Support call stacks on Windows

.github/workflows/win.yml

@@ -172,7 +172,7 @@ jobs:
           cl /MT /c src\llvm\ext\llvm_ext.cc -I llvm\include /Fosrc\llvm\ext\llvm_ext.obj
       - name: Link Crystal executable
         run: |
-          Invoke-Expression "cl crystal.obj /Fecrystal-cross src\llvm\ext\llvm_ext.obj $(llvm\bin\llvm-config.exe --libs) libs\pcre.lib libs\gc.lib WS2_32.lib advapi32.lib libcmt.lib legacy_stdio_definitions.lib /F10000000"
+          Invoke-Expression "cl crystal.obj /Fecrystal-cross src\llvm\ext\llvm_ext.obj $(llvm\bin\llvm-config.exe --libs) libs\pcre.lib libs\gc.lib WS2_32.lib advapi32.lib libcmt.lib dbghelp.lib legacy_stdio_definitions.lib /F10000000"
 
       - name: Re-build Crystal
         run: |

spec/std/exception/call_stack_spec.cr

@@ -1,7 +1,7 @@
 require "../spec_helper"
 
 describe "Backtrace" do
-  pending_win32 "prints file line:column" do
+  it "prints file line:column" do
     source_file = datapath("backtrace_sample")
 
     # CallStack tries to make files relative to the current dir,
@@ -12,17 +12,23 @@ describe "Backtrace" do
 
     _, output, _ = compile_and_run_file(source_file)
 
-    # resolved file line:column
-    output.should match(/^#{source_file}:3:10 in 'callee1'/m)
-    output.should match(/^#{source_file}:13:5 in 'callee3'/m)
+    # resolved file:line:column (no column for windows PDB because of poor
+    # support in general)
+    {% if flag?(:win32) %}
+      output.should match(/^#{Regex.escape(source_file)}:3 in 'callee1'/m)
+      output.should match(/^#{Regex.escape(source_file)}:13 in 'callee3'/m)
+    {% else %}
+      output.should match(/^#{Regex.escape(source_file)}:3:10 in 'callee1'/m)
+      output.should match(/^#{Regex.escape(source_file)}:13:5 in 'callee3'/m)
+    {% end %}
 
     # skipped internal details
     output.should_not contain("src/callstack.cr")
     output.should_not contain("src/exception.cr")
     output.should_not contain("src/raise.cr")
   end
 
-  pending_win32 "doesn't relativize paths outside of current dir (#10169)" do
+  it "doesn't relativize paths outside of current dir (#10169)" do
     with_tempfile("source_file") do |source_file|
       source_path = Path.new(source_file)
       source_path.absolute?.should be_true
@@ -36,7 +42,7 @@ describe "Backtrace" do
         EOF
       _, output, _ = compile_and_run_file(source_file)
 
-      output.should match /\A(#{source_path}):/
+      output.should match /\A(#{Regex.escape(source_path.to_s)}):/
     end
   end
 

spec/std/raise_spec.cr

@@ -3,14 +3,14 @@ require "./spec_helper"
 describe "raise" do
   callstack_on_rescue = nil
 
-  pending_win32 "should set exception's callstack" do
+  it "should set exception's callstack" do
     exception = expect_raises Exception, "without callstack" do
       raise "without callstack"
     end
     exception.callstack.should_not be_nil
   end
 
-  pending_win32 "shouldn't overwrite the callstack on re-raise" do
+  it "shouldn't overwrite the callstack on re-raise" do
     exception_after_reraise = expect_raises Exception, "exception to be rescued" do
       begin
         raise "exception to be rescued"

src/compiler/crystal/codegen/codegen.cr

@@ -28,6 +28,8 @@ module Crystal
 
     def evaluate(node, debug = Debug::Default)
       llvm_mod = codegen(node, single_module: true, debug: debug)[""].mod
+      llvm_mod.target = target_machine.triple
+
       main = llvm_mod.functions[MAIN_NAME]
 
       main_return_type = main.return_type

src/compiler/crystal/codegen/debug.cr

@@ -33,9 +33,16 @@ module Crystal
     def push_debug_info_metadata(mod)
       di_builder(mod).end
 
-      # DebugInfo generation in LLVM by default uses a higher version of dwarf
-      # than OS X currently understands. Android has the same problem.
-      if @program.has_flag?("osx") || @program.has_flag?("android")
+      if @program.has_flag?("windows")
+        # Windows uses CodeView instead of DWARF
+        mod.add_flag(
+          LLVM::ModuleFlag::Warning,
+          "CodeView",
+          mod.context.int32.const_int(1)
+        )
+      elsif @program.has_flag?("osx") || @program.has_flag?("android")
+        # DebugInfo generation in LLVM by default uses a higher version of dwarf
+        # than OS X currently understands. Android has the same problem.
         mod.add_flag(
           LLVM::ModuleFlag::Warning,
           "Dwarf Version",

src/compiler/crystal/compiler.cr

@@ -346,7 +346,7 @@ module Crystal
         object_arg = Process.quote_windows(object_names)
         output_arg = Process.quote_windows("/Fe#{output_filename}")
 
-        args = %(/nologo #{object_arg} #{output_arg} /link #{lib_flags} #{@link_flags}).gsub("\n", " ")
+        args = %(/nologo #{object_arg} #{output_arg} /link#{" /DEBUG:FULL" unless debug.none?} #{lib_flags} #{@link_flags}).gsub("\n", " ")
         cmd = "#{CL} #{args}"
 
         if cmd.to_utf16.size > 32000

src/exception.cr

@@ -35,11 +35,7 @@ class Exception
   # The backtrace is an array of strings, each containing
   # “0xAddress: Function at File Line Column”.
   def backtrace?
-    {% if flag?(:win32) %}
-      Array(String).new
-    {% else %}
-      @callstack.try &.printable_backtrace
-    {% end %}
+    @callstack.try &.printable_backtrace
   end
 
   def to_s(io : IO) : Nil

src/exception/call_stack.cr

@@ -1,6 +1,8 @@
-{% skip_file if flag?(:win32) %}
-
-require "./call_stack/libunwind"
+{% if flag?(:win32) %}
+  require "./call_stack/stackwalk"
+{% else %}
+  require "./call_stack/libunwind"
+{% end %}
 
 # Returns the current execution stack as an array containing strings
 # usually in the form file:line:column or file:line:column in 'method'.
@@ -12,12 +14,7 @@ end
 struct Exception::CallStack
   # Compute current directory at the beginning so filenames
   # are always shown relative to the *starting* working directory.
-  CURRENT_DIR = begin
-    if dir = Process::INITIAL_PWD
-      dir += File::SEPARATOR unless dir.ends_with?(File::SEPARATOR)
-      dir
-    end
-  end
+  private CURRENT_DIR = Process::INITIAL_PWD.try { |dir| Path[dir] }
 
   @@skip = [] of String
 
@@ -37,4 +34,64 @@ struct Exception::CallStack
   def printable_backtrace : Array(String)
     @backtrace ||= decode_backtrace
   end
+
+  private def decode_backtrace
+    show_full_info = ENV["CRYSTAL_CALLSTACK_FULL_INFO"]? == "1"
+
+    @callstack.compact_map do |ip|
+      pc = CallStack.decode_address(ip)
+
+      file, line_number, column_number = CallStack.decode_line_number(pc)
+
+      if file && file != "??"
+        next if @@skip.includes?(file)
+
+        # Turn to relative to the current dir, if possible
+        if current_dir = CURRENT_DIR
+          if rel = Path[file].relative_to?(current_dir)
+            rel = rel.to_s
+            file = rel unless rel.starts_with?("..")
+          end
+        end
+
+        file_line_column = file
+        unless line_number == 0
+          file_line_column = "#{file_line_column}:#{line_number}"
+          file_line_column = "#{file_line_column}:#{column_number}" unless column_number == 0
+        end
+      end
+
+      if name = CallStack.decode_function_name(pc)
+        function = name
+      elsif frame = CallStack.decode_frame(ip)
+        _, function, file = frame
+        # Crystal methods (their mangled name) start with `*`, so
+        # we remove that to have less clutter in the output.
+        function = function.lchop('*')
+      else
+        function = "??"
+      end
+
+      if file_line_column
+        if show_full_info && (frame = CallStack.decode_frame(ip))
+          _, sname, _ = frame
+          line = "#{file_line_column} in '#{sname}'"
+        else
+          line = "#{file_line_column} in '#{function}'"
+        end
+      else
+        if file == "??" && function == "??"
+          line = "???"
+        else
+          line = "#{file} in '#{function}'"
+        end
+      end
+
+      if show_full_info
+        line = "#{line} at 0x#{ip.address.to_s(16)}"
+      end
+
+      line
+    end
+  end
 end

src/exception/call_stack/dwarf.cr

@@ -11,12 +11,13 @@ struct Exception::CallStack
   @@dwarf_function_names : Array(Tuple(LibC::SizeT, LibC::SizeT, String))?
 
   # :nodoc:
-  def self.load_dwarf
+  def self.load_debug_info
+    return if ENV["CRYSTAL_LOAD_DEBUG_INFO"]? == "0"
+
     unless @@dwarf_loaded
       @@dwarf_loaded = true
       begin
-        return if ENV["CRYSTAL_LOAD_DWARF"]? == "0"
-        load_dwarf_impl
+        load_debug_info_impl
       rescue ex
         @@dwarf_line_numbers = nil
         @@dwarf_function_names = nil
@@ -26,7 +27,7 @@ struct Exception::CallStack
   end
 
   protected def self.decode_line_number(pc)
-    load_dwarf
+    load_debug_info
     if ln = @@dwarf_line_numbers
       if row = ln.find(pc)
         return {row.path, row.line, row.column}
@@ -36,7 +37,7 @@ struct Exception::CallStack
   end
 
   protected def self.decode_function_name(pc)
-    load_dwarf
+    load_debug_info
     if fn = @@dwarf_function_names
       fn.each do |(low_pc, high_pc, function_name)|
         return function_name if low_pc <= pc <= high_pc

src/exception/call_stack/elf.cr

@@ -2,7 +2,7 @@ require "crystal/elf"
 require "c/link"
 
 struct Exception::CallStack
-  protected def self.load_dwarf_impl
+  protected def self.load_debug_info_impl
     phdr_callback = LibC::DlPhdrCallback.new do |info, size, data|
       # The first entry is the header for the current program
       read_dwarf_sections(info.value.addr)

src/exception/call_stack/libunwind.cr

@@ -129,59 +129,6 @@ struct Exception::CallStack
     end
   end
 
-  private def decode_backtrace
-    show_full_info = ENV["CRYSTAL_CALLSTACK_FULL_INFO"]? == "1"
-
-    @callstack.compact_map do |ip|
-      pc = CallStack.decode_address(ip)
-
-      file, line, column = CallStack.decode_line_number(pc)
-
-      if file && file != "??"
-        next if @@skip.includes?(file)
-
-        # Turn to relative to the current dir, if possible
-        if current_dir = CURRENT_DIR
-          file = file.lchop(current_dir)
-        end
-
-        file_line_column = "#{file}:#{line}:#{column}"
-      end
-
-      if name = CallStack.decode_function_name(pc)
-        function = name
-      elsif frame = CallStack.decode_frame(ip)
-        _, function, file = frame
-        # Crystal methods (their mangled name) start with `*`, so
-        # we remove that to have less clutter in the output.
-        function = function.lchop('*')
-      else
-        function = "??"
-      end
-
-      if file_line_column
-        if show_full_info && (frame = CallStack.decode_frame(ip))
-          _, sname, _ = frame
-          line = "#{file_line_column} in '#{sname}'"
-        else
-          line = "#{file_line_column} in '#{function}'"
-        end
-      else
-        if file == "??" && function == "??"
-          line = "???"
-        else
-          line = "#{file} in '#{function}'"
-        end
-      end
-
-      if show_full_info
-        line = "#{line} at 0x#{ip.address.to_s(16)}"
-      end
-
-      line
-    end
-  end
-
   protected def self.decode_frame(ip, original_ip = ip)
     if LibC.dladdr(ip, out info) != 0
       offset = original_ip - info.dli_saddr

src/exception/call_stack/mach_o.cr

@@ -9,7 +9,7 @@ end
 struct Exception::CallStack
   @@image_slide : LibC::Long?
 
-  protected def self.load_dwarf_impl
+  protected def self.load_debug_info_impl
     read_dwarf_sections
   end