RTS: Fix CloneStack.c when no table next to codewip/T20879

Function `lookupIPE` does not modify its argument. Reflect this in the
type. Module `CloneStack.c` relies on this for RTS without tables
next to code.

Fixes #20879

2 files changed, 2 insertions, 2 deletions

diff --git a/rts/IPE.c b/rts/IPE.c
index 19db89a063..faa2ab1ecb 100644
--- a/rts/IPE.c
+++ b/rts/IPE.c
@@ -157,7 +157,7 @@ void registerInfoProvList(InfoProvEnt **ent_list) {
     RELEASE_LOCK(&ipeMapLock);
 }
 
-InfoProvEnt *lookupIPE(StgInfoTable *info) {
+InfoProvEnt *lookupIPE(const StgInfoTable *info) {
     updateIpeMap();
     return lookupHashTable(ipeMap, (StgWord)info);
 }
diff --git a/rts/include/rts/IPE.h b/rts/include/rts/IPE.h
index 07026979d8..0cfe3e2fb3 100644
--- a/rts/include/rts/IPE.h
+++ b/rts/include/rts/IPE.h
@@ -28,4 +28,4 @@ typedef struct InfoProvEnt_ {
 } InfoProvEnt;
 
 void registerInfoProvList(InfoProvEnt **cc_list);
-InfoProvEnt *lookupIPE(StgInfoTable *info);
+InfoProvEnt *lookupIPE(const StgInfoTable *info);