Try #1050:

builder/comp-builder.nix

@@ -1,4 +1,4 @@
-{ pkgs, stdenv, buildPackages, ghc, lib, gobject-introspection ? null, haskellLib, makeConfigFiles, haddockBuilder, ghcForComponent, hsPkgs, compiler, runCommand, libffi, gmp, zlib, ncurses, numactl, nodejs }:
+{ pkgs, stdenv, buildPackages, ghc, lib, gobject-introspection ? null, haskellLib, makeConfigFiles, haddockBuilder, ghcForComponent, hsPkgs, compiler, runCommand, libffi, gmp, zlib, ncurses, numactl, nodejs }@defaults:
 lib.makeOverridable (
 let self =
 { componentId
@@ -77,6 +77,16 @@ let self =
 }@drvArgs:
 
 let
+  # Ignore attempts to include DWARF info when it is not possible
+  enableDWARF = drvArgs.enableDWARF or false
+    && stdenv.hostPlatform.isLinux
+    && !haskellLib.isCrossHost
+    && !stdenv.hostPlatform.isMusl
+    && builtins.compareVersions defaults.ghc.version "8.10.2" >= 0;
+
+  ghc = if enableDWARF then defaults.ghc.dwarf else defaults.ghc;
+  setup = if enableDWARF then drvArgs.setup.dwarf else drvArgs.setup;
+
   # TODO fix cabal wildcard support so hpack wildcards can be mapped to cabal wildcards
   canCleanSource = !(cabal-generator == "hpack" && !(package.cleanHpack or false));
   # In order to support relative references to other packages we need to use
@@ -109,7 +119,7 @@ let
 
   configFiles = makeConfigFiles {
     inherit (package) identifier;
-    inherit component fullName flags needsProfiling;
+    inherit component fullName flags needsProfiling enableDWARF;
   };
 
   enableFeature = enable: feature:
@@ -178,7 +188,7 @@ let
       ++ (ghc.extraConfigureFlags or [])
       ++ lib.optional enableDebugRTS "--ghc-option=-debug"
       ++ lib.optional enableTSanRTS "--ghc-option=-tsan"
-      ++ lib.optional enableDWARF "--ghc-option=-g"
+      ++ lib.optional enableDWARF "--ghc-option=-g3"
       ++ lib.optionals useLLVM [
         "--ghc-option=-fPIC" "--gcc-option=-fPIC"
         ]
@@ -195,7 +205,7 @@ let
   # work in the nix-shell. See ../doc/removing-with-package-wrapper.md.
   shellWrappers = ghcForComponent {
     componentName = fullName;
-    inherit configFiles;
+    inherit configFiles enableDWARF;
   };
 
   # In order to let shell hooks make package-specific things like Hoogle databases
@@ -280,10 +290,11 @@ let
       config = component;
       srcSubDir = cleanSrc.subDir;
       srcSubDirPath = cleanSrc.root + cleanSrc.subDir;
-      inherit configFiles executableToolDepends exeName;
+      inherit configFiles executableToolDepends exeName enableDWARF;
       exePath = drv + "/bin/${exeName}";
       env = shellWrappers;
       profiled = self (drvArgs // { enableLibraryProfiling = true; });
+      dwarf = self (drvArgs // { enableDWARF = true; });
     } // lib.optionalAttrs (haskellLib.isLibrary componentId) ({
         inherit haddock;
         inherit (haddock) haddockDir; # This is null if `doHaddock = false`

builder/ghc-for-component-wrapper.nix

@@ -7,14 +7,17 @@
 # database.
 
 { lib, stdenv, ghc, runCommand, lndir, makeWrapper, haskellLib
-}:
+}@defaults:
 
 { componentName  # Full derivation name of the component
 , configFiles    # The component's "config" derivation
 , postInstall ? ""
+, enableDWARF
 }:
 
 let
+  ghc = if enableDWARF then defaults.ghc.dwarf else defaults.ghc;
+
   inherit (configFiles) targetPrefix ghcCommand ghcCommandCaps packageCfgDir;
   libDir         = "$out/${configFiles.libDir}";
   docDir         = "$out/share/doc/ghc/html";

builder/haddock-builder.nix

@@ -54,6 +54,7 @@ let
   shellWrappers = ghcForComponent {
     componentName = fullName;
     configFiles = docsConfigFiles;
+    inherit (componentDrv) enableDWARF;
   };
 
   drv = stdenv.mkDerivation (commonAttrs // {

builder/make-config-files.nix

@@ -1,8 +1,10 @@
-{ stdenv, lib, haskellLib, ghc, nonReinstallablePkgs, runCommand, writeText, writeScript }:
+{ stdenv, lib, haskellLib, ghc, nonReinstallablePkgs, runCommand, writeText, writeScript }@defaults:
 
-{ identifier, component, fullName, flags ? {}, needsProfiling ? false, chooseDrv ? drv: drv }:
+{ identifier, component, fullName, flags ? {}, needsProfiling ? false, enableDWARF ? false, chooseDrv ? drv: drv }:
 
 let
+  ghc = if enableDWARF then defaults.ghc.dwarf else defaults.ghc;
+
   flagsAndConfig = field: xs: lib.optionalString (xs != []) ''
     echo ${lib.concatStringsSep " " (map (x: "--${field}=${x}") xs)} >> $out/configure-flags
     echo "${field}: ${lib.concatStringsSep " " xs}" >> $out/cabal.config
@@ -47,9 +49,10 @@ let
   # TODO investigate why this is needed
   # TODO find out why p ? configFiles helps (for instance for `R1909.aarch64-unknown-linux-gnu.tests.cabal-22.run.x86_64-linux`)
   libDeps = map chooseDrv (
-    (if needsProfiling then (x: map (p: p.profiled or p) x) else x: x)
+    (if enableDWARF then (x: map (p: p.dwarf or p) x) else x: x)
+    ((if needsProfiling then (x: map (p: p.profiled or p) x) else x: x)
     (lib.filter (p: (p ? configFiles) && p.configFiles.targetPrefix == ghc.targetPrefix)
-    (map getLibComponent component.depends))
+    (map getLibComponent component.depends)))
   );
   cfgFiles =
     let xs = map

builder/setup-builder.nix

@@ -1,12 +1,13 @@
 { pkgs, stdenv, lib, buildPackages, haskellLib, ghc, nonReinstallablePkgs, hsPkgs, makeSetupConfigFiles, pkgconfig }:
 
-{ component, package, name, src, flags ? {}, revision ? null, patches ? [], defaultSetupSrc
+let self =
+{ component, package, name, src, enableDWARF ? false, flags ? {}, revision ? null, patches ? [], defaultSetupSrc
 , preUnpack ? component.preUnpack, postUnpack ? component.postUnpack
 , prePatch ? null, postPatch ? null
 , preBuild ? component.preBuild , postBuild ? component.postBuild
 , preInstall ? component.preInstall , postInstall ? component.postInstall
 , cleanSrc ? haskellLib.cleanCabalComponent package component "setup" src
-}:
+}@drvArgs:
 
 let
   cleanSrc' = haskellLib.rootAndSubDir cleanSrc;
@@ -17,7 +18,7 @@ let
 
   configFiles = makeSetupConfigFiles {
     inherit (package) identifier;
-    inherit fullName flags component;
+    inherit fullName flags component enableDWARF;
   };
   hooks = haskellLib.optionalHooks {
     inherit
@@ -50,6 +51,7 @@ let
         srcSubDirPath = cleanSrc'.root + cleanSrc'.subDir;
         cleanSrc = cleanSrc';
         inherit configFiles;
+        dwarf = self (drvArgs // { enableDWARF = true; });
       };
 
       meta = {
@@ -94,4 +96,4 @@ let
     // (lib.optionalAttrs (patches != []) { patches = map (p: if builtins.isFunction p then p { inherit (package.identifier) version; inherit revision; } else p) patches; })
     // hooks
   );
-in drv
+in drv; in self

builder/shell-for.nix

@@ -16,6 +16,7 @@
 , exactDeps ? false
 , tools ? {}
 , packageSetupDeps ? true
+, enableDWARF ? false
 , ... } @ args:
 
 let
@@ -93,6 +94,7 @@ let
     postInstall = lib.optionalString withHoogle' ''
       ln -s ${hoogleIndex}/bin/hoogle $out/bin
     '';
+    inherit enableDWARF;
   };
 
   hoogleIndex = let

compiler/ghc/configured-src.nix

@@ -9,6 +9,7 @@
 , useLLVM, llvmPackages
 , targetCC
 , enableIntegerSimple, targetGmp
+, enableDWARF, elfutils
 , ncurses, targetLibffi, libiconv
 , disableLargeAddressSpace
 , buildMK
@@ -112,7 +113,11 @@ stdenv.mkDerivation (rec {
         "CFLAGS=-fuse-ld=gold"
         "CONF_GCC_LINKER_OPTS_STAGE1=-fuse-ld=gold"
         "CONF_GCC_LINKER_OPTS_STAGE2=-fuse-ld=gold"
-    ] ;
+    ] ++ lib.optionals enableDWARF [
+        "--enable-dwarf-unwind"
+        "--with-libdw-includes=${lib.getDev elfutils}/include"
+        "--with-libdw-libraries=${lib.getLib elfutils}/lib"
+    ];
 
     outputs = [ "out" ];
     phases = [ "unpackPhase" "patchPhase" ]

compiler/ghc/default.nix

@@ -3,11 +3,12 @@
 # haskell.nix ships its own version of the ghc expression as it needs more
 # control over the expression to isolate it against varying <nixpkgs> and
 # allow us to customize it to the way haskell.nix works.
+let self =
 { stdenv, lib, haskell-nix, targetPackages
 
 # build-tools
 , bootPkgs
-, autoconf, automake, coreutils, fetchurl, fetchpatch, perl, python3, m4, sphinx, numactl
+, autoconf, automake, coreutils, fetchurl, fetchpatch, perl, python3, m4, sphinx, numactl, elfutils
 , autoreconfHook
 , bash
 
@@ -37,6 +38,8 @@
 
 , enableLibraryProfiling ? true
 
+, enableDWARF ? false
+
 , # Whether to build terminfo.  Musl fails to build terminfo as ncurses seems to be linked to glibc
   enableTerminfo ? !stdenv.targetPlatform.isWindows && !stdenv.targetPlatform.isMusl
 
@@ -59,7 +62,7 @@
 
 # extra values we want to have available as passthru values.
 , extra-passthru ? {}
-}:
+}@args:
 
 assert !enableIntegerSimple -> gmp != null;
 
@@ -103,6 +106,9 @@ let
   '' + lib.optionalString enableRelocatedStaticLibs ''
     GhcLibHcOpts += -fPIC
     GhcRtsHcOpts += -fPIC
+  '' + lib.optionalString enableDWARF ''
+    GhcLibHcOpts += -g3
+    GhcRtsHcOpts += -g3
   '' + lib.optionalString targetPlatform.useAndroidPrebuilt ''
     EXTRA_CC_OPTS += -std=gnu99
   '' + lib.optionalString (!enableTerminfo) ''
@@ -149,6 +155,7 @@ let
     useLLVM llvmPackages
     targetCC
     enableIntegerSimple targetGmp
+    enableDWARF elfutils
     ncurses targetLibffi libiconv
     disableLargeAddressSpace
     buildMK
@@ -315,6 +322,12 @@ stdenv.mkDerivation (rec {
 
     # Used to detect non haskell-nix compilers (accidental use of nixpkgs compilers can lead to unexpected errors)
     isHaskellNixCompiler = true;
+
+    # The same GHC, but with debug enabled (if it can be)
+    dwarf = lib.makeOverridable self (args // {
+      enableDWARF = stdenv.targetPlatform.isLinux
+        && builtins.compareVersions ghc-version "8.10.2" >= 0;
+    });
   } // extra-passthru;
 
   meta = {
@@ -328,4 +341,5 @@ stdenv.mkDerivation (rec {
   dontStrip = true;
   dontPatchELF = true;
   noAuditTmpdir = true;
-})
+});
+in self

overlays/ghc.nix

@@ -21,7 +21,9 @@ final: prev: with prev;
        && !lib.hasPrefix "ghcjs" name
        && !lib.hasSuffix "Binary" name;
      overrideCompiler = compiler:
-       (compiler.override ghcPkgOverrides).overrideAttrs ghcDrvOverrides;
+       ((compiler.override ghcPkgOverrides).overrideAttrs ghcDrvOverrides) // {
+         dwarf = overrideCompiler compiler.dwarf;
+       };
    in
      lib.recursiveUpdate prev.haskell-nix {
        compiler = lib.mapAttrs (_name: overrideCompiler)

test/cabal-simple-debug/Main.hs

@@ -0,0 +1,4 @@
+module Main where
+
+main :: IO ()
+main = putStrLn "Hello, Haskell!"

test/cabal-simple-debug/Setup.hs

@@ -0,0 +1,2 @@
+import Distribution.Simple
+main = defaultMain

test/cabal-simple-debug/cabal-simple.cabal

@@ -0,0 +1,37 @@
+cabal-version:       >=1.10
+-- Initial package description 'cabal-simple.cabal' generated by 'cabal
+-- init'.  For further documentation, see
+-- http://haskell.org/cabal/users-guide/
+
+name:                cabal-simple
+version:             0.1.0.0
+-- synopsis:
+-- description:
+-- bug-reports:
+license:             PublicDomain
+author:              Rodney Lorrimar
+maintainer:          rodney.lorrimar@iohk.io
+-- category:
+build-type:          Simple
+
+library
+  -- exposed-modules:
+  -- other-modules:
+  -- other-extensions:
+  build-depends:       base
+                     , extra
+                     , safe
+                     , aeson
+  -- hs-source-dirs:
+  default-language:    Haskell2010
+
+executable cabal-simple
+  main-is:             Main.hs
+  -- other-modules:
+  -- other-extensions:
+  build-depends:       base
+                     , cabal-simple
+                     , extra
+                     , optparse-applicative
+  -- hs-source-dirs:
+  default-language:    Haskell2010

test/cabal-simple-debug/default.nix

@@ -0,0 +1,47 @@
+# Test a package set
+{ stdenv, lib, util, cabalProject', haskellLib, recurseIntoAttrs, testSrc, compiler-nix-name, dwarfdump }:
+
+with lib;
+
+let
+  project = cabalProject' {
+    inherit compiler-nix-name;
+    src = testSrc "cabal-simple-debug";
+  };
+
+  packages = project.hsPkgs;
+
+in recurseIntoAttrs {
+  ifdInputs = {
+    inherit (project) plan-nix;
+  };
+  run = stdenv.mkDerivation {
+    name = "cabal-simple-debug-test";
+
+    buildCommand = ''
+      exe="${(packages.cabal-simple.components.exes.cabal-simple.dwarf).exePath}"
+
+      size=$(command stat --format '%s' "$exe")
+      printf "size of executable $exe is $size. \n" >& 2
+
+      # fixme:
+      printf "checking whether executable included DWARF debug info... " >& 2
+      (${dwarfdump}/bin/dwarfdump $exe || true) | grep -c 'libraries/base/[A-Za-z0-9/]*\.hs'
+      (${dwarfdump}/bin/dwarfdump $exe || true) | grep -c '\/Main\.hs'
+
+      touch $out
+    '';
+
+    meta = {
+      platforms = platforms.all;
+      # DWARF only works on linux with GHC 8.10.2 and newer
+      disabled = compiler-nix-name == "ghc865" || compiler-nix-name == "ghc884"
+        || !stdenv.hostPlatform.isLinux || haskellLib.isCrossHost || stdenv.hostPlatform.isMusl;
+    };
+
+    passthru = {
+      # Used for debugging with nix repl
+      inherit project packages;
+    };
+  };
+}

test/default.nix

@@ -1,6 +1,6 @@
 { haskellNix ? import ../default.nix { inherit checkMaterialization; }
 , pkgs ? import nixpkgs nixpkgsArgs
-, nixpkgs ? haskellNix.sources.nixpkgs
+, nixpkgs ? haskellNix.sources.nixpkgs-unstable
 , nixpkgsArgs ? haskellNix.nixpkgsArgs
 , ifdLevel ? 1000
 , compiler-nix-name
@@ -212,6 +212,10 @@ let
     # githash runs git from TH code and this needs a cross compiled git exe
     # to work correctly.  Cross compiling git is currently brocken.
     githash = haskell-nix.callPackage ./githash { inherit compiler-nix-name; testSrc = testSrcWithGitDir; };
+  } // lib.optionalAttrs (
+      stdenv.hostPlatform.isLinux && !pkgs.haskell-nix.haskellLib.isCrossHost && !stdenv.hostPlatform.isMusl
+      && !(__elem compiler-nix-name ["ghc865" "ghc884"])) {
+    cabal-simple-debug = callTest ./cabal-simple-debug { inherit util compiler-nix-name; };
   };
 
   # This is the same as allTests, but filter out all the key/vaules from the