diff options
| -rw-r--r-- | compiler/cmm/CmmLayoutStack.hs | 62 | ||||
| -rw-r--r-- | compiler/cmm/Debug.hs | 91 | ||||
| -rw-r--r-- | compiler/nativeGen/Dwarf/Types.hs | 6 | ||||
| -rw-r--r-- | rts/Exception.cmm | 1 | ||||
| -rw-r--r-- | testsuite/driver/testglobals.py | 6 | ||||
| -rw-r--r-- | testsuite/driver/testlib.py | 6 | ||||
| -rw-r--r-- | testsuite/mk/test.mk | 14 | ||||
| -rw-r--r-- | testsuite/tests/codeGen/should_compile/Makefile | 5 | ||||
| -rw-r--r-- | testsuite/tests/codeGen/should_compile/T14999.cmm | 11 | ||||
| -rw-r--r-- | testsuite/tests/codeGen/should_compile/T14999.stdout | 16 | ||||
| -rw-r--r-- | testsuite/tests/codeGen/should_compile/all.T | 5 |
11 files changed, 185 insertions, 38 deletions
diff --git a/compiler/cmm/CmmLayoutStack.hs b/compiler/cmm/CmmLayoutStack.hs index d2525d1ffd..1d6c209953 100644 --- a/compiler/cmm/CmmLayoutStack.hs +++ b/compiler/cmm/CmmLayoutStack.hs @@ -577,15 +577,8 @@ makeFixupBlock dflags sp0 l stack tscope assigs | otherwise = do tmp_lbl <- newBlockId let sp_off = sp0 - sm_sp stack - maybeAddUnwind block - | debugLevel dflags > 0 - = block `blockSnoc` CmmUnwind [(Sp, Just unwind_val)] - | otherwise - = block - where unwind_val = cmmOffset dflags spExpr (sm_sp stack) block = blockJoin (CmmEntry tmp_lbl tscope) - ( maybeAddSpAdj dflags sp_off - $ maybeAddUnwind + ( maybeAddSpAdj dflags sp0 sp_off $ blockFromList assigs ) (CmmBranch l) return (tmp_lbl, [block]) @@ -851,28 +844,7 @@ manifestSp dflags stackmaps stack0 sp0 sp_high adj_pre_sp = mapExpDeep (areaToSp dflags sp0 sp_high area_off) adj_post_sp = mapExpDeep (areaToSp dflags (sp0 - sp_off) sp_high area_off) - -- Add unwind pseudo-instruction at the beginning of each block to - -- document Sp level for debugging - add_initial_unwind block - | debugLevel dflags > 0 - = CmmUnwind [(Sp, Just sp_unwind)] `blockCons` block - | otherwise - = block - where sp_unwind = CmmRegOff spReg (sp0 - wORD_SIZE dflags) - - -- Add unwind pseudo-instruction right before the Sp adjustment - -- if there is one. - add_adj_unwind block - | debugLevel dflags > 0 - , sp_off /= 0 - = block `blockSnoc` CmmUnwind [(Sp, Just sp_unwind)] - | otherwise - = block - where sp_unwind = CmmRegOff spReg (sp0 - wORD_SIZE dflags - sp_off) - - final_middle = maybeAddSpAdj dflags sp_off - . add_adj_unwind - . add_initial_unwind + final_middle = maybeAddSpAdj dflags sp0 sp_off . blockFromList . map adj_pre_sp . elimStackStores stack0 stackmaps area_off @@ -891,11 +863,33 @@ getAreaOff stackmaps (Young l) = Nothing -> pprPanic "getAreaOff" (ppr l) -maybeAddSpAdj :: DynFlags -> ByteOff -> Block CmmNode O O -> Block CmmNode O O -maybeAddSpAdj _ 0 block = block -maybeAddSpAdj dflags sp_off block = block `blockSnoc` adj +maybeAddSpAdj + :: DynFlags -> ByteOff -> ByteOff -> Block CmmNode O O -> Block CmmNode O O +maybeAddSpAdj dflags sp0 sp_off block = + add_initial_unwind $ add_adj_unwind $ adj block where - adj = CmmAssign spReg (cmmOffset dflags spExpr sp_off) + adj block + | sp_off /= 0 + = block `blockSnoc` CmmAssign spReg (cmmOffset dflags spExpr sp_off) + | otherwise = block + -- Add unwind pseudo-instruction at the beginning of each block to + -- document Sp level for debugging + add_initial_unwind block + | debugLevel dflags > 0 + = CmmUnwind [(Sp, Just sp_unwind)] `blockCons` block + | otherwise + = block + where sp_unwind = CmmRegOff spReg (sp0 - wORD_SIZE dflags) + + -- Add unwind pseudo-instruction right after the Sp adjustment + -- if there is one. + add_adj_unwind block + | debugLevel dflags > 0 + , sp_off /= 0 + = block `blockSnoc` CmmUnwind [(Sp, Just sp_unwind)] + | otherwise + = block + where sp_unwind = CmmRegOff spReg (sp0 - wORD_SIZE dflags - sp_off) {- Note [SP old/young offsets] diff --git a/compiler/cmm/Debug.hs b/compiler/cmm/Debug.hs index 044a00009c..da37495530 100644 --- a/compiler/cmm/Debug.hs +++ b/compiler/cmm/Debug.hs @@ -349,8 +349,8 @@ in addition to the usual beginning-of-block statement, unwind Sp = Just Sp + 0; I64[Sp - 8] = c2dD; R1 = v :: P64; - unwind Sp = Just Sp + 8; Sp = Sp - 8; + unwind Sp = Just Sp + 8; if (R1 & 7 != 0) goto c2dD; else goto c2dE; The remaining blocks are simple, @@ -392,10 +392,95 @@ The flow of unwinding information through the compiler is a bit convoluted: * This unwind information is converted to DebugBlocks by Debug.cmmDebugGen - * These DebugBlcosk are then converted to, e.g., DWARF unwinding tables + * These DebugBlocks are then converted to, e.g., DWARF unwinding tables (by the Dwarf module) and emitted in the final object. -See also: Note [Unwinding information in the NCG] in AsmCodeGen. +See also: + Note [Unwinding information in the NCG] in AsmCodeGen, + Note [Unwind pseudo-instruction in Cmm], + Note [Debugging DWARF unwinding info]. + + +Note [Debugging DWARF unwinding info] +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +For debugging generated unwinding info I've found it most useful to dump the +disassembled binary with objdump -D and dump the debug info with +readelf --debug-dump=frames-interp. + +You should get something like this: + + 0000000000000010 <stg_catch_frame_info>: + 10: 48 83 c5 18 add $0x18,%rbp + 14: ff 65 00 jmpq *0x0(%rbp) + +and: + + Contents of the .debug_frame section: + + 00000000 0000000000000014 ffffffff CIE "" cf=1 df=-8 ra=16 + LOC CFA rbp rsp ra + 0000000000000000 rbp+0 v+0 s c+0 + + 00000018 0000000000000024 00000000 FDE cie=00000000 pc=000000000000000f..0000000000000017 + LOC CFA rbp rsp ra + 000000000000000f rbp+0 v+0 s c+0 + 000000000000000f rbp+24 v+0 s c+0 + +To read it http://www.dwarfstd.org/doc/dwarf-2.0.0.pdf has a nice example in +Appendix 5 (page 101 of the pdf) and more details in the relevant section. + +The key thing to keep in mind is that the value at LOC is the value from +*before* the instruction at LOC executes. In other words it answers the +question: if my $rip is at LOC, how do I get the relevant values given the +values obtained through unwinding so far. + +If the readelf --debug-dump=frames-interp output looks wrong, it may also be +useful to look at readelf --debug-dump=frames, which is closer to the +information that GHC generated. + +It's also useful to dump the relevant Cmm with -ddump-cmm -ddump-opt-cmm +-ddump-cmm-proc -ddump-cmm-verbose. Note [Unwind pseudo-instruction in Cmm] +explains how to interpret it. + +Inside gdb there are a couple useful commands for inspecting frames. +For example: + + gdb> info frame <num> + +It shows the values of registers obtained through unwinding. + +Another useful thing to try when debugging the DWARF unwinding is to enable +extra debugging output in GDB: + + gdb> set debug frame 1 + +This makes GDB produce a trace of its internal workings. Having gone this far, +it's just a tiny step to run GDB in GDB. Make sure you install debugging +symbols for gdb if you obtain it through a package manager. + +Keep in mind that the current release of GDB has an instruction pointer handling +heuristic that works well for C-like languages, but doesn't always work for +Haskell. See Note [Info Offset] in Dwarf.Types for more details. + +Note [Unwind pseudo-instruction in Cmm] +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +One of the possible CmmNodes is a CmmUnwind pseudo-instruction. It doesn't +generate any assembly, but controls what DWARF unwinding information gets +generated. + +It's important to understand what ranges of code the unwind pseudo-instruction +refers to. +For a sequence of CmmNodes like: + + A // starts at addr X and ends at addr Y-1 + unwind Sp = Just Sp + 16; + B // starts at addr Y and ends at addr Z + +the unwind statement reflects the state after A has executed, but before B +has executed. If you consult the Note [Debugging DWARF unwinding info], the +LOC this information will end up in is Y. -} -- | A label associated with an 'UnwindTable' diff --git a/compiler/nativeGen/Dwarf/Types.hs b/compiler/nativeGen/Dwarf/Types.hs index 579ed0d256..25629448dd 100644 --- a/compiler/nativeGen/Dwarf/Types.hs +++ b/compiler/nativeGen/Dwarf/Types.hs @@ -415,6 +415,12 @@ pprFrameBlock (DwarfFrameBlock hasInfo uws0) = -- Note that this will not prevent GDB from failing to look-up the -- correct function name for the frame, as that uses the symbol table, -- which we can not manipulate as easily. +-- +-- 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. +-- +-- [1] https://sourceware.org/ml/gdb-patches/2018-02/msg00055.html -- | Get DWARF register ID for a given GlobalReg dwarfGlobalRegNo :: Platform -> GlobalReg -> Word8 diff --git a/rts/Exception.cmm b/rts/Exception.cmm index 96d95e6f8c..8deecbb1e8 100644 --- a/rts/Exception.cmm +++ b/rts/Exception.cmm @@ -370,7 +370,6 @@ INFO_TABLE_RET(stg_catch_frame, CATCH_FRAME, exceptions_blocked,handler)) return (P_ ret) { - unwind Sp = Sp + SIZEOF_StgCatchFrame; return (ret); } diff --git a/testsuite/driver/testglobals.py b/testsuite/driver/testglobals.py index f6831c9ad8..246f26ce9a 100644 --- a/testsuite/driver/testglobals.py +++ b/testsuite/driver/testglobals.py @@ -105,6 +105,12 @@ class TestConfig: # Do we have SMP support? self.have_smp = False + # Is gdb avaliable? + self.have_gdb = False + + # Is readelf available? + self.have_readelf = False + # Are we testing an in-tree compiler? self.in_tree_compiler = True diff --git a/testsuite/driver/testlib.py b/testsuite/driver/testlib.py index f2bb1c9f01..3bae76585a 100644 --- a/testsuite/driver/testlib.py +++ b/testsuite/driver/testlib.py @@ -413,6 +413,12 @@ def compiler_profiled( ): def compiler_debugged( ): return config.compiler_debugged +def have_gdb( ): + return config.have_gdb + +def have_readelf( ): + return config.have_readelf + # --- def high_memory_usage(name, opts): diff --git a/testsuite/mk/test.mk b/testsuite/mk/test.mk index 1eb8d49c4b..87d22b330b 100644 --- a/testsuite/mk/test.mk +++ b/testsuite/mk/test.mk @@ -90,6 +90,8 @@ GHC_PRIM_LIBDIR := $(subst library-dirs: ,,$(shell "$(GHC_PKG)" field ghc-prim l HAVE_VANILLA := $(shell if [ -f $(subst \,/,$(GHC_PRIM_LIBDIR))/GHC/PrimopWrappers.hi ]; then echo YES; else echo NO; fi) HAVE_DYNAMIC := $(shell if [ -f $(subst \,/,$(GHC_PRIM_LIBDIR))/GHC/PrimopWrappers.dyn_hi ]; then echo YES; else echo NO; fi) HAVE_PROFILING := $(shell if [ -f $(subst \,/,$(GHC_PRIM_LIBDIR))/GHC/PrimopWrappers.p_hi ]; then echo YES; else echo NO; fi) +HAVE_GDB := $(shell if gdb --version > /dev/null 2> /dev/null; then echo YES; else echo NO; fi) +HAVE_READELF := $(shell if readelf --version > /dev/null 2> /dev/null; then echo YES; else echo NO; fi) ifeq "$(HAVE_VANILLA)" "YES" RUNTEST_OPTS += -e config.have_vanilla=True @@ -135,6 +137,18 @@ else RUNTEST_OPTS += -e config.unregisterised=False endif +ifeq "$(HAVE_GDB)" "YES" +RUNTEST_OPTS += -e config.have_gdb=True +else +RUNTEST_OPTS += -e config.have_gdb=False +endif + +ifeq "$(HAVE_READELF)" "YES" +RUNTEST_OPTS += -e config.have_readelf=True +else +RUNTEST_OPTS += -e config.have_readelf=False +endif + ifeq "$(GhcDynamicByDefault)" "YES" RUNTEST_OPTS += -e config.ghc_dynamic_by_default=True CABAL_MINIMAL_BUILD = --enable-shared --disable-library-vanilla diff --git a/testsuite/tests/codeGen/should_compile/Makefile b/testsuite/tests/codeGen/should_compile/Makefile index a8414384cf..e024788085 100644 --- a/testsuite/tests/codeGen/should_compile/Makefile +++ b/testsuite/tests/codeGen/should_compile/Makefile @@ -33,3 +33,8 @@ debug: ./debug rm debug + +T14999: + '$(TEST_HC)' $(TEST_HC_OPTS) -O2 -g -c T14999.cmm -o T14999.o + gdb --batch -ex 'file T14999.o' -ex 'disassemble stg_catch_frame_info' --nx | tr -s '[:blank:]' + readelf --debug-dump=frames-interp T14999.o | tr -s '[:blank:]' diff --git a/testsuite/tests/codeGen/should_compile/T14999.cmm b/testsuite/tests/codeGen/should_compile/T14999.cmm new file mode 100644 index 0000000000..a3e283b0be --- /dev/null +++ b/testsuite/tests/codeGen/should_compile/T14999.cmm @@ -0,0 +1,11 @@ +#define CATCH_FRAME 34 + +#define SIZEOF_StgCatchFrame (SIZEOF_StgHeader+16) + +INFO_TABLE_RET(stg_catch_frame, CATCH_FRAME, + bits64 info_ptr, bits64 exceptions_blocked, gcptr handler) + return (gcptr ret) +{ + return (ret); +} + diff --git a/testsuite/tests/codeGen/should_compile/T14999.stdout b/testsuite/tests/codeGen/should_compile/T14999.stdout new file mode 100644 index 0000000000..4bca980a9a --- /dev/null +++ b/testsuite/tests/codeGen/should_compile/T14999.stdout @@ -0,0 +1,16 @@ +Dump of assembler code for function stg_catch_frame_info: + 0x0000000000000010 <+0>: add $0x18,%rbp + 0x0000000000000014 <+4>: jmpq *0x0(%rbp) +End of assembler dump. +Contents of the .debug_frame section: + +00000000 0000000000000014 ffffffff CIE "" cf=1 df=-8 ra=16 + LOC CFA rbp rsp ra +0000000000000000 rbp+0 v+0 s c+0 + +00000018 000000000000002c 00000000 FDE cie=00000000 pc=000000000000000f..0000000000000017 + LOC CFA rbp rsp ra +000000000000000f rbp+0 v+0 s c+0 +000000000000000f rbp+24 v+0 s c+0 +0000000000000014 rbp+0 v+0 s c+0 + diff --git a/testsuite/tests/codeGen/should_compile/all.T b/testsuite/tests/codeGen/should_compile/all.T index fb813a497a..9118b6c23b 100644 --- a/testsuite/tests/codeGen/should_compile/all.T +++ b/testsuite/tests/codeGen/should_compile/all.T @@ -38,3 +38,8 @@ test('T12355', normal, compile, ['']) test('T14626', normal, run_command, ['$MAKE -s --no-print-directory T14626']) +test('T14999', + [when((arch('powerpc64') or arch('powerpc64le')), expect_broken(11261)), + unless(opsys('linux') and arch('x86_64') and have_gdb() and + have_readelf(), skip)], + run_command, ['$MAKE -s --no-print-directory T14999']) |