Set compiler for OSRM build

[kkarbowiak]

Issue #1098

Tasks

• Update CHANGELOG.md (remove if irrelevant)
• review

[kkarbowiak]

While current master branch compiles fine using clang-15 on my machine, the v5.27.1 release sadly does not. I guess I forgot about the compilation problems with this project.

[kkarbowiak]

Compilation with g++-12 fails for both v5.27.1 and current master.

[jcoupey]

Building OSRM with g++-12 works on v5.27.1 when adding -DCMAKE_CXX_FLAGS="-Wno-array-bounds -Wno-uninitialized" to the first cmake .. command. There are a couple issues related to the error without those flags on the OSRM bugtracker. Long story short this is how it's done on the OSRM CI pipeline for gcc-12.

I'll try to investigate the clang-15 errors since we'll have to sort them out in some way if we ever want #1080 to happen before another upstream release.

[jcoupey]

The clang++-15 errors are fairly simple and have been fixed upstream in master in various commits. Porting the changes back to v5.27.1 boils down to applying this patch:

diff --git a/include/util/range_table.hpp b/include/util/range_table.hpp
index aa1b89f1c..31379ada6 100644
--- a/include/util/range_table.hpp
+++ b/include/util/range_table.hpp
@@ -81,10 +81,10 @@ template <unsigned BLOCK_SIZE, storage::Ownership Ownership> class RangeTable
         unsigned last_length = 0;
         unsigned lengths_prefix_sum = 0;
         unsigned block_idx = 0;
-        unsigned block_counter = 0;
         BlockT block;
 #ifndef BOOST_ASSERT_IS_VOID
         unsigned block_sum = 0;
+        unsigned block_counter = 0;
 #endif
         for (const unsigned l : lengths)
         {
@@ -111,7 +111,9 @@ template <unsigned BLOCK_SIZE, storage::Ownership Ownership> class RangeTable
             if (BLOCK_SIZE == block_idx)
             {
                 diff_blocks.push_back(block);
+#ifndef BOOST_ASSERT_IS_VOID
                 block_counter++;
+#endif
             }
 
             // we can only store strings with length 255
diff --git a/src/contractor/graph_contractor.cpp b/src/contractor/graph_contractor.cpp
index 0b3e87cc2..17a386f11 100644
--- a/src/contractor/graph_contractor.cpp
+++ b/src/contractor/graph_contractor.cpp
@@ -645,7 +645,6 @@ std::vector<bool> contractGraph(ContractorGraph &graph,
 
     const util::XORFastHash<> hash;
 
-    unsigned current_level = 0;
     std::size_t next_renumbering = number_of_nodes * 0.35;
     while (remaining_nodes.size() > number_of_core_nodes)
     {
@@ -761,7 +760,6 @@ std::vector<bool> contractGraph(ContractorGraph &graph,
         remaining_nodes.resize(begin_independent_nodes_idx);
 
         p.PrintStatus(number_of_contracted_nodes);
-        ++current_level;
     }
 
     node_data.Renumber(new_to_old_node_id);

Unfortunately the two commits containing those changes also contain other changes in other files (or the same files) so that it is no possible to simply cherry-pick just the above on top of v5.27.1.

What about storing this patch somewhere in our include folder and applying in CI? I'm aware this would only be a temporary workaround, but as far as OSRM releases are concerned a temporary workaround may be here to stay...

[jcoupey]

Closing here as the scope of this PR has been addressed as part of #1113. Thanks @kkarbowiak for the include tip for additional variables in the worfklow.