
 
   if (CPU.empty() || CPU == "generic" || CPU == "v1") {
     Builder.defineMacro("__BPF_CPU_VERSION__", "1");

clang/test/Preprocessor/bpf-predefined-macros.c

@@ -61,7 +61,7 @@ int r;
 #ifdef __BPF_FEATURE_ST
 int s;
 #endif
-#ifdef __BPF_FEATURE_ARENA_CAST
+#ifdef __BPF_FEATURE_ADDR_SPACE_CAST
 int t;
 #endif
 

llvm/lib/Target/BPF/BPFCheckAndAdjustIR.cpp

@@ -15,7 +15,7 @@
 //   - remove llvm.bpf.getelementptr.and.load builtins.
 //   - remove llvm.bpf.getelementptr.and.store builtins.
 //   - for loads and stores with base addresses from non-zero address space
-//     cast base address to zero address space (support for BPF arenas).
+//     cast base address to zero address space (support for BPF address spaces).
 //
 //===----------------------------------------------------------------------===//
 
@@ -482,15 +482,15 @@ static void aspaceWrapOperand(DenseMap<Value *, Value *> &Cache, Instruction *I,
   }
 }
 
-// Support for BPF arenas:
+// Support for BPF address spaces:
 // - for each function in the module M, update pointer operand of
 //   each memory access instruction (load/store/cmpxchg/atomicrmw)
 //   by casting it from non-zero address space to zero address space, e.g:
 //
 //   (load (ptr addrspace (N) %p) ...)
 //     -> (load (addrspacecast ptr addrspace (N) %p to ptr))
 //
-// - assign section with name .arena.N for globals defined in
+// - assign section with name .addr_space.N for globals defined in
 //   non-zero address space N
 bool BPFCheckAndAdjustIR::insertASpaceCasts(Module &M) {
   bool Changed = false;
@@ -517,13 +517,13 @@ bool BPFCheckAndAdjustIR::insertASpaceCasts(Module &M) {
     Changed |= !CastsCache.empty();
   }
   // Merge all globals within same address space into single
-  // .arena.<addr space no> section
+  // .addr_space.<addr space no> section
   for (GlobalVariable &G : M.globals()) {
     if (G.getAddressSpace() == 0 || G.hasSection())
       continue;
     SmallString<16> SecName;
     raw_svector_ostream OS(SecName);
-    OS << ".arena." << G.getAddressSpace();
+    OS << ".addr_space." << G.getAddressSpace();
     G.setSection(SecName);
     // Prevent having separate section for constants
     G.setConstant(false);

llvm/test/CodeGen/BPF/addr-space-globals.ll

@@ -18,7 +18,7 @@
 
 ; Verify that a,b,c reside in the same section
 
-; CHECK:     .section .arena.272,"aw",@progbits
+; CHECK:     .section .addr_space.272,"aw",@progbits
 ; CHECK-NOT: .section
 ; CHECK:     .globl  a
 ; CHECK:     .ascii  "\001\002"

llvm/test/CodeGen/BPF/addr-space-globals2.ll

@@ -14,12 +14,12 @@
 
 ; Verify that a,b reside in separate sections
 
-; CHECK:     .section .arena.1,"aw",@progbits
+; CHECK:     .section .addr_space.1,"aw",@progbits
 ; CHECK-NOT: .section
 ; CHECK:     .globl  a
 ; CHECK:     .ascii  "\001\002"
 
-; CHECK:     .section .arena.2,"aw",@progbits
+; CHECK:     .section .addr_space.2,"aw",@progbits
 ; CHECK-NOT: .section
 ; CHECK:     .globl  b
 ; CHECK:     .ascii  "\003\004"