Mark system and internal symbols as private symbols in asm

Summary:
This marks system and internal symbols as private in asm output so those
random generated sysmbols won't appear in .symtab

Reasoning:
 * internal symbols don't help to debug because names are just random
 * the symbols style breaks perf logic
 * internal symbols can take ~75% of the .symtab. In the same time
   .symtab can take about 20% of the binary file size

Notice:
This diff mostly makes sense on top of the D4713 (or similar)

Test Plan:
tests

Perf from D4713
```
     7.97%  FibbSlow  FibbSlow            [.] c3rM_info
     6.75%  FibbSlow  FibbSlow            [.] 0x000000000032cfa8
     6.63%  FibbSlow  FibbSlow            [.] cifA_info
     4.98%  FibbSlow  FibbSlow            [.] integerzmgmp_GHCziIntegerziType_eqIntegerzh_info
     4.55%  FibbSlow  FibbSlow            [.] chXn_info
     4.52%  FibbSlow  FibbSlow            [.] c3rH_info
     4.45%  FibbSlow  FibbSlow            [.] chZB_info
     4.04%  FibbSlow  FibbSlow            [.] Main_fibbzuslow_info
     4.03%  FibbSlow  FibbSlow            [.] stg_ap_0_fast
     3.76%  FibbSlow  FibbSlow            [.] chXA_info
     3.67%  FibbSlow  FibbSlow            [.] cifu_info
     3.25%  FibbSlow  FibbSlow            [.] ci4r_info
     2.64%  FibbSlow  FibbSlow            [.] s3rf_info
     2.42%  FibbSlow  FibbSlow            [.] s3rg_info
     2.39%  FibbSlow  FibbSlow            [.] integerzmgmp_GHCziIntegerziType_eqInteger_info
     2.25%  FibbSlow  FibbSlow            [.] integerzmgmp_GHCziIntegerziType_minusInteger_info
     2.17%  FibbSlow  FibbSlow            [.] ghczmprim_GHCziClasses_zeze_info
     2.09%  FibbSlow  FibbSlow            [.] cicc_info
     2.03%  FibbSlow  FibbSlow            [.] 0x0000000000331e15
     2.02%  FibbSlow  FibbSlow            [.] s3ri_info
     1.91%  FibbSlow  FibbSlow            [.] 0x0000000000331bb8
     1.89%  FibbSlow  FibbSlow            [.] ci4N_info
...
```

Perf from this patch:
```
    15.37%  FibbSlow  FibbSlow            [.] Main_fibbzuslow_info
    15.33%  FibbSlow  FibbSlow            [.] integerzmgmp_GHCziIntegerziType_minusInteger_info
    13.34%  FibbSlow  FibbSlow            [.] integerzmgmp_GHCziIntegerziType_eqIntegerzh_info
     9.24%  FibbSlow  FibbSlow            [.] integerzmgmp_GHCziIntegerziType_plusInteger_info
     9.08%  FibbSlow  FibbSlow            [.] frame_dummy
     8.25%  FibbSlow  FibbSlow            [.] integerzmgmp_GHCziIntegerziType_eqInteger_info
     4.29%  FibbSlow  FibbSlow            [.] 0x0000000000321ab0
     3.84%  FibbSlow  FibbSlow            [.] stg_ap_0_fast
     3.07%  FibbSlow  FibbSlow            [.] ghczmprim_GHCziClasses_zeze_info
     2.39%  FibbSlow  FibbSlow            [.] 0x0000000000321ab7
     1.90%  FibbSlow  FibbSlow            [.] 0x00000000003266b8
     1.88%  FibbSlow  FibbSlow            [.] base_GHCziNum_zm_info
     1.83%  FibbSlow  FibbSlow            [.] 0x0000000000326915
     1.34%  FibbSlow  FibbSlow            [.] 0x00000000003248cc
     1.07%  FibbSlow  FibbSlow            [.] base_GHCziNum_zp_info
     0.98%  FibbSlow  FibbSlow            [.] 0x00000000003247c8
     0.80%  FibbSlow  FibbSlow            [.] 0x0000000000121498
     0.79%  FibbSlow  FibbSlow            [.] stg_gc_noregs
     0.75%  FibbSlow  FibbSlow            [.] 0x0000000000321ad6
     0.67%  FibbSlow  FibbSlow            [.] 0x0000000000321aca
     0.64%  FibbSlow  FibbSlow            [.] 0x0000000000321b4a
     0.61%  FibbSlow  FibbSlow            [.] 0x00000000002ff633
```

Reviewers: simonmar, niteria, bgamari

Reviewed By: simonmar

Subscribers: lelf, angerman, olsner, rwbarton, thomie, carter

Differential Revision: https://phabricator.haskell.org/D4722

1 files changed, 38 insertions, 17 deletions

diff --git a/compiler/cmm/CLabel.hs b/compiler/cmm/CLabel.hs
index 1a9bc73add..1ba0d89c37 100644
--- a/compiler/cmm/CLabel.hs
+++ b/compiler/cmm/CLabel.hs
@@ -1135,20 +1135,12 @@ instance Outputable CLabel where
 
 pprCLabel :: Platform -> CLabel -> SDoc
 
-pprCLabel platform (LocalBlockLabel u)
-  =  getPprStyle $ \ sty ->
-     if asmStyle sty then
-        ptext (asmTempLabelPrefix platform) <> pprUniqueAlways u
-     else
-        char '_' <> pprUniqueAlways u
+pprCLabel _ (LocalBlockLabel u)
+  =  tempLabelPrefixOrUnderscore <> pprUniqueAlways u
 
 pprCLabel platform (AsmTempLabel u)
  | not (platformUnregisterised platform)
-  =  getPprStyle $ \ sty ->
-     if asmStyle sty then
-        ptext (asmTempLabelPrefix platform) <> pprUniqueAlways u
-     else
-        char '_' <> pprUniqueAlways u
+  =  tempLabelPrefixOrUnderscore <> pprUniqueAlways u
 
 pprCLabel platform (AsmTempDerivedLabel l suf)
  | cGhcWithNativeCodeGen == "YES"
@@ -1168,7 +1160,15 @@ pprCLabel _ PicBaseLabel
 
 pprCLabel platform (DeadStripPreventer lbl)
  | cGhcWithNativeCodeGen == "YES"
-   = pprCLabel platform lbl <> text "_dsp"
+   =
+   {-
+      `lbl` can be temp one but we need to ensure that dsp label will stay
+      in the final binary so we prepend non-temp prefix ("dsp_") and
+      optional `_` (underscore) because this is how you mark non-temp symbols
+      on some platforms (Darwin)
+   -}
+   maybe_underscore $ text "dsp_"
+   <> pprCLabel platform lbl <> text "_dsp"
 
 pprCLabel _ (StringLitLabel u)
  | cGhcWithNativeCodeGen == "YES"
@@ -1199,9 +1199,11 @@ pprCLbl (StringLitLabel u)
   = pprUniqueAlways u <> text "_str"
 
 pprCLbl (SRTLabel u)
-  = pprUniqueAlways u <> pp_cSEP <> text "srt"
+  = tempLabelPrefixOrUnderscore <> pprUniqueAlways u <> pp_cSEP <> text "srt"
 
-pprCLbl (LargeBitmapLabel u)  = text "b" <> pprUniqueAlways u <> pp_cSEP <> text "btm"
+pprCLbl (LargeBitmapLabel u)  =
+  tempLabelPrefixOrUnderscore
+  <> char 'b' <> pprUniqueAlways u <> pp_cSEP <> text "btm"
 -- Some bitsmaps for tuple constructors have a numeric tag (e.g. '7')
 -- until that gets resolved we'll just force them to start
 -- with a letter so the label will be legal assembly code.
@@ -1211,7 +1213,8 @@ pprCLbl (CmmLabel _ str CmmCode)        = ftext str
 pprCLbl (CmmLabel _ str CmmData)        = ftext str
 pprCLbl (CmmLabel _ str CmmPrimCall)    = ftext str
 
-pprCLbl (LocalBlockLabel u)             = text "blk_" <> pprUniqueAlways u
+pprCLbl (LocalBlockLabel u)             =
+    tempLabelPrefixOrUnderscore <> text "blk_" <> pprUniqueAlways u
 
 pprCLbl (RtsLabel (RtsApFast str))   = ftext str <> text "_fast"
 
@@ -1275,7 +1278,8 @@ pprCLbl (RtsLabel (RtsSlowFastTickyCtr pat))
 pprCLbl (ForeignLabel str _ _ _)
   = ftext str
 
-pprCLbl (IdLabel name _cafs flavor) = ppr name <> ppIdFlavor flavor
+pprCLbl (IdLabel name _cafs flavor) =
+  internalNamePrefix name <> ppr name <> ppIdFlavor flavor
 
 pprCLbl (CC_Label cc)           = ppr cc
 pprCLbl (CCS_Label ccs)         = ppr ccs
@@ -1318,6 +1322,24 @@ instance Outputable ForeignLabelSource where
         ForeignLabelInThisPackage       -> parens $ text "this package"
         ForeignLabelInExternalPackage   -> parens $ text "external package"
 
+internalNamePrefix :: Name -> SDoc
+internalNamePrefix name = getPprStyle $ \ sty ->
+  if codeStyle sty && isRandomGenerated then
+    sdocWithPlatform $ \platform ->
+      ptext (asmTempLabelPrefix platform)
+  else
+    empty
+  where
+    isRandomGenerated = not $ isExternalName name
+
+tempLabelPrefixOrUnderscore :: SDoc
+tempLabelPrefixOrUnderscore = sdocWithPlatform $ \platform ->
+  getPprStyle $ \ sty ->
+   if asmStyle sty then
+      ptext (asmTempLabelPrefix platform)
+   else
+      char '_'
+
 -- -----------------------------------------------------------------------------
 -- Machine-dependent knowledge about labels.
 
@@ -1390,4 +1412,3 @@ pprDynamicLinkerAsmLabel platform dllInfo lbl =
           SymbolPtr       -> text ".LC_" <> ppr lbl
           GotSymbolPtr    -> ppr lbl <> text "@got"
           GotSymbolOffset -> ppr lbl <> text "@gotoff"
-