Frame Descriptors. */
struct cie_unit
{
- /* Offset of this unit in dwarf_frame_buffer. */
+ /* Offset of this unit in .debug_frame or .eh_frame. */
ULONGEST offset;
/* A null-terminated string that identifies the augmentation to this CIE or
struct objfile *objfile;
};
+enum ptr_encoding {
+ PE_absptr = DW_EH_PE_absptr,
+ PE_pcrel = DW_EH_PE_pcrel,
+ PE_textrel = DW_EH_PE_textrel,
+ PE_datarel = DW_EH_PE_datarel,
+ PE_funcrel = DW_EH_PE_funcrel
+};
+
#define UNWIND_CONTEXT(fi) ((struct context *) (fi->context))
\f
extern unsigned int dwarf_frame_size;
extern file_ptr dwarf_eh_frame_offset;
extern unsigned int dwarf_eh_frame_size;
-
-static char *dwarf_frame_buffer;
\f
extern char *dwarf2_read_section (struct objfile *objfile, file_ptr offset,
static CORE_ADDR read_pointer (bfd * abfd, char **p);
static CORE_ADDR read_encoded_pointer (bfd * abfd, char **p,
unsigned char encoding);
+static enum ptr_encoding pointer_encoding (unsigned char encoding);
static LONGEST read_initial_length (bfd * abfd, char *buf, int *bytes_read);
static ULONGEST read_length (bfd * abfd, char *buf, int *bytes_read,
}
}
+/* This functions only reads appropriate amount of data from *p
+ * and returns the resulting value. Calling function must handle
+ * different encoding possibilities itself! */
static CORE_ADDR
read_encoded_pointer (bfd * abfd, char **p, unsigned char encoding)
{
"read_encoded_pointer: unknown pointer encoding");
}
- if (ret != 0)
- switch (encoding & 0xf0)
- {
- case DW_EH_PE_absptr:
- break;
- case DW_EH_PE_pcrel:
- ret += (CORE_ADDR) * p;
- break;
- case DW_EH_PE_textrel:
- case DW_EH_PE_datarel:
- case DW_EH_PE_funcrel:
- default:
- internal_error (__FILE__, __LINE__,
- "read_encoded_pointer: unknown pointer encoding");
- }
+ return ret;
+}
+
+/* Variable 'encoding' carries 3 different flags:
+ * - encoding & 0x0f : size of the address (handled in read_encoded_pointer())
+ * - encoding & 0x70 : type (absolute, relative, ...)
+ * - encoding & 0x80 : indirect flag (DW_EH_PE_indirect == 0x80). */
+enum ptr_encoding
+pointer_encoding (unsigned char encoding)
+{
+ int ret;
+ if (encoding & DW_EH_PE_indirect)
+ warning ("CFI: Unsupported pointer encoding: DW_EH_PE_indirect");
+
+ switch (encoding & 0x70)
+ {
+ case DW_EH_PE_absptr:
+ case DW_EH_PE_pcrel:
+ case DW_EH_PE_textrel:
+ case DW_EH_PE_datarel:
+ case DW_EH_PE_funcrel:
+ ret = encoding & 0x70;
+ break;
+ default:
+ internal_error (__FILE__, __LINE__,
+ "CFI: unknown pointer encoding");
+ }
return ret;
}
case DW_CFA_set_loc:
fs->pc = read_encoded_pointer (objfile->obfd, &insn_ptr,
fs->addr_encoding);
+
+ if (pointer_encoding (fs->addr_encoding) != PE_absptr)
+ warning ("CFI: DW_CFA_set_loc uses relative addressing");
+
break;
case DW_CFA_advance_loc1:
}
/* Build the cie_chunks and fde_chunks tables from informations
- in .debug_frame section. */
-void
-dwarf2_build_frame_info (struct objfile *objfile)
+ found in .debug_frame and .eh_frame sections. */
+/* We can handle both of these sections almost in the same way, however there
+ are some exceptions:
+ - CIE ID is -1 in debug_frame, but 0 in eh_frame
+ - eh_frame may contain some more information that are used only by gcc
+ (eg. personality pointer, LSDA pointer, ...). Most of them we can ignore.
+ - In debug_frame FDE's item cie_id contains offset of it's parent CIE.
+ In eh_frame FDE's item cie_id is a relative pointer to the parent CIE.
+ Anyway we don't need to bother with this, because we are smart enough
+ to keep the pointer to the parent CIE of oncomming FDEs in 'last_cie'.
+ - Although debug_frame items can contain Augmentation as well as
+ eh_frame ones, I have never seen them non-empty. Thus only in eh_frame
+ we can encounter for example non-absolute pointers (Aug. 'R').
+ -- mludvig */
+static void
+parse_frame_info (struct objfile *objfile, file_ptr frame_offset,
+ unsigned int frame_size, int eh_frame)
{
bfd *abfd = objfile->obfd;
+ asection *curr_section_ptr;
char *start = NULL;
char *end = NULL;
- int from_eh = 0;
+ char *frame_buffer = NULL;
+ char *curr_section_name, *aug_data;
+ struct cie_unit *last_cie = NULL;
+ int last_dup_fde = 0;
+ int aug_len, i;
+ CORE_ADDR curr_section_vma = 0;
unwind_tmp_obstack_init ();
- dwarf_frame_buffer = 0;
+ frame_buffer = dwarf2_read_section (objfile, frame_offset, frame_size);
- if (dwarf_frame_offset)
- {
- dwarf_frame_buffer = dwarf2_read_section (objfile,
- dwarf_frame_offset,
- dwarf_frame_size);
+ start = frame_buffer;
+ end = frame_buffer + frame_size;
- start = dwarf_frame_buffer;
- end = dwarf_frame_buffer + dwarf_frame_size;
- }
- else if (dwarf_eh_frame_offset)
- {
- dwarf_frame_buffer = dwarf2_read_section (objfile,
- dwarf_eh_frame_offset,
- dwarf_eh_frame_size);
-
- start = dwarf_frame_buffer;
- end = dwarf_frame_buffer + dwarf_eh_frame_size;
-
- from_eh = 1;
- }
+ curr_section_name = eh_frame ? ".eh_frame" : ".debug_frame";
+ curr_section_ptr = bfd_get_section_by_name (abfd, curr_section_name);
+ if (curr_section_ptr)
+ curr_section_vma = curr_section_ptr->vma;
if (start)
{
{
unsigned long length;
ULONGEST cie_id;
- ULONGEST unit_offset = start - dwarf_frame_buffer;
- int bytes_read;
- int dwarf64;
+ ULONGEST unit_offset = start - frame_buffer;
+ int bytes_read, dwarf64, flag_pcrel;
char *block_end;
length = read_initial_length (abfd, start, &bytes_read);
dwarf64 = (bytes_read == 12);
block_end = start + length;
+ if (length == 0)
+ {
+ start = block_end;
+ continue;
+ }
+
cie_id = read_length (abfd, start, &bytes_read, dwarf64);
start += bytes_read;
- if ((from_eh && cie_id == 0) || is_cie (cie_id, dwarf64))
+ if ((eh_frame && cie_id == 0) || is_cie (cie_id, dwarf64))
{
struct cie_unit *cie = cie_unit_alloc ();
char *aug;
start++; /* version */
cie->augmentation = aug = start;
- while (*start)
- start++;
- start++; /* skip past NUL */
+ while (*start++); /* Skips last NULL as well */
cie->code_align = read_uleb128 (abfd, &start);
cie->data_align = read_sleb128 (abfd, &start);
cie->ra = read_1u (abfd, &start);
+ /* Augmentation:
+ z Indicates that a uleb128 is present to size the
+ augmentation section.
+ L Indicates the encoding (and thus presence) of
+ an LSDA pointer in the FDE augmentation.
+ R Indicates a non-default pointer encoding for
+ FDE code pointers.
+ P Indicates the presence of an encoding + language
+ personality routine in the CIE augmentation.
+
+ [This info comes from GCC's dwarf2out.c]
+ */
if (*aug == 'z')
{
- int xtra = read_uleb128 (abfd, &start);
- start += xtra;
+ aug_len = read_uleb128 (abfd, &start);
+ aug_data = start;
+ start += aug_len;
++aug;
}
+ cie->data = start;
+ cie->data_length = block_end - cie->data;
+
while (*aug != '\0')
{
if (aug[0] == 'e' && aug[1] == 'h')
{
- start += sizeof (void *);
- aug += 2;
+ aug_data += sizeof (void *);
+ aug++;
}
else if (aug[0] == 'R')
+ cie->addr_encoding = *aug_data++;
+ else if (aug[0] == 'P')
{
- cie->addr_encoding = *start++;
- aug += 1;
+ CORE_ADDR pers_addr;
+ int pers_addr_enc;
+
+ pers_addr_enc = *aug_data++;
+ /* We don't need pers_addr value and so we
+ don't care about it's encoding. */
+ pers_addr = read_encoded_pointer (abfd, &aug_data,
+ pers_addr_enc);
}
- else if (aug[0] == 'P')
+ else if (aug[0] == 'L' && eh_frame)
{
- CORE_ADDR ptr;
- ptr = read_encoded_pointer (abfd, &start,
- cie->addr_encoding);
- aug += 1;
+ int lsda_addr_enc;
+
+ /* Perhaps we should save this to CIE for later use?
+ Do we need it for something in GDB? */
+ lsda_addr_enc = *aug_data++;
}
else
- warning ("%s(): unknown augmentation", __func__);
+ warning ("CFI warning: unknown augmentation \"%c\""
+ " in \"%s\" of\n"
+ "\t%s", aug[0], curr_section_name,
+ objfile->name);
+ aug++;
}
- cie->data = start;
- cie->data_length = block_end - start;
+ last_cie = cie;
}
else
{
struct fde_unit *fde;
struct cie_unit *cie;
+ int dup = 0;
+ CORE_ADDR init_loc;
+
+ /* We assume that debug_frame is in order
+ CIE,FDE,CIE,FDE,FDE,... and thus the CIE for this FDE
+ should be stored in last_cie pointer. If not, we'll
+ try to find it by the older way. */
+ if (last_cie)
+ cie = last_cie;
+ else
+ {
+ warning ("CFI: last_cie == NULL. "
+ "Perhaps a malformed %s section in '%s'...?\n",
+ curr_section_name, objfile->name);
- fde_chunks_need_space ();
- fde = fde_unit_alloc ();
+ cie = cie_chunks;
+ while (cie)
+ {
+ if (cie->objfile == objfile)
+ {
+ if (eh_frame &&
+ (cie->offset ==
+ (unit_offset + bytes_read - cie_id)))
+ break;
+ if (!eh_frame && (cie->offset == cie_id))
+ break;
+ }
+
+ cie = cie->next;
+ }
+ if (!cie)
+ error ("CFI: can't find CIE pointer");
+ }
- fde_chunks.array[fde_chunks.elems++] = fde;
+ init_loc = read_encoded_pointer (abfd, &start,
+ cie->addr_encoding);
- fde->initial_location = read_pointer (abfd, &start)
- + ANOFFSET (objfile->section_offsets,
- SECT_OFF_TEXT (objfile));
- fde->address_range = read_pointer (abfd, &start);
+ switch (pointer_encoding (cie->addr_encoding))
+ {
+ case PE_absptr:
+ break;
+ case PE_pcrel:
+ /* start-frame_buffer gives offset from
+ the beginning of actual section. */
+ init_loc += curr_section_vma + start - frame_buffer;
+ break;
+ default:
+ warning ("CFI: Unsupported pointer encoding\n");
+ }
- cie = cie_chunks;
- while (cie)
+ /* For relocatable objects we must add an offset telling
+ where the section is actually mapped in the memory. */
+ init_loc += ANOFFSET (objfile->section_offsets,
+ SECT_OFF_TEXT (objfile));
+
+ /* If we have both .debug_frame and .eh_frame present in
+ a file, we must eliminate duplicate FDEs. For now we'll
+ run through all entries in fde_chunks and check it one
+ by one. Perhaps in the future we can implement a faster
+ searching algorithm. */
+ /* eh_frame==2 indicates, that this file has an already
+ parsed .debug_frame too. When eh_frame==1 it means, that no
+ .debug_frame is present and thus we don't need to check for
+ duplicities. eh_frame==0 means, that we parse .debug_frame
+ and don't need to care about duplicate FDEs, because
+ .debug_frame is parsed first. */
+ if (eh_frame == 2)
+ for (i = 0; eh_frame == 2 && i < fde_chunks.elems; i++)
{
- if (cie->objfile == objfile)
+ /* We assume that FDEs in .debug_frame and .eh_frame
+ have the same order (if they are present, of course).
+ If we find a duplicate entry for one FDE and save
+ it's index to last_dup_fde it's very likely, that
+ we'll find an entry for the following FDE right after
+ the previous one. Thus in many cases we'll run this
+ loop only once. */
+ last_dup_fde = (last_dup_fde + i) % fde_chunks.elems;
+ if (fde_chunks.array[last_dup_fde]->initial_location
+ == init_loc)
{
- if (from_eh
- && (cie->offset ==
- (unit_offset + bytes_read - cie_id)))
- break;
- if (!from_eh && (cie->offset == cie_id))
- break;
+ dup = 1;
+ break;
}
-
- cie = cie->next;
}
- if (!cie)
- error ("%s(): can't find CIE pointer", __func__);
- fde->cie_ptr = cie;
+ /* Allocate a new entry only if this FDE isn't a duplicate of
+ something we have already seen. */
+ if (!dup)
+ {
+ fde_chunks_need_space ();
+ fde = fde_unit_alloc ();
+
+ fde_chunks.array[fde_chunks.elems++] = fde;
+
+ fde->initial_location = init_loc;
+ fde->address_range = read_encoded_pointer (abfd, &start,
+ cie->
+ addr_encoding);
- if (cie->augmentation[0] == 'z')
- read_uleb128 (abfd, &start);
+ fde->cie_ptr = cie;
- fde->data = start;
- fde->data_length = block_end - start;
+ /* Here we intentionally ignore augmentation data
+ from FDE, because we don't need them. */
+ if (cie->augmentation[0] == 'z')
+ start += read_uleb128 (abfd, &start);
+
+ fde->data = start;
+ fde->data_length = block_end - start;
+ }
}
start = block_end;
}
sizeof (struct fde_unit *), compare_fde_unit);
}
}
-\f
+
+/* We must parse both .debug_frame section and .eh_frame because
+ * not all frames must be present in both of these sections. */
+void
+dwarf2_build_frame_info (struct objfile *objfile)
+{
+ int after_debug_frame = 0;
+
+ /* If we have .debug_frame then the parser is called with
+ eh_frame==0 for .debug_frame and eh_frame==2 for .eh_frame,
+ otherwise it's only called once for .eh_frame with argument
+ eh_frame==1. */
+
+ if (dwarf_frame_offset)
+ {
+ parse_frame_info (objfile, dwarf_frame_offset,
+ dwarf_frame_size, 0 /* = debug_frame */);
+ after_debug_frame = 1;
+ }
+
+ if (dwarf_eh_frame_offset)
+ parse_frame_info (objfile, dwarf_eh_frame_offset, dwarf_eh_frame_size,
+ 1 /* = eh_frame */ + after_debug_frame);
+}
/* Return the frame address. */
CORE_ADDR
projects / binutils-gdb.git / commitdiff