C#: Add experimental lua-based tracing config.

csharp/tools/tracing-config.lua

@@ -0,0 +1,80 @@
+function RegisterExtractorPack()
+    local extractorDirectory = "tools" .. PathSep .. PlatformDirectory ..
+                                   PathSep
+    local csharpExtractor = extractorDirectory ..
+                                'Semmle.Extraction.CSharp.Driver'
+    if OperatingSystem == 'windows' then
+        csharpExtractor = extractorDirectory ..
+                              'Semmle.Extraction.CSharp.Driver.exe'
+    end
+
+    -- TODO Windows support for the entire file
+    -- everything here is very experimental and only a proof of concept
+    function DotnetMatcherBuild(compilerName, compilerPath, argv)
+        if compilerName ~= 'dotnet' then return nil end
+
+        -- this is probably too simplistic, but works for now
+        local match = false
+        for _, arg in ipairs(argv) do
+            if arg == 'build' then
+                match = true
+                break
+            end
+        end
+        if match then
+            table.insert(argv, '/p:UseSharedCompilation=false')
+            return {
+                trace = true,
+                replace = true,
+                invocations = {{path = compilerPath, argv = argv}}
+            }
+        else
+            return nil
+        end
+    end
+
+    function DotnetMatcherExec(compilerName, compilerPath, argv)
+        if compilerName ~= 'dotnet' then return nil end
+        -- TODO on windows this doesn't split argv correctly
+        local match = false
+        local newArgv = {'--compiler'}
+        for i, arg in ipairs(argv) do
+            -- TODO check if this is the correct regex, or if it should be more specific (and escape the dots!)
+            if arg:match('csc.exe') or arg:match('mcs.exe') or
+                arg:match('csc.dll') then
+                match = true
+                -- newArgv contains all elements of argv from i+1 to the end
+                table.insert(newArgv, arg)
+                table.insert(newArgv, '--cil')
+                for j = i + 1, #argv do
+                    table.insert(newArgv, argv[j])
+                end
+                break
+            end
+        end
+        if match then
+            return {
+                trace = true,
+                replace = false,
+                invocations = {
+                    {
+                        path = GetExtractorPath('csharp', csharpExtractor),
+                        argv = newArgv
+                    }
+                }
+            }
+        else
+            return nil
+        end
+    end
+
+    -- TODO windows matchers patterns
+    local matchers = {
+        CreatePatternMatcher('csharp', {'^mcs.exe$', '^csc.exe$'},
+                             MatchCompilerName, csharpExtractor,
+                             {prepend = {'--compiler', '${compiler}', '--cil'}}),
+        DotnetMatcherBuild, DotnetMatcherExec
+    }
+
+    RegisterLanguage('csharp', matchers)
+end