added addr_to_symbol function

6 files changed, 112 insertions, 0 deletions

diff --git a/eval/CMakeLists.txt b/eval/CMakeLists.txt
index 4af337dcb67..4b2127d8a3a 100644
--- a/eval/CMakeLists.txt
+++ b/eval/CMakeLists.txt
@@ -12,6 +12,7 @@ vespa_define_module(
 
     TESTS
     src/tests/ann
+    src/tests/eval/addr_to_symbol
     src/tests/eval/aggr
     src/tests/eval/array_array_map
     src/tests/eval/cell_type_space
diff --git a/eval/src/tests/eval/addr_to_symbol/CMakeLists.txt b/eval/src/tests/eval/addr_to_symbol/CMakeLists.txt
new file mode 100644
index 00000000000..eddace54cfe
--- /dev/null
+++ b/eval/src/tests/eval/addr_to_symbol/CMakeLists.txt
@@ -0,0 +1,9 @@
+# Copyright Verizon Media. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+vespa_add_executable(eval_addr_to_symbol_test_app TEST
+    SOURCES
+    addr_to_symbol_test.cpp
+    DEPENDS
+    vespaeval
+    GTest::GTest
+)
+vespa_add_test(NAME eval_addr_to_symbol_test_app COMMAND eval_addr_to_symbol_test_app)
diff --git a/eval/src/tests/eval/addr_to_symbol/addr_to_symbol_test.cpp b/eval/src/tests/eval/addr_to_symbol/addr_to_symbol_test.cpp
new file mode 100644
index 00000000000..fade4bf961f
--- /dev/null
+++ b/eval/src/tests/eval/addr_to_symbol/addr_to_symbol_test.cpp
@@ -0,0 +1,25 @@
+// Copyright Verizon Media. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+
+#include <vespa/eval/eval/llvm/addr_to_symbol.h>
+#include <vespa/vespalib/gtest/gtest.h>
+
+using namespace vespalib::eval;
+
+TEST(AddrToSymbol, null_ptr) {
+    auto sym = addr_to_symbol(nullptr);
+    EXPECT_EQ(sym, "<nullptr>");
+}
+
+TEST(AddrToSymbol, global_symbol) {
+    auto sym = addr_to_symbol((const void *)addr_to_symbol);
+    fprintf(stderr, "global symbol: %s\n", sym.c_str());
+    EXPECT_TRUE(sym.find("addr_to_symbol") < sym.size());
+}
+
+TEST(AddrToSymbol, local_symbol) {
+    auto sym = addr_to_symbol(get_addr_of_local_test_symbol());
+    fprintf(stderr, "local symbol: %s\n", sym.c_str());
+    EXPECT_TRUE(sym.find("my_local_test_symbol") < sym.size());
+}
+
+GTEST_MAIN_RUN_ALL_TESTS()
diff --git a/eval/src/vespa/eval/eval/llvm/CMakeLists.txt b/eval/src/vespa/eval/eval/llvm/CMakeLists.txt
index 898d18c9e4c..a3ca410842a 100644
--- a/eval/src/vespa/eval/eval/llvm/CMakeLists.txt
+++ b/eval/src/vespa/eval/eval/llvm/CMakeLists.txt
@@ -1,6 +1,7 @@
 # Copyright 2017 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
 vespa_add_library(eval_eval_llvm OBJECT
     SOURCES
+    addr_to_symbol.cpp
     compile_cache.cpp
     compiled_function.cpp
     deinline_forest.cpp
diff --git a/eval/src/vespa/eval/eval/llvm/addr_to_symbol.cpp b/eval/src/vespa/eval/eval/llvm/addr_to_symbol.cpp
new file mode 100644
index 00000000000..566ab931837
--- /dev/null
+++ b/eval/src/vespa/eval/eval/llvm/addr_to_symbol.cpp
@@ -0,0 +1,57 @@
+// Copyright Verizon Media. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+
+#include "addr_to_symbol.h"
+#include <vespa/vespalib/util/classname.h>
+
+#include <dlfcn.h>
+#include <llvm/Object/ObjectFile.h>
+
+using vespalib::demangle;
+using llvm::object::ObjectFile;
+
+namespace vespalib::eval {
+
+namespace {
+
+void my_local_test_symbol() {}
+
+} // <unnamed>
+
+vespalib::string addr_to_symbol(const void *addr) {
+    if (addr == nullptr) {
+        return {"<nullptr>"};
+    }
+    Dl_info info;
+    memset(&info, 0, sizeof(info));
+    if (dladdr(addr, &info) == 0) {
+        // address not in any shared object
+        return {"<invalid>"};
+    }
+    if (info.dli_sname != nullptr) {
+        // address of global symbol
+        return demangle(info.dli_sname);
+    }
+    // find addr offset into shared object
+    uint64_t offset = ((const char *)addr) - ((const char *)info.dli_fbase);
+    // use llvm to look up local symbols...
+    auto file = ObjectFile::createObjectFile(info.dli_fname);
+    if (!file) {
+        return {"<object_error>"};
+    }
+    auto symbols = file.get().getBinary()->symbols();
+    for (const auto &symbol: symbols) {
+        auto sym_name = symbol.getName();
+        auto sym_addr = symbol.getAddress();
+        if (sym_name && sym_addr && (*sym_addr == offset)) {
+            return demangle(sym_name->str().c_str());
+        }
+    }
+    // could not resolve symbol
+    return {"<unknown>"};
+}
+
+const void *get_addr_of_local_test_symbol() {
+    return (const void *) my_local_test_symbol;
+}
+
+}
diff --git a/eval/src/vespa/eval/eval/llvm/addr_to_symbol.h b/eval/src/vespa/eval/eval/llvm/addr_to_symbol.h
new file mode 100644
index 00000000000..29c83be7260
--- /dev/null
+++ b/eval/src/vespa/eval/eval/llvm/addr_to_symbol.h
@@ -0,0 +1,19 @@
+// Copyright Verizon Media. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
+
+#pragma once
+
+#include <vespa/vespalib/stllike/string.h>
+
+namespace vespalib::eval {
+
+// Map an address to a symbolic name.
+// Intended for function pointers.
+
+vespalib::string addr_to_symbol(const void *addr);
+
+// Return the address of a local symbol.
+// Used for testing.
+
+const void *get_addr_of_local_test_symbol();
+
+}