From acc47bd2d05c36e13fd0e27dfa8a698b34fa58e6 Mon Sep 17 00:00:00 2001
From: Matthew Pickering <matthewtpickering@gmail.com>
Date: Wed, 7 Jul 2021 11:19:47 +0100
Subject: [PATCH] packaging: Add note about wrappers
---
hadrian/src/Rules/BinaryDist.hs | 30 +++++++++++++++++++++++++++---
1 file changed, 27 insertions(+), 3 deletions(-)
diff --git a/hadrian/src/Rules/BinaryDist.hs b/hadrian/src/Rules/BinaryDist.hs
index 594bc55a1763..3c9414454032 100644
--- a/hadrian/src/Rules/BinaryDist.hs
+++ b/hadrian/src/Rules/BinaryDist.hs
@@ -38,10 +38,10 @@ It does so by following the steps below.
to
<build root/bindist/ghc-<X>.<Y>.<Z>-<arch>-<os>/bin/xxxx-<VER>
-- create symlink (or bash) wrapper to from unversioned to versioned executable:
- <build root/bindist/ghc-<X>.<Y>.<Z>-<arch>-<os>/bin/xxxx-<VER>
- points to:
+- create symlink (or bash) wrapper from unversioned to versioned executable:
<build root/bindist/ghc-<X>.<Y>.<Z>-<arch>-<os>/bin/xxxx
+ points to:
+ <build root/bindist/ghc-<X>.<Y>.<Z>-<arch>-<os>/bin/xxxx-<VER>
- copy the lib directories of the compiler we built:
<build root>/stage1/lib
@@ -317,6 +317,7 @@ wrapper "runghc" = runGhcWrapper
wrapper _ = commonWrapper
-- | Wrapper scripts for different programs. Common is default wrapper.
+-- See Note [Two Types of Wrappers]
ghcWrapper :: Action String
ghcWrapper = pure $ "exec \"$executablename\" -B\"$libdir\" ${1+\"$@\"}\n"
@@ -371,6 +372,7 @@ iservBins = do
]
-- Version wrapper scripts
+-- See Note [Two Types of Wrappers]
-- | Create a wrapper script calls the executable given as first argument
createVersionWrapper :: String -> FilePath -> Action ()
@@ -383,3 +385,25 @@ createVersionWrapper versioned_exe install_path = do
, "-DEXE_PATH=\"" ++ versioned_exe ++ "\""
, version_wrapper]
+{-
+Note [Two Types of Wrappers]
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+There are two different types of wrapper scripts.
+
+1. The wrapper scripts installed
+ <build root>/bindist/ghc-<X>.<Y>.<Z>-<arch>-<os>/wrappers/<program>
+2. The version wrapper scripts installed in
+ <build root/bindist/ghc-<X>.<Y>.<Z>-<arch>-<os>/bin/xxxx
+
+The purpose of the wrappers in (1) is to allow the executables to be installed
+into a different @BINDIR@ which is not already adjacent to a libdir. Therefore
+these wrappers pass the libdir and so on explicitliy to the executable so the
+wrappers can be placed anywhere and still work.
+
+The purpose of the wrappers in (2) is to provide both versioned and unversioned
+executables. On windows, these are actual wrapper scripts which just call the executable
+but on linux these wrappers are symlinks.
+
+-}
+
--
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