Fix AIX/ppc codegen in `-prof` compilation mode

The implementation in df26b95559fd467abc0a3a4151127c95cb5011b9
wrongly assumed that all C-ABI subroutine calls would use a
'ForeignLabel' but it turns out that calls inserted via
'emitRtsCall' use 'CmmLabel's instead.

1 files changed, 8 insertions, 2 deletions

diff --git a/compiler/nativeGen/PPC/Ppr.hs b/compiler/nativeGen/PPC/Ppr.hs
index 16e8dc14e0..59b0ad80d1 100644
--- a/compiler/nativeGen/PPC/Ppr.hs
+++ b/compiler/nativeGen/PPC/Ppr.hs
@@ -607,10 +607,16 @@ pprInstr (BCTR _ _) = hcat [
     ]
 pprInstr (BL lbl _) = do
     sdocWithPlatform $ \platform -> case platformOS platform of
-        OSAIX | isForeignLabel lbl ->
+        OSAIX ->
           -- On AIX, "printf" denotes a function-descriptor (for use
           -- by function pointers), whereas the actual entry-code
-          -- address is denoted by the dot-prefixed ".printf" label
+          -- address is denoted by the dot-prefixed ".printf" label.
+          -- Moreover, the PPC NCG only ever emits a BL instruction
+          -- for calling C ABI functions. Most of the time these calls
+          -- originate from FFI imports and have a 'ForeignLabel',
+          -- but when profiling the codegen inserts calls via
+          -- 'emitRtsCallGen' which are 'CmmLabel's even though
+          -- they'd technically be more like 'ForeignLabel's.
           hcat [
             text "\tbl\t.",
             ppr lbl