Use a stack size slightly smaller than 1MB

.travis.yml

@@ -36,6 +36,7 @@ matrix:
     - os: osx
       before_install:
         - HOMEBREW_NO_AUTO_UPDATE=1 HOMEBREW_NO_INSTALL_CLEANUP=1 brew install ccache
+        - ulimit -n 1024 # increase the open files limit from the default of 512
       env:
         - NPROC=2
   allow_failures:

Makefile

@@ -106,6 +106,9 @@ ifneq ($(USE_LIBBACKTRACE), 0)
 deps: | libbacktrace
 endif
 
+# maximum stack size (in bytes) mirroring Android limits
+NIM_PARAMS := $(NIM_PARAMS) -d:stack_size=1000000
+
 #- deletes and recreates "beacon_chain.nims" which on Windows is a copy instead of a proper symlink
 update: | update-common
 	rm -f beacon_chain.nims && \

README.md

@@ -414,6 +414,12 @@ make -j$(nproc) NIMFLAGS="-d:release" USE_MULTITAIL=yes eth2_network_simulation
 make USE_LIBBACKTRACE=0 # expect the resulting binaries to be 2-3 times slower
 ```
 
+- show (some) C compiler warnings:
+
+```bash
+make NIMFLAGS="-d:cwarnings" beacon_node
+```
+
 - publish a book using [mdBook](https://github.com/rust-lang/mdBook) from sources in "docs/" to GitHub pages:
 
 ```bash

beacon_chain/beacon_node.nim

@@ -28,6 +28,9 @@ import
   sync_protocol, request_manager, keystore_management, interop, statusbar,
   sync_manager, validator_duties, validator_api, attestation_aggregation
 
+when defined(posix):
+  import posix
+
 const
   genesisFile* = "genesis.ssz"
   timeToInitNetworkingBeforeGenesis = chronos.seconds(30)
@@ -1119,6 +1122,7 @@ programMain:
 
   setupMainProc(config.logLevel)
 
+  ## handle command line arguments
   case config.cmd
   of createTestnet:
     var

config.nims

@@ -1,13 +1,24 @@
+import strutils
+
 if defined(release):
   switch("nimcache", "nimcache/release/$projectName")
 else:
   switch("nimcache", "nimcache/debug/$projectName")
 
+const stack_size {.intdefine.}: int = 0
+when defined(stack_size):
+  when defined(gcc):
+    # conservative compile-time estimation for single functions
+    switch("passC", "-Werror=stack-usage=" & $stack_size)
+  when defined(posix):
+    # limit the stack at runtime, on POSIX systems
+    switch("import", "stew/rlimits")
+  when defined(windows):
+    switch("passL", "-Wl,--stack," & $stack_size)
+
 if defined(windows):
   # disable timestamps in Windows PE headers - https://wiki.debian.org/ReproducibleBuilds/TimestampsInPEBinaries
   switch("passL", "-Wl,--no-insert-timestamp")
-  # increase stack size
-  switch("passL", "-Wl,--stack,8388608")
   # https://github.com/nim-lang/Nim/issues/4057
   --tlsEmulation:off
   if defined(i386):
@@ -59,9 +70,25 @@ else:
   --stacktrace:on
   --linetrace:on
 
-# the default open files limit is too low on macOS (512), breaking the
-# "--debugger:native" build. It can be increased with `ulimit -n 1024`.
-if not defined(macosx):
+var canEnableDebuggingSymbols = true
+if defined(macosx):
+  # The default open files limit is too low on macOS (512), breaking the
+  # "--debugger:native" build. It can be increased with `ulimit -n 1024`.
+  let openFilesLimitTarget = 1024
+  var openFilesLimit = 0
+  try:
+    openFilesLimit = staticExec("ulimit -n").strip(chars = Whitespace + Newlines).parseInt()
+    if openFilesLimit < openFilesLimitTarget:
+      echo "Open files limit too low to enable debugging symbols and lightweight stack traces."
+      echo "Increase it with \"ulimit -n " & $openFilesLimitTarget & "\""
+      canEnableDebuggingSymbols = false
+  except:
+    echo "ulimit error"
+# We ignore this resource limit on Windows, where a default `ulimit -n` of 256
+# in Git Bash is apparently ignored by the OS, and on Linux where the default of
+# 1024 is good enough for us.
+
+if canEnableDebuggingSymbols:
   # add debugging symbols and original files and line numbers
   --debugger:native
 

nim.cfg

@@ -0,0 +1,9 @@
+# can't do this in "config.nims", probably due to parsing order
+@if cwarnings:
+  @if windows:
+    gcc.options.always = "-mno-ms-bitfields -Wno-discarded-qualifiers -Wno-incompatible-pointer-types"
+  @else:
+    gcc.options.always = "-Wno-discarded-qualifiers -Wno-incompatible-pointer-types"
+  @end
+@end
+