Merge pull request #46 from iovisor/ctx

add ctx builtin

src/ast/codegen_llvm.cpp

@@ -116,6 +116,11 @@ void CodegenLLVM::visit(Builtin &builtin)
     name_id++;
     expr_ = b_.getInt64(builtin.name_id);
   }
+  else if (builtin.ident == "ctx")
+  {
+    // undocumented builtin: for debugging
+    expr_ = ctx_;
+  }
   else
   {
     abort();

src/ast/semantic_analyser.cpp

@@ -34,6 +34,7 @@ void SemanticAnalyser::visit(Builtin &builtin)
       builtin.ident == "cpu" ||
       builtin.ident == "curtask" ||
       builtin.ident == "rand" ||
+      builtin.ident == "ctx" ||
       builtin.ident == "retval") {
     builtin.type = SizedType(Type::integer, 8);
   }

src/lexer.l

@@ -46,7 +46,7 @@ path   :(\\.|[_\-\./a-zA-Z0-9])*:
 <COMMENT>"EOF"          driver.error(loc, std::string("end of file during comment"));
 <COMMENT>.|"\n"         ;
 
-pid|tid|uid|gid|nsecs|cpu|comm|stack|ustack|arg[0-9]|retval|func|name|curtask|rand {
+pid|tid|uid|gid|nsecs|cpu|comm|stack|ustack|arg[0-9]|retval|func|name|curtask|rand|ctx {
                           return Parser::make_BUILTIN(yytext, loc); }
 {path}                  { return Parser::make_PATH(yytext, loc); }
 {map}                   { return Parser::make_MAP(yytext, loc); }

tests/codegen.cpp

@@ -597,6 +597,42 @@ attributes #1 = { argmemonly nounwind }
 )EXPECTED");
 }
 
+TEST(codegen, builtin_ctx)
+{
+  test("kprobe:f { @x = ctx }",
+
+R"EXPECTED(; Function Attrs: nounwind
+declare i64 @llvm.bpf.pseudo(i64, i64) #0
+
+; Function Attrs: argmemonly nounwind
+declare void @llvm.lifetime.start.p0i8(i64, i8* nocapture) #1
+
+define i64 @"kprobe:f"(i8*) local_unnamed_addr section "s_kprobe:f" {
+entry:
+  %"@x_val" = alloca i64, align 8
+  %"@x_key" = alloca i64, align 8
+  %1 = bitcast i64* %"@x_key" to i8*
+  call void @llvm.lifetime.start.p0i8(i64 -1, i8* nonnull %1)
+  store i64 0, i64* %"@x_key", align 8
+  %2 = zext i8* %0 to i64
+  %3 = bitcast i64* %"@x_val" to i8*
+  call void @llvm.lifetime.start.p0i8(i64 -1, i8* nonnull %3)
+  store i64 %2, i64* %"@x_val", align 8
+  %pseudo = tail call i64 @llvm.bpf.pseudo(i64 1, i64 1)
+  %update_elem = call i64 inttoptr (i64 2 to i64 (i8*, i8*, i8*, i64)*)(i64 %pseudo, i64* nonnull %"@x_key", i64* nonnull %"@x_val", i64 0)
+  call void @llvm.lifetime.end.p0i8(i64 -1, i8* nonnull %1)
+  call void @llvm.lifetime.end.p0i8(i64 -1, i8* nonnull %3)
+  ret i64 0
+}
+
+; Function Attrs: argmemonly nounwind
+declare void @llvm.lifetime.end.p0i8(i64, i8* nocapture) #1
+
+attributes #0 = { nounwind }
+attributes #1 = { argmemonly nounwind }
+)EXPECTED");
+}
+
 TEST(codegen, builtin_comm)
 {
   test("kprobe:f { @x = comm }",

tests/parser.cpp

@@ -31,6 +31,7 @@ TEST(Parser, builtin_variables)
   test("kprobe:f { cpu }", "Program\n kprobe:f\n  builtin: cpu\n");
   test("kprobe:f { curtask }", "Program\n kprobe:f\n  builtin: curtask\n");
   test("kprobe:f { rand }", "Program\n kprobe:f\n  builtin: rand\n");
+  test("kprobe:f { ctx }", "Program\n kprobe:f\n  builtin: ctx\n");
   test("kprobe:f { comm }", "Program\n kprobe:f\n  builtin: comm\n");
   test("kprobe:f { stack }", "Program\n kprobe:f\n  builtin: stack\n");
   test("kprobe:f { ustack }", "Program\n kprobe:f\n  builtin: ustack\n");

tests/semantic_analyser.cpp

@@ -59,6 +59,7 @@ TEST(semantic_analyser, builtin_variables)
   test("kprobe:f { cpu }", 0);
   test("kprobe:f { curtask }", 0);
   test("kprobe:f { rand }", 0);
+  test("kprobe:f { ctx }", 0);
   test("kprobe:f { comm }", 0);
   test("kprobe:f { stack }", 0);
   test("kprobe:f { ustack }", 0);