CbC/CbC_gcc: gcc/config/xtensa/unwind-dw2-xtensa.c comparison

comparison gcc/config/xtensa/unwind-dw2-xtensa.c @ 0:a06113de4d67

first commit

author	kent <kent@cr.ie.u-ryukyu.ac.jp>
date	Fri, 17 Jul 2009 14:47:48 +0900
parents
children	77e2b8dfacca

comparison

equal deleted inserted replaced

--1:000000000000
+:a06113de4d67
+/* DWARF2 exception handling and frame unwinding for Xtensa.
+Copyright (C) 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006,
+2007, 2008, 2009
+Free Software Foundation, Inc.
+This file is part of GCC.
+GCC is free software; you can redistribute it and/or modify it
+under the terms of the GNU General Public License as published by
+the Free Software Foundation; either version 3, or (at your option)
+any later version.
+GCC is distributed in the hope that it will be useful, but WITHOUT
+ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public
+License for more details.
+Under Section 7 of GPL version 3, you are granted additional
+permissions described in the GCC Runtime Library Exception, version
+3.1, as published by the Free Software Foundation.
+You should have received a copy of the GNU General Public License and
+a copy of the GCC Runtime Library Exception along with this program;
+see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
+<http://www.gnu.org/licenses/>.  */
+#include "tconfig.h"
+#include "tsystem.h"
+#include "coretypes.h"
+#include "tm.h"
+#include "dwarf2.h"
+#include "unwind.h"
+#ifdef __USING_SJLJ_EXCEPTIONS__
+# define NO_SIZE_OF_ENCODED_VALUE
+#endif
+#include "unwind-pe.h"
+#include "unwind-dw2-fde.h"
+#include "unwind-dw2-xtensa.h"
+#ifndef __USING_SJLJ_EXCEPTIONS__
+/* The standard CIE and FDE structures work fine for Xtensa but the
+variable-size register window save areas are not a good fit for the rest
+of the standard DWARF unwinding mechanism.  Nor is that mechanism
+necessary, since the register save areas are always in fixed locations
+in each stack frame.  This file is a stripped down and customized version
+of the standard DWARF unwinding code.  It needs to be customized to have
+builtin logic for finding the save areas and also to track the stack
+pointer value (besides the CFA) while unwinding since the primary save
+area is located below the stack pointer.  It is stripped down to reduce
+code size and ease the maintenance burden of tracking changes in the
+standard version of the code.  */
+#ifndef DWARF_REG_TO_UNWIND_COLUMN
+#define DWARF_REG_TO_UNWIND_COLUMN(REGNO) (REGNO)
+#endif
+#define XTENSA_RA_FIELD_MASK 0x3FFFFFFF
+/* This is the register and unwind state for a particular frame.  This
+provides the information necessary to unwind up past a frame and return
+to its caller.  */
+struct _Unwind_Context
+{
+/* Track register window save areas of 4 registers each, instead of
+keeping separate addresses for the individual registers.  */
+_Unwind_Word *reg[4];
+void *cfa;
+void *sp;
+void *ra;
+/* Cache the 2 high bits to replace the window size in return addresses.  */
+_Unwind_Word ra_high_bits;
+void *lsda;
+struct dwarf_eh_bases bases;
+/* Signal frame context.  */
+#define SIGNAL_FRAME_BIT ((~(_Unwind_Word) 0 >> 1) + 1)
+_Unwind_Word flags;
+/* 0 for now, can be increased when further fields are added to
+struct _Unwind_Context.  */
+_Unwind_Word version;
+};
+/* Read unaligned data from the instruction buffer.  */
+union unaligned
+{
+void *p;
+} __attribute__ ((packed));
+static void uw_update_context (struct _Unwind_Context *, _Unwind_FrameState *);
+static _Unwind_Reason_Code uw_frame_state_for (struct _Unwind_Context *,
+					       _Unwind_FrameState *);
+static inline void *
+read_pointer (const void *p) { const union unaligned *up = p; return up->p; }
+static inline _Unwind_Word
+_Unwind_IsSignalFrame (struct _Unwind_Context *context)
+{
+return (context->flags & SIGNAL_FRAME_BIT) ? 1 : 0;
+}
+static inline void
+_Unwind_SetSignalFrame (struct _Unwind_Context *context, int val)
+{
+if (val)
+context->flags |= SIGNAL_FRAME_BIT;
+else
+context->flags &= ~SIGNAL_FRAME_BIT;
+}
+/* Get the value of register INDEX as saved in CONTEXT.  */
+inline _Unwind_Word
+_Unwind_GetGR (struct _Unwind_Context *context, int index)
+{
+_Unwind_Word *ptr;
+index = DWARF_REG_TO_UNWIND_COLUMN (index);
+ptr = context->reg[index >> 2] + (index & 3);
+return *ptr;
+}
+/* Get the value of the CFA as saved in CONTEXT.  */
+_Unwind_Word
+_Unwind_GetCFA (struct _Unwind_Context *context)
+{
+return (_Unwind_Ptr) context->cfa;
+}
+/* Overwrite the saved value for register INDEX in CONTEXT with VAL.  */
+inline void
+_Unwind_SetGR (struct _Unwind_Context *context, int index, _Unwind_Word val)
+{
+_Unwind_Word *ptr;
+index = DWARF_REG_TO_UNWIND_COLUMN (index);
+ptr = context->reg[index >> 2] + (index & 3);
+*ptr = val;
+}
+/* Retrieve the return address for CONTEXT.  */
+inline _Unwind_Ptr
+_Unwind_GetIP (struct _Unwind_Context *context)
+{
+return (_Unwind_Ptr) context->ra;
+}
+/* Retrieve the return address and flag whether that IP is before
+or after first not yet fully executed instruction.  */
+inline _Unwind_Ptr
+_Unwind_GetIPInfo (struct _Unwind_Context *context, int *ip_before_insn)
+{
+*ip_before_insn = _Unwind_IsSignalFrame (context);
+return (_Unwind_Ptr) context->ra;
+}
+/* Overwrite the return address for CONTEXT with VAL.  */
+inline void
+_Unwind_SetIP (struct _Unwind_Context *context, _Unwind_Ptr val)
+{
+context->ra = (void *) val;
+}
+void *
+_Unwind_GetLanguageSpecificData (struct _Unwind_Context *context)
+{
+return context->lsda;
+}
+_Unwind_Ptr
+_Unwind_GetRegionStart (struct _Unwind_Context *context)
+{
+return (_Unwind_Ptr) context->bases.func;
+}
+void *
+_Unwind_FindEnclosingFunction (void *pc)
+{
+struct dwarf_eh_bases bases;
+const struct dwarf_fde *fde = _Unwind_Find_FDE (pc-1, &bases);
+if (fde)
+return bases.func;
+else
+return NULL;
+}
+_Unwind_Ptr
+_Unwind_GetDataRelBase (struct _Unwind_Context *context)
+{
+return (_Unwind_Ptr) context->bases.dbase;
+}
+_Unwind_Ptr
+_Unwind_GetTextRelBase (struct _Unwind_Context *context)
+{
+return (_Unwind_Ptr) context->bases.tbase;
+}
+#ifdef MD_UNWIND_SUPPORT
+#include MD_UNWIND_SUPPORT
+#endif
+/* Extract any interesting information from the CIE for the translation
+unit F belongs to.  Return a pointer to the byte after the augmentation,
+or NULL if we encountered an undecipherable augmentation.  */
+static const unsigned char *
+extract_cie_info (const struct dwarf_cie *cie, struct _Unwind_Context *context,
+		  _Unwind_FrameState *fs)
+{
+const unsigned char *aug = cie->augmentation;
+const unsigned char *p = aug + strlen ((const char *)aug) + 1;
+const unsigned char *ret = NULL;
+_uleb128_t utmp;
+_sleb128_t stmp;
+/* g++ v2 "eh" has pointer immediately following augmentation string,
+so it must be handled first.  */
+if (aug[0] == 'e' && aug[1] == 'h')
+{
+fs->eh_ptr = read_pointer (p);
+p += sizeof (void *);
+aug += 2;
+}
+/* Immediately following the augmentation are the code and
+data alignment and return address column.  */
+p = read_uleb128 (p, &utmp);
+p = read_sleb128 (p, &stmp);
+if (cie->version == 1)
+fs->retaddr_column = *p++;
+else
+{
+p = read_uleb128 (p, &utmp);
+fs->retaddr_column = (_Unwind_Word)utmp;
+}
+fs->lsda_encoding = DW_EH_PE_omit;
+/* If the augmentation starts with 'z', then a uleb128 immediately
+follows containing the length of the augmentation field following
+the size.  */
+if (*aug == 'z')
+{
+p = read_uleb128 (p, &utmp);
+ret = p + utmp;
+fs->saw_z = 1;
+++aug;
+}
+/* Iterate over recognized augmentation subsequences.  */
+while (*aug != '\0')
+{
+/* "L" indicates a byte showing how the LSDA pointer is encoded.  */
+if (aug[0] == 'L')
+	{
+	  fs->lsda_encoding = *p++;
+	  aug += 1;
+	}
+/* "R" indicates a byte indicating how FDE addresses are encoded.  */
+else if (aug[0] == 'R')
+	{
+	  fs->fde_encoding = *p++;
+	  aug += 1;
+	}
+/* "P" indicates a personality routine in the CIE augmentation.  */
+else if (aug[0] == 'P')
+	{
+	  _Unwind_Ptr personality;
+	  p = read_encoded_value (context, *p, p + 1, &personality);
+	  fs->personality = (_Unwind_Personality_Fn) personality;
+	  aug += 1;
+	}
+/* "S" indicates a signal frame.  */
+else if (aug[0] == 'S')
+	{
+	  fs->signal_frame = 1;
+	  aug += 1;
+	}
+/* Otherwise we have an unknown augmentation string.
+	 Bail unless we saw a 'z' prefix.  */
+else
+	return ret;
+}
+return ret ? ret : p;
+}
+/* Given the _Unwind_Context CONTEXT for a stack frame, look up the FDE for
+its caller and decode it into FS.  This function also sets the
+lsda member of CONTEXT, as it is really information
+about the caller's frame.  */
+static _Unwind_Reason_Code
+uw_frame_state_for (struct _Unwind_Context *context, _Unwind_FrameState *fs)
+{
+const struct dwarf_fde *fde;
+const struct dwarf_cie *cie;
+const unsigned char *aug;
+int window_size;
+_Unwind_Word *ra_ptr;
+memset (fs, 0, sizeof (*fs));
+context->lsda = 0;
+fde = _Unwind_Find_FDE (context->ra + _Unwind_IsSignalFrame (context) - 1,
+			  &context->bases);
+if (fde == NULL)
+{
+#ifdef MD_FALLBACK_FRAME_STATE_FOR
+_Unwind_Reason_Code reason;
+/* Couldn't find frame unwind info for this function.  Try a
+	 target-specific fallback mechanism.  This will necessarily
+	 not provide a personality routine or LSDA.  */
+reason = MD_FALLBACK_FRAME_STATE_FOR (context, fs);
+if (reason != _URC_END_OF_STACK)
+	return reason;
+#endif
+/* The frame was not recognized and handled by the fallback function,
+	 but it is not really the end of the stack.  Fall through here and
+	 unwind it anyway.  */
+}
+else
+{
+cie = get_cie (fde);
+if (extract_cie_info (cie, context, fs) == NULL)
+	/* CIE contained unknown augmentation.  */
+	return _URC_FATAL_PHASE1_ERROR;
+/* Locate augmentation for the fde.  */
+aug = (const unsigned char *) fde + sizeof (*fde);
+aug += 2 * size_of_encoded_value (fs->fde_encoding);
+if (fs->saw_z)
+	{
+	  _uleb128_t i;
+	  aug = read_uleb128 (aug, &i);
+	}
+if (fs->lsda_encoding != DW_EH_PE_omit)
+	{
+	  _Unwind_Ptr lsda;
+	  aug = read_encoded_value (context, fs->lsda_encoding, aug, &lsda);
+	  context->lsda = (void *) lsda;
+	}
+}
+/* Check for the end of the stack.  This needs to be checked after
+the MD_FALLBACK_FRAME_STATE_FOR check for signal frames because
+the contents of context->reg[0] are undefined at a signal frame,
+and register a0 may appear to be zero.  (The return address in
+context->ra comes from register a4 or a8).  */
+ra_ptr = context->reg[0];
+if (ra_ptr && *ra_ptr == 0)
+return _URC_END_OF_STACK;
+/* Find the window size from the high bits of the return address.  */
+if (ra_ptr)
+window_size = (*ra_ptr >> 30) * 4;
+else
+window_size = 8;
+fs->retaddr_column = window_size;
+return _URC_NO_REASON;
+}
+static void
+uw_update_context_1 (struct _Unwind_Context *context, _Unwind_FrameState *fs)
+{
+struct _Unwind_Context orig_context = *context;
+_Unwind_Word *sp, *cfa, *next_cfa;
+int i;
+if (fs->signal_regs)
+{
+cfa = (_Unwind_Word *) fs->signal_regs[1];
+next_cfa = (_Unwind_Word *) cfa[-3];
+for (i = 0; i < 4; i++)
+	context->reg[i] = fs->signal_regs + (i << 2);
+}
+else
+{
+int window_size = fs->retaddr_column >> 2;
+sp = (_Unwind_Word *) orig_context.sp;
+cfa = (_Unwind_Word *) orig_context.cfa;
+next_cfa = (_Unwind_Word *) cfa[-3];
+/* Registers a0-a3 are in the save area below sp.  */
+context->reg[0] = sp - 4;
+/* Find the extra save area below next_cfa.  */
+for (i = 1; i < window_size; i++)
+	context->reg[i] = next_cfa - 4 * (1 + window_size - i);
+/* Remaining registers rotate from previous save areas.  */
+for (i = window_size; i < 4; i++)
+	context->reg[i] = orig_context.reg[i - window_size];
+}
+context->sp = cfa;
+context->cfa = next_cfa;
+_Unwind_SetSignalFrame (context, fs->signal_frame);
+}
+/* CONTEXT describes the unwind state for a frame, and FS describes the FDE
+of its caller.  Update CONTEXT to refer to the caller as well.  Note
+that the lsda member is not updated here, but later in
+uw_frame_state_for.  */
+static void
+uw_update_context (struct _Unwind_Context *context, _Unwind_FrameState *fs)
+{
+uw_update_context_1 (context, fs);
+/* Compute the return address now, since the return address column
+can change from frame to frame.  */
+if (fs->signal_ra != 0)
+context->ra = (void *) fs->signal_ra;
+else
+context->ra = (void *) ((_Unwind_GetGR (context, fs->retaddr_column)
+			     & XTENSA_RA_FIELD_MASK) | context->ra_high_bits);
+}
+static void
+uw_advance_context (struct _Unwind_Context *context, _Unwind_FrameState *fs)
+{
+uw_update_context (context, fs);
+}
+/* Fill in CONTEXT for top-of-stack.  The only valid registers at this
+level will be the return address and the CFA.  */
+#define uw_init_context(CONTEXT)					   \
+do									   \
+{									   \
+__builtin_unwind_init ();						   \
+uw_init_context_1 (CONTEXT, __builtin_dwarf_cfa (),		   \
+			 __builtin_return_address (0));			   \
+}									   \
+while (0)
+static void
+uw_init_context_1 (struct _Unwind_Context *context, void *outer_cfa,
+		   void *outer_ra)
+{
+void *ra = __builtin_return_address (0);
+void *cfa = __builtin_dwarf_cfa ();
+_Unwind_FrameState fs;
+memset (context, 0, sizeof (struct _Unwind_Context));
+context->ra = ra;
+memset (&fs, 0, sizeof (fs));
+fs.retaddr_column = 8;
+context->sp = cfa;
+context->cfa = outer_cfa;
+context->ra_high_bits =
+((_Unwind_Word) uw_init_context_1) & ~XTENSA_RA_FIELD_MASK;
+uw_update_context_1 (context, &fs);
+context->ra = outer_ra;
+}
+/* Install TARGET into CURRENT so that we can return to it.  This is a
+macro because __builtin_eh_return must be invoked in the context of
+our caller.  */
+#define uw_install_context(CURRENT, TARGET)				 \
+do									 \
+{									 \
+long offset = uw_install_context_1 ((CURRENT), (TARGET));		 \
+void *handler = __builtin_frob_return_addr ((TARGET)->ra);	 \
+__builtin_eh_return (offset, handler);				 \
+}									 \
+while (0)
+static long
+uw_install_context_1 (struct _Unwind_Context *current,
+		      struct _Unwind_Context *target)
+{
+long i;
+/* The eh_return insn assumes a window size of 8, so don't bother copying
+the save areas for registers a8-a15 since they won't be reloaded.  */
+for (i = 0; i < 2; ++i)
+{
+void *c = current->reg[i];
+void *t = target->reg[i];
+if (t && c && t != c)
+	memcpy (c, t, 4 * sizeof (_Unwind_Word));
+}
+return 0;
+}
+static inline _Unwind_Ptr
+uw_identify_context (struct _Unwind_Context *context)
+{
+return _Unwind_GetCFA (context);
+}
+#include "unwind.inc"
+#if defined (USE_GAS_SYMVER) && defined (SHARED) && defined (USE_LIBUNWIND_EXCEPTIONS)
+alias (_Unwind_Backtrace);
+alias (_Unwind_DeleteException);
+alias (_Unwind_FindEnclosingFunction);
+alias (_Unwind_ForcedUnwind);
+alias (_Unwind_GetDataRelBase);
+alias (_Unwind_GetTextRelBase);
+alias (_Unwind_GetCFA);
+alias (_Unwind_GetGR);
+alias (_Unwind_GetIP);
+alias (_Unwind_GetLanguageSpecificData);
+alias (_Unwind_GetRegionStart);
+alias (_Unwind_RaiseException);
+alias (_Unwind_Resume);
+alias (_Unwind_Resume_or_Rethrow);
+alias (_Unwind_SetGR);
+alias (_Unwind_SetIP);
+#endif
+#endif /* !USING_SJLJ_EXCEPTIONS */

Mercurial > hg > CbC > CbC_gcc

comparison gcc/config/xtensa/unwind-dw2-xtensa.c @ 0:a06113de4d67