Merge branch 'master' into patch-12

bpftrace · Apr 2, 2022 · fcb70ad · fcb70ad
2 parents afa7801 + 9382ad1
commit fcb70ad
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diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -19,6 +19,8 @@ and this project adheres to
   - [#2147](https://github.com/iovisor/bpftrace/pull/2147)
 - Improve include paths resolution
   - [#2149](https://github.com/iovisor/bpftrace/pull/2149)
+- Add builtin function: `bswap`
+  - [#2166](https://github.com/iovisor/bpftrace/pull/2166)
 
 #### Changed
 #### Deprecated

diff --git a/docs/reference_guide.md b/docs/reference_guide.md
@@ -2222,6 +2222,7 @@ Tracing block I/O sizes > 0 bytes
 - `uptr(void *p)` - Annotate as userspace pointer
 - `kptr(void *p)` - Annotate as kernelspace pointer
 - `macaddr(char[6] addr)` - Convert MAC address data
+- `bswap(uint[8|16|32|64] n)` - Reverse byte order
 
 Some of these are asynchronous: the kernel queues the event, but some time later (milliseconds) it is
 processed in user-space. The asynchronous actions are: `printf()`, `time()`, and `join()`. Both `ksym()`
@@ -3122,6 +3123,21 @@ Attaching 1 probe...
 unified:/user.slice/user-1000.slice/session-3.scope
 ```
 
+## 30. `bswap`: Reverse byte order
+
+Syntax: `bswap(uint[8|16|32|64] n)`
+
+Reverses the order of the bytes in integer `n`. In case of 8 bit integers, `n` is returned without being modified.
+The return type is an unsigned integer of the same width as `n`.
+
+Example:
+
+```
+# bpftrace -e 'BEGIN { $i = (uint32)0x12345678; printf("Reversing byte order of 0x%x ==> 0x%x\n", $i, bswap($i)); }'
+Attaching 1 probe...
+Reversing byte order of 0x12345678 ==> 0x78563412
+```
+
 # Map Functions
 
 Maps are special BPF data types that can be used to store counts, statistics, and histograms. They are
@@ -3632,4 +3648,5 @@ bpftrace requires kernel headers for certain features, which are searched for by
 /lib/modules/$(uname -r)
 ```
 
-The default search directory can be overridden using the environment variable `BPFTRACE_KERNEL_SOURCE`.
+The default search directory can be overridden using the environment variable `BPFTRACE_KERNEL_SOURCE`, and
+also `BPFTRACE_KERNEL_BUILD` if it is out-of-tree Linux kernel build.
diff --git a/man/adoc/bpftrace.adoc b/man/adoc/bpftrace.adoc
@@ -1250,6 +1250,17 @@ Functions that are marked *async* are asynchronous which can lead to unexpected
 
 *unsafe* functions can have dangerous side effects and should be used with care, the `--unsafe` flag is required for use.
 
+=== bswap
+
+.variants
+* `uint8 bswap(uint8 n)`
+* `uint16 bswap(uint16 n)`
+* `uint32 bswap(uint32 n)`
+* `uint64 bswap(uint64 n)`
+
+`bswap` reverses the order of the bytes in integer `n`. In case of 8 bit integers, `n` is returned without being modified.
+The return type is an unsigned integer of the same width as `n`.
+
 === buf
 
 .variants

diff --git a/src/ast/passes/codegen_llvm.cpp b/src/ast/passes/codegen_llvm.cpp
@@ -1092,6 +1092,22 @@ void CodegenLLVM::visit(Call &call)
     b_.CreateLifetimeEnd(buf);
     expr_ = nullptr;
   }
+  else if (call.func == "bswap")
+  {
+    bpftrace::ast::Expression *arg = call.vargs->at(0);
+    auto scoped_del_arg = accept(arg);
+
+    assert(arg->type.IsIntegerTy());
+    if (arg->type.GetSize() > 1)
+    {
+      llvm::Type *arg_type = b_.GetType(arg->type);
+      Function *swap_fun = Intrinsic::getDeclaration(module_.get(),
+                                                     Intrinsic::bswap,
+                                                     { arg_type });
+
+      expr_ = b_.CreateCall(swap_fun, { expr_ });
+    }
+  }
   else
   {
     LOG(FATAL) << "missing codegen for function \"" << call.func << "\"";
@@ -3286,9 +3302,7 @@ void CodegenLLVM::probereadDatastructElem(Value *src_data,
       AllocaInst *dst = b_.CreateAllocaBPF(elem_type, temp_name);
       b_.CreateProbeRead(
           ctx_, dst, elem_type.GetSize(), src, data_type.GetAS(), loc);
-      expr_ = b_.CreateIntCast(b_.CreateLoad(b_.GetType(elem_type), dst),
-                               b_.getInt64Ty(),
-                               elem_type.IsSigned());
+      expr_ = b_.CreateLoad(b_.GetType(elem_type), dst);
       b_.CreateLifetimeEnd(dst);
     }
   }

diff --git a/src/ast/passes/semantic_analyser.cpp b/src/ast/passes/semantic_analyser.cpp
@@ -1260,6 +1260,22 @@ void SemanticAnalyser::visit(Call &call)
     // Return type cannot be used
     call.type = SizedType(Type::none, 0);
   }
+  else if (call.func == "bswap")
+  {
+    if (!check_nargs(call, 1))
+      return;
+
+    Expression *arg = call.vargs->at(0);
+    if (arg->type.type != Type::integer)
+    {
+      LOG(ERROR, call.loc, err_)
+          << call.func << "() only supports integer arguments ("
+          << arg->type.type << " provided)";
+      return;
+    }
+
+    call.type = CreateUInt(arg->type.GetIntBitWidth());
+  }
   else
   {
     LOG(ERROR, call.loc, err_) << "Unknown function: '" << call.func << "'";

diff --git a/src/attached_probe.cpp b/src/attached_probe.cpp
@@ -676,9 +676,8 @@ void AttachedProbe::load_prog()
 
   uint64_t log_buf_size = probe_.log_size;
   auto log_buf = std::make_unique<char[]>(log_buf_size);
-  char name[STRING_SIZE];
-  const char *namep;
-  std::string tracing_type, tracing_name;
+  std::string name;
+  std::string tracing_type;
 
   {
     // Redirect stderr, so we don't get error messages from BCC
@@ -694,16 +693,13 @@ void AttachedProbe::load_prog()
 
     // Use orig_name for program name so we get proper name for
     // wildcard probes, replace wildcards with '.'
-    std::string orig_name = probe_.orig_name;
-    std::replace(orig_name.begin(), orig_name.end(), '*', '.');
-
-    strncpy(name, orig_name.c_str(), STRING_SIZE - 1);
-    namep = name;
+    name = probe_.orig_name;
+    std::replace(name.begin(), name.end(), '*', '.');
 
     // bpf_prog_load rejects colons in the probe name,
     // so start the name after the probe type, after ':'
-    if (strrchr(name, ':') != NULL)
-      namep = strrchr(name, ':') + 1;
+    if (auto last_colon = name.rfind(':'); last_colon != std::string::npos)
+      name = name.substr(last_colon + 1);
 
     // The bcc_prog_load function now recognizes 'kfunc__/kretfunc__'
     // prefixes and detects and fills in all the necessary BTF related
@@ -715,8 +711,7 @@ void AttachedProbe::load_prog()
       if (tracing_type == "iter")
         tracing_type = "bpf_iter";
 
-      tracing_name = tracing_type + "__" + namep;
-      namep = tracing_name.c_str();
+      name = tracing_type + "__" + name;
     }
 
     for (int attempt = 0; attempt < 3; attempt++)
@@ -735,7 +730,7 @@ void AttachedProbe::load_prog()
       struct bpf_load_program_attr attr = {};
 
       attr.prog_type = progtype(probe_.type);
-      attr.name = namep;
+      attr.name = name.c_str();
       attr.insns = reinterpret_cast<struct bpf_insn *>(insns);
       attr.license = license;
 
@@ -754,10 +749,10 @@ void AttachedProbe::load_prog()
 #else // HAVE_BCC_PROG_LOAD_XATTR
 #ifdef HAVE_BCC_PROG_LOAD
       progfd_ = bcc_prog_load(progtype(probe_.type),
-                              namep,
+                              name.c_str(),
 #else
       progfd_ = bpf_prog_load(progtype(probe_.type),
-                              namep,
+                              name.c_str(),
 #endif
                               reinterpret_cast<struct bpf_insn *>(insns),
                               prog_len,

diff --git a/src/lexer.l b/src/lexer.l
@@ -38,7 +38,7 @@ vspace   [\n\r]
 space    {hspace}|{vspace}
 path     :(\\.|[_\-\./a-zA-Z0-9#\*])+
 builtin  arg[0-9]|args|cgroup|comm|cpid|numaid|cpu|ctx|curtask|elapsed|func|gid|nsecs|pid|probe|rand|retval|sarg[0-9]|tid|uid|username
-call     avg|buf|cat|cgroupid|clear|count|delete|exit|hist|join|kaddr|kptr|ksym|lhist|macaddr|max|min|ntop|override|print|printf|cgroup_path|reg|signal|sizeof|stats|str|strftime|strncmp|sum|system|time|uaddr|uptr|usym|zero|path|unwatch
+call     avg|buf|cat|cgroupid|clear|count|delete|exit|hist|join|kaddr|kptr|ksym|lhist|macaddr|max|min|ntop|override|print|printf|cgroup_path|reg|signal|sizeof|stats|str|strftime|strncmp|sum|system|time|uaddr|uptr|usym|zero|path|unwatch|bswap
 
 /* Don't add to this! Use builtin OR call not both */
 call_and_builtin kstack|ustack

diff --git a/src/utils.cpp b/src/utils.cpp
@@ -551,7 +551,14 @@ std::tuple<std::string, std::string> get_kernel_dirs(
 
   const char *kpath_env = ::getenv("BPFTRACE_KERNEL_SOURCE");
   if (kpath_env)
-    return std::make_tuple(kpath_env, kpath_env);
+  {
+    const char *kpath_build_env = ::getenv("BPFTRACE_KERNEL_BUILD");
+    if (!kpath_build_env)
+    {
+      kpath_build_env = kpath_env;
+    }
+    return std::make_tuple(kpath_env, kpath_build_env);
+  }
 
   std::string kdir = std::string("/lib/modules/") + utsname.release;
   auto ksrc = kdir + "/source";

diff --git a/tests/codegen/llvm/builtin_ctx_field.ll b/tests/codegen/llvm/builtin_ctx_field.ll
@@ -85,14 +85,14 @@ entry:
   call void @llvm.lifetime.start.p0i8(i64 -1, i8* %"struct c.c")
   %probe_read_kernel = call i64 inttoptr (i64 113 to i64 (i8*, i32, i64)*)(i8* %"struct c.c", i32 1, i64 %35)
   %36 = load i8, i8* %"struct c.c", align 1
-  %37 = sext i8 %36 to i64
   call void @llvm.lifetime.end.p0i8(i64 -1, i8* %"struct c.c")
-  %38 = bitcast i64* %"@d_key" to i8*
-  call void @llvm.lifetime.start.p0i8(i64 -1, i8* %38)
+  %37 = bitcast i64* %"@d_key" to i8*
+  call void @llvm.lifetime.start.p0i8(i64 -1, i8* %37)
   store i64 0, i64* %"@d_key", align 8
+  %38 = sext i8 %36 to i64
   %39 = bitcast i64* %"@d_val" to i8*
   call void @llvm.lifetime.start.p0i8(i64 -1, i8* %39)
-  store i64 %37, i64* %"@d_val", align 8
+  store i64 %38, i64* %"@d_val", align 8
   %pseudo5 = call i64 @llvm.bpf.pseudo(i64 1, i64 3)
   %update_elem6 = call i64 inttoptr (i64 2 to i64 (i64, i64*, i64*, i64)*)(i64 %pseudo5, i64* %"@d_key", i64* %"@d_val", i64 0)
   %40 = bitcast i64* %"@d_val" to i8*

diff --git a/tests/codegen/llvm/call_printf.ll b/tests/codegen/llvm/call_printf.ll
@@ -32,10 +32,10 @@ entry:
   call void @llvm.lifetime.start.p0i8(i64 -1, i8* %"struct Foo.c")
   %probe_read_kernel = call i64 inttoptr (i64 113 to i64 (i8*, i32, i64)*)(i8* %"struct Foo.c", i32 1, i64 %8)
   %9 = load i8, i8* %"struct Foo.c", align 1
-  %10 = sext i8 %9 to i64
   call void @llvm.lifetime.end.p0i8(i64 -1, i8* %"struct Foo.c")
-  %11 = getelementptr %printf_t, %printf_t* %printf_args, i32 0, i32 1
-  store i64 %10, i64* %11, align 8
+  %10 = getelementptr %printf_t, %printf_t* %printf_args, i32 0, i32 1
+  %11 = sext i8 %9 to i64
+  store i64 %11, i64* %10, align 8
   %12 = load i64, i64* %"$foo", align 8
   %13 = add i64 %12, 8
   %14 = bitcast i64* %"struct Foo.l" to i8*

diff --git a/tests/codegen/llvm/logical_and_or_different_type.ll b/tests/codegen/llvm/logical_and_or_different_type.ll
@@ -41,10 +41,9 @@ entry:
   call void @llvm.lifetime.start.p0i8(i64 -1, i8* %10)
   %probe_read_user = call i64 inttoptr (i64 112 to i64 (i32*, i32, i64)*)(i32* %"struct Foo.m", i32 4, i64 %9)
   %11 = load i32, i32* %"struct Foo.m", align 4
-  %12 = sext i32 %11 to i64
-  %13 = bitcast i32* %"struct Foo.m" to i8*
-  call void @llvm.lifetime.end.p0i8(i64 -1, i8* %13)
-  %lhs_true_cond = icmp ne i64 %12, 0
+  %12 = bitcast i32* %"struct Foo.m" to i8*
+  call void @llvm.lifetime.end.p0i8(i64 -1, i8* %12)
+  %lhs_true_cond = icmp ne i32 %11, 0
   br i1 %lhs_true_cond, label %"&&_lhs_true", label %"&&_false"
 
 "&&_lhs_true":                                    ; preds = %entry
@@ -59,24 +58,23 @@ entry:
   br label %"&&_merge"
 
 "&&_merge":                                       ; preds = %"&&_false", %"&&_true"
-  %14 = load i64, i64* %"&&_result", align 8
-  %15 = getelementptr %printf_t, %printf_t* %printf_args, i32 0, i32 1
-  store i64 %14, i64* %15, align 8
-  %16 = bitcast i64* %"&&_result5" to i8*
-  call void @llvm.lifetime.start.p0i8(i64 -1, i8* %16)
+  %13 = load i64, i64* %"&&_result", align 8
+  %14 = getelementptr %printf_t, %printf_t* %printf_args, i32 0, i32 1
+  store i64 %13, i64* %14, align 8
+  %15 = bitcast i64* %"&&_result5" to i8*
+  call void @llvm.lifetime.start.p0i8(i64 -1, i8* %15)
   br i1 true, label %"&&_lhs_true1", label %"&&_false3"
 
 "&&_lhs_true1":                                   ; preds = %"&&_merge"
-  %17 = load i64, i64* %"$foo", align 8
-  %18 = add i64 %17, 0
-  %19 = bitcast i32* %"struct Foo.m6" to i8*
-  call void @llvm.lifetime.start.p0i8(i64 -1, i8* %19)
-  %probe_read_user7 = call i64 inttoptr (i64 112 to i64 (i32*, i32, i64)*)(i32* %"struct Foo.m6", i32 4, i64 %18)
-  %20 = load i32, i32* %"struct Foo.m6", align 4
-  %21 = sext i32 %20 to i64
-  %22 = bitcast i32* %"struct Foo.m6" to i8*
-  call void @llvm.lifetime.end.p0i8(i64 -1, i8* %22)
-  %rhs_true_cond = icmp ne i64 %21, 0
+  %16 = load i64, i64* %"$foo", align 8
+  %17 = add i64 %16, 0
+  %18 = bitcast i32* %"struct Foo.m6" to i8*
+  call void @llvm.lifetime.start.p0i8(i64 -1, i8* %18)
+  %probe_read_user7 = call i64 inttoptr (i64 112 to i64 (i32*, i32, i64)*)(i32* %"struct Foo.m6", i32 4, i64 %17)
+  %19 = load i32, i32* %"struct Foo.m6", align 4
+  %20 = bitcast i32* %"struct Foo.m6" to i8*
+  call void @llvm.lifetime.end.p0i8(i64 -1, i8* %20)
+  %rhs_true_cond = icmp ne i32 %19, 0
   br i1 %rhs_true_cond, label %"&&_true2", label %"&&_false3"
 
 "&&_true2":                                       ; preds = %"&&_lhs_true1"
@@ -88,21 +86,20 @@ entry:
   br label %"&&_merge4"
 
 "&&_merge4":                                      ; preds = %"&&_false3", %"&&_true2"
-  %23 = load i64, i64* %"&&_result5", align 8
-  %24 = getelementptr %printf_t, %printf_t* %printf_args, i32 0, i32 2
-  store i64 %23, i64* %24, align 8
-  %25 = bitcast i64* %"||_result" to i8*
-  call void @llvm.lifetime.start.p0i8(i64 -1, i8* %25)
-  %26 = load i64, i64* %"$foo", align 8
-  %27 = add i64 %26, 0
+  %21 = load i64, i64* %"&&_result5", align 8
+  %22 = getelementptr %printf_t, %printf_t* %printf_args, i32 0, i32 2
+  store i64 %21, i64* %22, align 8
+  %23 = bitcast i64* %"||_result" to i8*
+  call void @llvm.lifetime.start.p0i8(i64 -1, i8* %23)
+  %24 = load i64, i64* %"$foo", align 8
+  %25 = add i64 %24, 0
+  %26 = bitcast i32* %"struct Foo.m8" to i8*
+  call void @llvm.lifetime.start.p0i8(i64 -1, i8* %26)
+  %probe_read_user9 = call i64 inttoptr (i64 112 to i64 (i32*, i32, i64)*)(i32* %"struct Foo.m8", i32 4, i64 %25)
+  %27 = load i32, i32* %"struct Foo.m8", align 4
   %28 = bitcast i32* %"struct Foo.m8" to i8*
-  call void @llvm.lifetime.start.p0i8(i64 -1, i8* %28)
-  %probe_read_user9 = call i64 inttoptr (i64 112 to i64 (i32*, i32, i64)*)(i32* %"struct Foo.m8", i32 4, i64 %27)
-  %29 = load i32, i32* %"struct Foo.m8", align 4
-  %30 = sext i32 %29 to i64
-  %31 = bitcast i32* %"struct Foo.m8" to i8*
-  call void @llvm.lifetime.end.p0i8(i64 -1, i8* %31)
-  %lhs_true_cond10 = icmp ne i64 %30, 0
+  call void @llvm.lifetime.end.p0i8(i64 -1, i8* %28)
+  %lhs_true_cond10 = icmp ne i32 %27, 0
   br i1 %lhs_true_cond10, label %"||_true", label %"||_lhs_false"
 
 "||_lhs_false":                                   ; preds = %"&&_merge4"
@@ -117,24 +114,23 @@ entry:
   br label %"||_merge"
 
 "||_merge":                                       ; preds = %"||_true", %"||_false"
-  %32 = load i64, i64* %"||_result", align 8
-  %33 = getelementptr %printf_t, %printf_t* %printf_args, i32 0, i32 3
-  store i64 %32, i64* %33, align 8
-  %34 = bitcast i64* %"||_result15" to i8*
-  call void @llvm.lifetime.start.p0i8(i64 -1, i8* %34)
+  %29 = load i64, i64* %"||_result", align 8
+  %30 = getelementptr %printf_t, %printf_t* %printf_args, i32 0, i32 3
+  store i64 %29, i64* %30, align 8
+  %31 = bitcast i64* %"||_result15" to i8*
+  call void @llvm.lifetime.start.p0i8(i64 -1, i8* %31)
   br i1 false, label %"||_true13", label %"||_lhs_false11"
 
 "||_lhs_false11":                                 ; preds = %"||_merge"
-  %35 = load i64, i64* %"$foo", align 8
-  %36 = add i64 %35, 0
-  %37 = bitcast i32* %"struct Foo.m16" to i8*
-  call void @llvm.lifetime.start.p0i8(i64 -1, i8* %37)
-  %probe_read_user17 = call i64 inttoptr (i64 112 to i64 (i32*, i32, i64)*)(i32* %"struct Foo.m16", i32 4, i64 %36)
-  %38 = load i32, i32* %"struct Foo.m16", align 4
-  %39 = sext i32 %38 to i64
-  %40 = bitcast i32* %"struct Foo.m16" to i8*
-  call void @llvm.lifetime.end.p0i8(i64 -1, i8* %40)
-  %rhs_true_cond18 = icmp ne i64 %39, 0
+  %32 = load i64, i64* %"$foo", align 8
+  %33 = add i64 %32, 0
+  %34 = bitcast i32* %"struct Foo.m16" to i8*
+  call void @llvm.lifetime.start.p0i8(i64 -1, i8* %34)
+  %probe_read_user17 = call i64 inttoptr (i64 112 to i64 (i32*, i32, i64)*)(i32* %"struct Foo.m16", i32 4, i64 %33)
+  %35 = load i32, i32* %"struct Foo.m16", align 4
+  %36 = bitcast i32* %"struct Foo.m16" to i8*
+  call void @llvm.lifetime.end.p0i8(i64 -1, i8* %36)
+  %rhs_true_cond18 = icmp ne i32 %35, 0
   br i1 %rhs_true_cond18, label %"||_true13", label %"||_false12"
 
 "||_false12":                                     ; preds = %"||_lhs_false11"
@@ -146,13 +142,13 @@ entry:
   br label %"||_merge14"
 
 "||_merge14":                                     ; preds = %"||_true13", %"||_false12"
-  %41 = load i64, i64* %"||_result15", align 8
-  %42 = getelementptr %printf_t, %printf_t* %printf_args, i32 0, i32 4
-  store i64 %41, i64* %42, align 8
+  %37 = load i64, i64* %"||_result15", align 8
+  %38 = getelementptr %printf_t, %printf_t* %printf_args, i32 0, i32 4
+  store i64 %37, i64* %38, align 8
   %pseudo = call i64 @llvm.bpf.pseudo(i64 1, i64 0)
   %perf_event_output = call i64 inttoptr (i64 25 to i64 (i8*, i64, i64, %printf_t*, i64)*)(i8* %0, i64 %pseudo, i64 4294967295, %printf_t* %printf_args, i64 40)
-  %43 = bitcast %printf_t* %printf_args to i8*
-  call void @llvm.lifetime.end.p0i8(i64 -1, i8* %43)
+  %39 = bitcast %printf_t* %printf_args to i8*
+  call void @llvm.lifetime.end.p0i8(i64 -1, i8* %39)
   ret i64 0
 }