From ba41501bb2ca89312061b31c08e570a11c092370 Mon Sep 17 00:00:00 2001

From: mephi42 <mephi42@gmail.com>

Date: Tue, 12 Mar 2019 07:02:56 +0100

Subject: [PATCH] Add basic USDT support for s390x (#2266)

Approach and code shamelessly borrowed from "422db709: Add basic USDT

support for powerpc64".

---

 src/cc/usdt.h              |  7 +++++

 src/cc/usdt/usdt.cc        |  2 ++

 src/cc/usdt/usdt_args.cc   | 53 ++++++++++++++++++++++++++++++++++++++

 tests/cc/test_usdt_args.cc | 46 +++++++++++++++++++++++++++++++++

 4 files changed, 108 insertions(+)

diff --git a/src/cc/usdt.h b/src/cc/usdt.h

index 6d89fd644..406cfd546 100644

--- a/src/cc/usdt.h

+++ b/src/cc/usdt.h

@@ -81,6 +81,7 @@ class Argument {

   friend class ArgumentParser;

   friend class ArgumentParser_aarch64;

   friend class ArgumentParser_powerpc64;

+  friend class ArgumentParser_s390x;

   friend class ArgumentParser_x64;

 };

@@ -130,6 +131,12 @@ class ArgumentParser_powerpc64 : public ArgumentParser {

   ArgumentParser_powerpc64(const char *arg) : ArgumentParser(arg) {}

 };

+class ArgumentParser_s390x : public ArgumentParser {

+public:

+  bool parse(Argument *dest);

+  ArgumentParser_s390x(const char *arg) : ArgumentParser(arg) {}

+};

+

 class ArgumentParser_x64 : public ArgumentParser {

 private:

   enum Register {

diff --git a/src/cc/usdt/usdt.cc b/src/cc/usdt/usdt.cc

index 0914fe3a5..c91faa016 100644

--- a/src/cc/usdt/usdt.cc

+++ b/src/cc/usdt/usdt.cc

@@ -40,6 +40,8 @@ Location::Location(uint64_t addr, const std::string &bin_path, const char *arg_f

   ArgumentParser_aarch64 parser(arg_fmt);

 #elif __powerpc64__

   ArgumentParser_powerpc64 parser(arg_fmt);

+#elif __s390x__

+  ArgumentParser_s390x parser(arg_fmt);

 #else

   ArgumentParser_x64 parser(arg_fmt);

 #endif

diff --git a/src/cc/usdt/usdt_args.cc b/src/cc/usdt/usdt_args.cc

index b27e515f4..3e2045575 100644

--- a/src/cc/usdt/usdt_args.cc

+++ b/src/cc/usdt/usdt_args.cc

@@ -285,6 +285,59 @@ bool ArgumentParser_powerpc64::parse(Argument *dest) {

   return true;

 }

+bool ArgumentParser_s390x::parse(Argument *dest) {

+  if (done())

+    return false;

+

+  bool matched;

+  std::cmatch matches;

+#define S390X_IMM "(-?[0-9]+)"

+  std::regex arg_n_regex("^" S390X_IMM "@");

+  // <imm>

+  std::regex arg_op_regex_imm("^" S390X_IMM "(?: +|$)");

+  // %r<N>

+#define S390X_REG "%r([0-9]|1[0-5])"

+  std::regex arg_op_regex_reg("^" S390X_REG "(?: +|$)");

+  // <disp>(%r<N>,%r<N>)

+  std::regex arg_op_regex_mem("^" S390X_IMM "?\\(" S390X_REG

+                              "(?:," S390X_REG ")?\\)(?: +|$)");

+#undef S390X_IMM

+#undef S390X_REG

+

+  matched = std::regex_search(arg_ + cur_pos_, matches, arg_n_regex);

+  if (matched) {

+    dest->arg_size_ = stoi(matches.str(1));

+    cur_pos_ += matches.length(0);

+

+    if (std::regex_search(arg_ + cur_pos_, matches, arg_op_regex_imm)) {

+      dest->constant_ = stoi(matches.str(1));

+    } else if (std::regex_search(arg_ + cur_pos_, matches, arg_op_regex_reg)) {

+      dest->base_register_name_ = "gprs[" + matches.str(1) + "]";

+    } else if (std::regex_search(arg_ + cur_pos_, matches, arg_op_regex_mem)) {

+      if (matches.length(1) > 0) {

+        dest->deref_offset_ = stoi(matches.str(1));

+      }

+      dest->base_register_name_ = "gprs[" + matches.str(2) + "]";

+      if (matches.length(3) > 0) {

+        dest->index_register_name_ = "gprs[" + matches.str(3) + "]";

+      }

+    } else {

+      matched = false;

+    }

+  }

+

+  if (!matched) {

+    print_error(cur_pos_);

+    skip_until_whitespace_from(cur_pos_);

+    skip_whitespace_from(cur_pos_);

+    return false;

+  }

+

+  cur_pos_ += matches.length(0);

+  skip_whitespace_from(cur_pos_);

+  return true;

+}

+

 ssize_t ArgumentParser_x64::parse_identifier(ssize_t pos,

                                              optional<std::string> *result) {

   if (isalpha(arg_[pos]) || arg_[pos] == '_') {

diff --git a/tests/cc/test_usdt_args.cc b/tests/cc/test_usdt_args.cc

index 3a96c5aac..db1f8c8e6 100644

--- a/tests/cc/test_usdt_args.cc

+++ b/tests/cc/test_usdt_args.cc

@@ -58,6 +58,8 @@ TEST_CASE("test usdt argument parsing", "[usdt]") {

     USDT::ArgumentParser_aarch64 parser("4@[x32,200]");

 #elif __powerpc64__

     USDT::ArgumentParser_powerpc64 parser("4@-12(42)");

+#elif __s390x__

+    USDT::ArgumentParser_s390x parser("4@-12(%r42)");

 #elif defined(__x86_64__)

     USDT::ArgumentParser_x64 parser("4@i%ra+1r");

 #endif

@@ -121,6 +123,50 @@ TEST_CASE("test usdt argument parsing", "[usdt]") {

     verify_register(parser, 2, 1097);

     verify_register(parser, 4, "gpr[30]", 108);

     verify_register(parser, -2, "gpr[31]", -4);

+#elif __s390x__

+    USDT::ArgumentParser_s390x parser(

+        "-4@%r0 8@%r0 8@0 4@0(%r0) -2@0(%r0) "

+        "1@%r0 -2@%r3 -8@9 -1@0(%r4) -4@16(%r6) "

+        "2@%r7 4@%r11 4@-67 8@-16(%r15) 1@-52(%r11) "

+        "-8@%r4 -8@%r14 2@-11 -2@14(%r13) -8@-32(%r12) "

+        "4@%r5 2@%r11 -8@-693 -1@-23(%r10) 4@28(%r9) "

+        "-2@%r3 -4@%r8 2@1097 4@108(%r7) -2@-4(%r6)");

+

+    verify_register(parser, -4, "gprs[0]");

+    verify_register(parser, 8, "gprs[0]");

+    verify_register(parser, 8, 0);

+    verify_register(parser, 4, "gprs[0]", 0);

+    verify_register(parser, -2, "gprs[0]", 0);

+

+    verify_register(parser, 1, "gprs[0]");

+    verify_register(parser, -2, "gprs[3]");

+    verify_register(parser, -8, 9);

+    verify_register(parser, -1, "gprs[4]", 0);

+    verify_register(parser, -4, "gprs[6]", 16);

+

+    verify_register(parser, 2, "gprs[7]");

+    verify_register(parser, 4, "gprs[11]");

+    verify_register(parser, 4, -67);

+    verify_register(parser, 8, "gprs[15]", -16);

+    verify_register(parser, 1, "gprs[11]", -52);

+

+    verify_register(parser, -8, "gprs[4]");

+    verify_register(parser, -8, "gprs[14]");

+    verify_register(parser, 2, -11);

+    verify_register(parser, -2, "gprs[13]", 14);

+    verify_register(parser, -8, "gprs[12]", -32);

+

+    verify_register(parser, 4, "gprs[5]");

+    verify_register(parser, 2, "gprs[11]");

+    verify_register(parser, -8, -693);

+    verify_register(parser, -1, "gprs[10]", -23);

+    verify_register(parser, 4, "gprs[9]", 28);

+

+    verify_register(parser, -2, "gprs[3]");

+    verify_register(parser, -4, "gprs[8]");

+    verify_register(parser, 2, 1097);

+    verify_register(parser, 4, "gprs[7]", 108);

+    verify_register(parser, -2, "gprs[6]", -4);

 #elif defined(__x86_64__)

     USDT::ArgumentParser_x64 parser(

         "-4@$0 8@$1234 %rdi %rax %rsi "