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-rw-r--r--compiler/GHC/Cmm/CLabel.hs34
-rw-r--r--compiler/GHC/CmmToAsm.hs1
-rw-r--r--compiler/GHC/CmmToAsm/Config.hs4
-rw-r--r--compiler/GHC/CmmToAsm/Monad.hs2
-rw-r--r--compiler/GHC/CmmToAsm/X86/Ppr.hs11
-rw-r--r--compiler/GHC/Driver/Flags.hs1
-rw-r--r--compiler/GHC/Driver/Session.hs2
-rw-r--r--docs/users_guide/phases.rst13
8 files changed, 65 insertions, 3 deletions
diff --git a/compiler/GHC/Cmm/CLabel.hs b/compiler/GHC/Cmm/CLabel.hs
index 3d21855ec2..d5df2dd1c5 100644
--- a/compiler/GHC/Cmm/CLabel.hs
+++ b/compiler/GHC/Cmm/CLabel.hs
@@ -118,6 +118,7 @@ module GHC.Cmm.CLabel (
LabelStyle (..),
pprDebugCLabel,
pprCLabel,
+ ppInternalProcLabel,
-- * Others
dynamicLinkerLabelInfo,
@@ -1360,6 +1361,39 @@ pprCLabel platform sty lbl =
CmmLabel _ _ fs CmmRet -> maybe_underscore $ ftext fs <> text "_ret"
CmmLabel _ _ fs CmmClosure -> maybe_underscore $ ftext fs <> text "_closure"
+-- Note [Internal proc labels]
+-- ~~~~~~~~~~~~~~~~~~~~~~~~~~~
+--
+-- Some tools (e.g. the `perf` utility on Linux) rely on the symbol table
+-- for resolution of function names. To help these tools we provide the
+-- (enabled by default) -fexpose-all-symbols flag which causes GHC to produce
+-- symbols even for symbols with are internal to a module (although such
+-- symbols will have only local linkage).
+--
+-- Note that these labels are *not* referred to by code. They are strictly for
+-- diagnostics purposes.
+--
+-- To avoid confusion, it is desireable to add a module-qualifier to the
+-- symbol name. However, the Name type's Internal constructor doesn't carry
+-- knowledge of the current Module. Consequently, we have to pass this around
+-- explicitly.
+
+-- | Generate a label for a procedure internal to a module (if
+-- 'Opt_ExposeAllSymbols' is enabled).
+-- See Note [Internal proc labels].
+ppInternalProcLabel :: Module -- ^ the current module
+ -> CLabel
+ -> Maybe SDoc -- ^ the internal proc label
+ppInternalProcLabel this_mod (IdLabel nm _ flavour)
+ | isInternalName nm
+ = Just
+ $ text "_" <> ppr this_mod
+ <> char '_'
+ <> ztext (zEncodeFS (occNameFS (occName nm)))
+ <> char '_'
+ <> pprUniqueAlways (getUnique nm)
+ <> ppIdFlavor flavour
+ppInternalProcLabel _ _ = Nothing
ppIdFlavor :: IdLabelInfo -> SDoc
ppIdFlavor x = pp_cSEP <> case x of
diff --git a/compiler/GHC/CmmToAsm.hs b/compiler/GHC/CmmToAsm.hs
index af358d5dee..223eb33fb5 100644
--- a/compiler/GHC/CmmToAsm.hs
+++ b/compiler/GHC/CmmToAsm.hs
@@ -1190,5 +1190,6 @@ initNCGConfig dflags this_mod = NCGConfig
, ncgDwarfEnabled = debugLevel dflags > 0
, ncgDwarfUnwindings = debugLevel dflags >= 1
, ncgDwarfStripBlockInfo = debugLevel dflags < 2 -- We strip out block information when running with -g0 or -g1.
+ , ncgExposeInternalSymbols = gopt Opt_ExposeInternalSymbols dflags
}
diff --git a/compiler/GHC/CmmToAsm/Config.hs b/compiler/GHC/CmmToAsm/Config.hs
index b3dd1df1ca..141f1168be 100644
--- a/compiler/GHC/CmmToAsm/Config.hs
+++ b/compiler/GHC/CmmToAsm/Config.hs
@@ -18,8 +18,7 @@ import GHC.Utils.Outputable
data NCGConfig = NCGConfig
{ ncgPlatform :: !Platform -- ^ Target platform
, ncgAsmContext :: !SDocContext -- ^ Context for ASM code generation
- , ncgThisModule :: !Module -- ^ The name of the module we are currently compiling (for generating debug information)
- -- See Note [Internal proc labels] in CLabel.
+ , ncgThisModule :: !Module -- ^ The name of the module we are currently compiling
, ncgProcAlignment :: !(Maybe Int) -- ^ Mandatory proc alignment
, ncgExternalDynamicRefs :: !Bool -- ^ Generate code to link against dynamic libraries
, ncgPIC :: !Bool -- ^ Enable Position-Independent Code
@@ -40,6 +39,7 @@ data NCGConfig = NCGConfig
, ncgDwarfEnabled :: !Bool -- ^ Enable Dwarf generation
, ncgDwarfUnwindings :: !Bool -- ^ Enable unwindings
, ncgDwarfStripBlockInfo :: !Bool -- ^ Strip out block information from generated Dwarf
+ , ncgExposeInternalSymbols :: !Bool -- ^ Expose symbol table entries for internal symbols
}
-- | Return Word size
diff --git a/compiler/GHC/CmmToAsm/Monad.hs b/compiler/GHC/CmmToAsm/Monad.hs
index 5f306bf8d6..8fb834ec7a 100644
--- a/compiler/GHC/CmmToAsm/Monad.hs
+++ b/compiler/GHC/CmmToAsm/Monad.hs
@@ -80,6 +80,8 @@ data NcgImpl statics instr jumpDest = NcgImpl {
canShortcut :: instr -> Maybe jumpDest,
shortcutStatics :: (BlockId -> Maybe jumpDest) -> statics -> statics,
shortcutJump :: (BlockId -> Maybe jumpDest) -> instr -> instr,
+ -- | 'Module' is only for printing internal labels. See Note [Internal proc
+ -- labels] in CLabel.
pprNatCmmDecl :: NatCmmDecl statics instr -> SDoc,
maxSpillSlots :: Int,
allocatableRegs :: [RealReg],
diff --git a/compiler/GHC/CmmToAsm/X86/Ppr.hs b/compiler/GHC/CmmToAsm/X86/Ppr.hs
index b9fe4c0260..16e54fedc6 100644
--- a/compiler/GHC/CmmToAsm/X86/Ppr.hs
+++ b/compiler/GHC/CmmToAsm/X86/Ppr.hs
@@ -90,6 +90,7 @@ pprNatCmmDecl config proc@(CmmProc top_info lbl _ (ListGraph blocks)) =
-- special case for code without info table:
pprSectionAlign config (Section Text lbl) $$
pprProcAlignment config $$
+ pprProcLabel config lbl $$
pprLabel platform lbl $$ -- blocks guaranteed not null, so label needed
vcat (map (pprBasicBlock config top_info) blocks) $$
(if ncgDwarfEnabled config
@@ -99,6 +100,7 @@ pprNatCmmDecl config proc@(CmmProc top_info lbl _ (ListGraph blocks)) =
Just (CmmStaticsRaw info_lbl _) ->
pprSectionAlign config (Section Text info_lbl) $$
pprProcAlignment config $$
+ pprProcLabel config lbl $$
(if platformHasSubsectionsViaSymbols platform
then pdoc platform (mkDeadStripPreventer info_lbl) <> char ':'
else empty) $$
@@ -114,6 +116,15 @@ pprNatCmmDecl config proc@(CmmProc top_info lbl _ (ListGraph blocks)) =
else empty) $$
pprSizeDecl platform info_lbl
+-- | Output an internal proc label. See Note [Internal proc labels] in CLabel.
+pprProcLabel :: NCGConfig -> CLabel -> SDoc
+pprProcLabel config lbl
+ | ncgExposeInternalSymbols config
+ , Just lbl' <- ppInternalProcLabel (ncgThisModule config) lbl
+ = lbl' <> char ':'
+ | otherwise
+ = empty
+
-- | Output the ELF .size directive.
pprSizeDecl :: Platform -> CLabel -> SDoc
pprSizeDecl platform lbl
diff --git a/compiler/GHC/Driver/Flags.hs b/compiler/GHC/Driver/Flags.hs
index e228c416be..b7d3d4d459 100644
--- a/compiler/GHC/Driver/Flags.hs
+++ b/compiler/GHC/Driver/Flags.hs
@@ -274,6 +274,7 @@ data GeneralFlag
-- forwards all -L flags to the collect2 command without using a
-- response file and as such breaking apart.
| Opt_SingleLibFolder
+ | Opt_ExposeInternalSymbols
| Opt_KeepCAFs
| Opt_KeepGoing
| Opt_ByteCode
diff --git a/compiler/GHC/Driver/Session.hs b/compiler/GHC/Driver/Session.hs
index 7db08595d7..4c53e56f3d 100644
--- a/compiler/GHC/Driver/Session.hs
+++ b/compiler/GHC/Driver/Session.hs
@@ -376,7 +376,6 @@ import qualified GHC.LanguageExtensions as LangExt
-- -----------------------------------------------------------------------------
-- DynFlags
-
-- | Used to differentiate the scope an include needs to apply to.
-- We have to split the include paths to avoid accidentally forcing recursive
-- includes since -I overrides the system search paths. See #14312.
@@ -3417,6 +3416,7 @@ fFlagsDeps = [
flagSpec "error-spans" Opt_ErrorSpans,
flagSpec "excess-precision" Opt_ExcessPrecision,
flagSpec "expose-all-unfoldings" Opt_ExposeAllUnfoldings,
+ flagSpec "expose-internal-symbols" Opt_ExposeInternalSymbols,
flagSpec "external-dynamic-refs" Opt_ExternalDynamicRefs,
flagSpec "external-interpreter" Opt_ExternalInterpreter,
flagSpec "flat-cache" Opt_FlatCache,
diff --git a/docs/users_guide/phases.rst b/docs/users_guide/phases.rst
index 1d22372889..88b6659a05 100644
--- a/docs/users_guide/phases.rst
+++ b/docs/users_guide/phases.rst
@@ -720,6 +720,19 @@ Options affecting code generation
all target platforms. See the :ghc-flag:`--print-object-splitting-supported`
flag to check whether your GHC supports object splitting.
+.. ghc-flag:: -fexpose-internal-symbols
+ :shortdesc: Produce symbols for all functions, including internal functions.
+ :type: dynamic
+ :category: codegen
+
+ Request that GHC emits verbose symbol tables which include local symbols
+ for module-internal functions. These can be useful for tools like
+ :ref:`perf <https://perf.wiki.kernel.org/>` but increase object file sizes.
+
+ :ghc-flag:`-fno-expose-internal-symbols` suppresses all non-global symbol
+ table entries, resulting in smaller object file sizes at the expense of
+ debuggability.
+
.. _options-linker:
Options affecting linking
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