Restructure compilation pipeline to allow hooks

This commit exposes GHC's internal compiler pipeline through a `Hooks`
module in the GHC API. It currently allows you to hook:

 * Foreign import/exports declarations
 * The frontend up to type checking
 * The one shot compilation mode
 * Core compilation, and the module iface
 * Linking and the phases in DriverPhases.hs
 * Quasiquotation

Authored-by: Luite Stegeman <stegeman@gmail.com>
Authored-by: Edsko de Vries <edsko@well-typed.com>
Signed-off-by: Austin Seipp <austin@well-typed.com>

1 files changed, 9 insertions, 0 deletions

diff --git a/compiler/main/Hooks.lhs-boot b/compiler/main/Hooks.lhs-boot
new file mode 100644
index 0000000000..71b7bf2a7d
--- /dev/null
+++ b/compiler/main/Hooks.lhs-boot
@@ -0,0 +1,9 @@
+\begin{code}
+module Hooks where
+
+data Hooks
+
+emptyHooks :: Hooks
+
+\end{code}
+