diff options
| -rw-r--r-- | compiler/GHC/CmmToAsm/Dwarf/Types.hs | 24 |
1 files changed, 19 insertions, 5 deletions
diff --git a/compiler/GHC/CmmToAsm/Dwarf/Types.hs b/compiler/GHC/CmmToAsm/Dwarf/Types.hs index 736af3e942..cad6a63515 100644 --- a/compiler/GHC/CmmToAsm/Dwarf/Types.hs +++ b/compiler/GHC/CmmToAsm/Dwarf/Types.hs @@ -178,7 +178,8 @@ pprDwarfInfoOpen platform haveSrc (DwarfCompileUnit _ name producer compDir lowL $$ pprString producer $$ pprData4 dW_LANG_Haskell $$ pprString compDir - $$ pprWord platform (pdoc platform lowLabel) + -- Offset due to Note [Info Offset] + $$ pprWord platform (pdoc platform lowLabel <> text "-1") $$ pprWord platform (pdoc platform highLabel) $$ if haveSrc then sectionOffset platform (ptext lineLbl) (ptext dwarfLineLabel) @@ -189,7 +190,8 @@ pprDwarfInfoOpen platform _ (DwarfSubprogram _ name label parent) = $$ pprString name $$ pprLabelString platform label $$ pprFlag (externallyVisibleCLabel label) - $$ pprWord platform (pdoc platform label) + -- Offset due to Note [Info Offset] + $$ pprWord platform (pdoc platform label <> text "-1") $$ pprWord platform (pdoc platform $ mkAsmTempProcEndLabel label) $$ pprByte 1 $$ pprByte dW_OP_call_frame_cfa @@ -256,7 +258,10 @@ pprDwarfARanges platform arngs unitU = $$ pprWord platform (char '0') pprDwarfARange :: Platform -> DwarfARange -> SDoc -pprDwarfARange platform arng = pprWord platform (pdoc platform $ dwArngStartLabel arng) $$ pprWord platform length +pprDwarfARange platform arng = + -- Offset due to Note [Info offset]. + pprWord platform (pdoc platform (dwArngStartLabel arng) <> text "-1") + $$ pprWord platform length where length = pdoc platform (dwArngEndLabel arng) <> char '-' <> pdoc platform (dwArngStartLabel arng) @@ -356,7 +361,7 @@ pprFrameProc platform frameLbl initUw (DwarfFrameProc procLbl hasInfo blocks) fdeEndLabel = mkAsmTempDerivedLabel procLbl (fsLit "_fde_end") procEnd = mkAsmTempProcEndLabel procLbl ifInfo str = if hasInfo then text str else empty - -- see [Note: Info Offset] + -- see Note [Info Offset] in vcat [ whenPprDebug $ text "# Unwinding for" <+> pdoc platform procLbl <> colon , pprData4' (pdoc platform fdeEndLabel <> char '-' <> pdoc platform fdeLabel) , pdoc platform fdeLabel <> colon @@ -398,7 +403,7 @@ pprFrameBlock platform (DwarfFrameBlock hasInfo uws0) = in if oldUws == uws then (empty, oldUws) - else let -- see [Note: Info Offset] + else let -- see Note [Info Offset] needsOffset = firstDecl && hasInfo lblDoc = pdoc platform lbl <> if needsOffset then text "-1" else empty @@ -407,6 +412,7 @@ pprFrameBlock platform (DwarfFrameBlock hasInfo uws0) = in (doc, uws) -- Note [Info Offset] +-- ~~~~~~~~~~~~~~~~~~ -- -- GDB was pretty much written with C-like programs in mind, and as a -- result they assume that once you have a return address, it is a @@ -426,6 +432,14 @@ pprFrameBlock platform (DwarfFrameBlock hasInfo uws0) = -- correct function name for the frame, as that uses the symbol table, -- which we can not manipulate as easily. -- +-- We apply this offset in several places: +-- +-- * unwind information in .debug_frames +-- * the subprogram and lexical_block DIEs in .debug_info +-- * the ranges in .debug_aranges +-- +-- In the latter two cases we apply the offset unconditionally. +-- -- There's a GDB patch to address this at [1]. At the moment of writing -- it's not merged, so I recommend building GDB with the patch if you -- care about unwinding. The hack above doesn't cover every case. |