Add -finfo-table-map which maps info tables to source positions

This new flag embeds a lookup table from the address of an info table
to information about that info table.

The main interface for consulting the map is the `lookupIPE` C function

> InfoProvEnt * lookupIPE(StgInfoTable *info)

The `InfoProvEnt` has the following structure:

> typedef struct InfoProv_{
>     char * table_name;
>     char * closure_desc;
>     char * ty_desc;
>     char * label;
>     char * module;
>     char * srcloc;
> } InfoProv;
>
> typedef struct InfoProvEnt_ {
>     StgInfoTable * info;
>     InfoProv prov;
>     struct InfoProvEnt_ *link;
> } InfoProvEnt;

The source positions are approximated in a similar way to the source
positions for DWARF debugging information. They are only approximate but
in our experience provide a good enough hint about where the problem
might be. It is therefore recommended to use this flag in conjunction
with `-g<n>` for more accurate locations.

The lookup table is also emitted into the eventlog when it is available
as it is intended to be used with the `-hi` profiling mode.

Using this flag will significantly increase the size of the resulting
object file but only by a factor of 2-3x in our experience.

1 files changed, 4 insertions, 2 deletions

diff --git a/testsuite/tests/regalloc/regalloc_unit_tests.hs b/testsuite/tests/regalloc/regalloc_unit_tests.hs
index afc6fa0fca..cc4dcf7f9b 100644
--- a/testsuite/tests/regalloc/regalloc_unit_tests.hs
+++ b/testsuite/tests/regalloc/regalloc_unit_tests.hs
@@ -46,6 +46,7 @@ import GHC.Driver.Errors
 import GHC.Utils.Error
 import GHC.Utils.Outputable
 import GHC.Types.Basic
+import GHC.Unit.Home
 
 import GHC.Data.Stream as Stream (collect, yield)
 
@@ -114,7 +115,8 @@ compileCmmForRegAllocStats logger dflags' cmmFile ncgImplF us = do
     hscEnv <- newHscEnv dflags
 
     -- parse the cmm file and output any warnings or errors
-    (warnings, errors, parsedCmm) <- parseCmmFile dflags (hsc_home_unit hscEnv) cmmFile
+    let fake_mod = mkHomeModule (hsc_home_unit hscEnv) (mkModuleName "fake")
+    (warnings, errors, parsedCmm) <- parseCmmFile dflags fake_mod (hsc_home_unit hscEnv) cmmFile
     let warningMsgs = fmap pprWarning warnings
         errorMsgs   = fmap pprError errors
 
@@ -122,7 +124,7 @@ compileCmmForRegAllocStats logger dflags' cmmFile ncgImplF us = do
     mapM_ (printBagOfErrors logger dflags) [warningMsgs, errorMsgs]
 
     let initTopSRT = emptySRT thisMod
-    cmmGroup <- fmap snd $ cmmPipeline hscEnv initTopSRT $ fromJust parsedCmm
+    cmmGroup <- fmap snd $ cmmPipeline hscEnv initTopSRT $ fst $ fromJust parsedCmm
 
     rawCmms <- cmmToRawCmm logger dflags (Stream.yield cmmGroup)