[BPF][CLANG] Front-end support for __BPF_FEATURE_ARENA_CAST macro

`__BPF_FEATURE_ARENA_CAST` macro is defined if compiler supports emission of `cast_kern` and `cast_user` BPF instructions.
llvm · Mar 8, 2024 · 1b29cfe · 1b29cfe
1 parent e8b41ad
commit 1b29cfe
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Showing 2 changed files with 11 additions and 0 deletions.
diff --git a/clang/lib/Basic/Targets/BPF.cpp b/clang/lib/Basic/Targets/BPF.cpp
@@ -35,6 +35,9 @@ void BPFTargetInfo::getTargetDefines(const LangOptions &Opts,
     Builder.defineMacro("__BPF_CPU_VERSION__", "0");
     return;
   }
+
+  Builder.defineMacro("__BPF_FEATURE_ARENA_CAST");
+
   if (CPU.empty() || CPU == "generic" || CPU == "v1") {
     Builder.defineMacro("__BPF_CPU_VERSION__", "1");
     return;

diff --git a/clang/test/Preprocessor/bpf-predefined-macros.c b/clang/test/Preprocessor/bpf-predefined-macros.c
@@ -61,6 +61,9 @@ int r;
 #ifdef __BPF_FEATURE_ST
 int s;
 #endif
+#ifdef __BPF_FEATURE_ARENA_CAST
+int t;
+#endif
 
 // CHECK: int b;
 // CHECK: int c;
@@ -90,6 +93,11 @@ int s;
 // CPU_V4: int r;
 // CPU_V4: int s;
 
+// CPU_V1: int t;
+// CPU_V2: int t;
+// CPU_V3: int t;
+// CPU_V4: int t;
+
 // CPU_GENERIC: int g;
 
 // CPU_PROBE: int f;