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* dwarf2-frame.c: Fix some comments and whitespace problems.
This commit is contained in:
Mark Kettenis
parent
c84fca4d18
commit
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@ -1,5 +1,7 @@
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2003-11-27 Mark Kettenis <kettenis@gnu.org>
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* dwarf2-frame.c: Fix some comments and whitespace problems.
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* i386nbsd-tdep.c: Don't include "gdbtypes.h". Include
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"gdb_assert.h" and "gdb_string.h".
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(i386nbsd_r_reg_offset): Rename from regmap.
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@ -99,19 +99,18 @@ static struct dwarf2_fde *dwarf2_frame_find_fde (CORE_ADDR *pc);
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enum dwarf2_reg_rule
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{
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/* Make certain that 0 maps onto the correct enum value - the
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/* Make certain that 0 maps onto the correct enum value; the
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corresponding structure is being initialized using memset zero.
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This indicates that CFI didn't provide any information at all
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about a register - leaving how to obtain it's value totally
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about a register, leaving how to obtain it's value totally
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unspecified. */
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REG_UNSPECIFIED = 0,
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/* The term "undefined" comes from the DWARF2 CFI spec which this
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code is moddeling - it indicates that the register's value is
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"undefined". */
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/* NOTE: cagney/2003-09-08: GCC uses the less formal term "unsaved"
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- it's definition is a combination of REG_UNDEFINED and
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REG_UNSPECIFIED - the failure to differentiate the two helps
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explain a few problems with the CFI GCC outputs. */
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code is moddeling; it indicates that the register's value is
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"undefined". GCC uses the less formal term "unsaved". Its
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definition is a combination of REG_UNDEFINED and REG_UNSPECIFIED.
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The failure to differentiate the two helps explain a few problems
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with the CFI generated by GCC. */
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REG_UNDEFINED,
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REG_SAVED_OFFSET,
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REG_SAVED_REG,
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@ -500,18 +499,15 @@ dwarf2_frame_cache (struct frame_info *next_frame, void **this_cache)
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to abort), the compiler might optimize away the instruction at
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NEXT_FRAME's return address. As a result the return address will
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point at some random instruction, and the CFI for that
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instruction is probably wortless to us. GCC's unwinder solves
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instruction is probably worthless to us. GCC's unwinder solves
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this problem by substracting 1 from the return address to get an
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address in the middle of a presumed call instruction (or the
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instruction in the associated delay slot). This should only be
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done for "normal" frames and not for resume-type frames (signal
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handlers, sentinel frames, dummy frames).
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frame_unwind_address_in_block does just this.
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It's not clear how reliable the method is though - there is the
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potential for the register state pre-call being different to that
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on return. */
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handlers, sentinel frames, dummy frames). The function
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frame_unwind_address_in_block does just this. It's not clear how
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reliable the method is though; there is the potential for the
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register state pre-call being different to that on return. */
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fs->pc = frame_unwind_address_in_block (next_frame);
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/* Find the correct FDE. */
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@ -555,6 +551,7 @@ dwarf2_frame_cache (struct frame_info *next_frame, void **this_cache)
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unspecified. */
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{
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int regnum;
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for (regnum = 0; regnum < num_regs; regnum++)
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cache->reg[regnum].how = REG_UNSPECIFIED;
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}
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@ -563,6 +560,7 @@ dwarf2_frame_cache (struct frame_info *next_frame, void **this_cache)
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location information in the cache. */
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{
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int column; /* CFI speak for "register number". */
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for (column = 0; column < fs->regs.num_regs; column++)
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{
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int regnum;
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@ -573,9 +571,10 @@ dwarf2_frame_cache (struct frame_info *next_frame, void **this_cache)
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RETADDR_COLUMN corresponds to a real register (and,
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worse, that isn't the PC_REGNUM)? I'm guessing that the
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PC_REGNUM further down is trying to handle this. That
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can't be right though - PC_REGNUM may not be valid (it
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can be -ve). I think, instead when RETADDR_COLUM isn't a
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real register, it should map itself onto frame_pc_unwind. */
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can't be right though; PC_REGNUM may not be valid (it can
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be negative). I think, instead when RETADDR_COLUM isn't
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a real register, it should map itself onto
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frame_pc_unwind. */
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continue;
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/* Use the GDB register number as the destination index. */
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@ -586,15 +585,15 @@ dwarf2_frame_cache (struct frame_info *next_frame, void **this_cache)
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continue;
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/* NOTE: cagney/2003-09-05: CFI should specify the disposition
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of all debug info registers. If it doesn't complain (but
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not too loudly). It turns out that GCC, assumes that an
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of all debug info registers. If it doesn't, complain (but
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not too loudly). It turns out that GCC assumes that an
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unspecified register implies "same value" when CFI (draft
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7) specifies nothing at all. Such a register could equally
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be interpreted as "undefined". Also note that this check
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isn't sufficient - it only checks that all registers in the
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range [0 .. max column] are specified - and won't detect
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isn't sufficient; it only checks that all registers in the
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range [0 .. max column] are specified, and won't detect
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problems when a debug info register falls outside of the
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table. Need a way of iterating through all the valid
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table. We need a way of iterating through all the valid
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DWARF2 register numbers. */
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if (fs->regs.reg[column].how == REG_UNSPECIFIED)
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complaint (&symfile_complaints,
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@ -606,14 +605,14 @@ dwarf2_frame_cache (struct frame_info *next_frame, void **this_cache)
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}
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/* Store the location of the return addess. If the return address
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column (adjusted) is not the same as gdb's PC_REGNUM, then this
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implies a copy from the ra column register. */
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column (adjusted) is not the same as GDB's PC_REGNUM, then this
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implies a copy from the return address column register. */
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if (fs->retaddr_column < fs->regs.num_regs
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&& fs->regs.reg[fs->retaddr_column].how != REG_UNDEFINED)
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{
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/* See comment above about a possibly -ve PC_REGNUM. If this
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assertion fails, it's a problem with this code and not the
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architecture. */
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/* See comment above about a possibly negative PC_REGNUM. If
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this assertion fails, it's a problem with this code and not
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the architecture. */
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gdb_assert (PC_REGNUM >= 0);
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cache->reg[PC_REGNUM] = fs->regs.reg[fs->retaddr_column];
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}
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@ -622,9 +621,9 @@ dwarf2_frame_cache (struct frame_info *next_frame, void **this_cache)
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int reg = DWARF2_REG_TO_REGNUM (fs->retaddr_column);
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if (reg != PC_REGNUM)
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{
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/* See comment above about PC_REGNUM being -ve. If this
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assertion fails, it's a problem with this code and not
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the architecture. */
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/* See comment above about PC_REGNUM being negative. If
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this assertion fails, it's a problem with this code and
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not the architecture. */
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gdb_assert (PC_REGNUM >= 0);
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cache->reg[PC_REGNUM].loc.reg = reg;
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cache->reg[PC_REGNUM].how = REG_SAVED_REG;
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@ -660,7 +659,7 @@ dwarf2_frame_prev_register (struct frame_info *next_frame, void **this_cache,
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{
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case REG_UNDEFINED:
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/* If CFI explicitly specified that the value isn't defined,
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mark it as optimized away - the value isn't available. */
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mark it as optimized away; the value isn't available. */
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*optimizedp = 1;
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*lvalp = not_lval;
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*addrp = 0;
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@ -681,8 +680,8 @@ dwarf2_frame_prev_register (struct frame_info *next_frame, void **this_cache,
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/* FIXME: cagney/2003-07-07: I don't understand this. The
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CFI info should have provided unwind information for the
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SP register and then pointed ->cfa_reg at it, not the
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reverse. Assuming that SP_REGNUM is !-ve, there is a
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very real posibility that CFA is an offset from some
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reverse. Assuming that SP_REGNUM isn't negative, there
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is a very real posibility that CFA is an offset from some
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other register, having nothing to do with the unwound SP
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value. */
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/* FIXME: cagney/2003-09-05: I think I understand. GDB was
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@ -770,7 +769,7 @@ dwarf2_frame_prev_register (struct frame_info *next_frame, void **this_cache,
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defines the rule which computes the CFA value; it may be
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either a register and a signed offset that are added
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together or a DWARF expression that is evaluated. */
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/* NOTE: cagney/2003-09-05: Should issue a complain.
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/* NOTE: cagney/2003-09-05: Should issue a complaint.
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Unfortunately it turns out that DWARF2 CFI has a problem.
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Since CFI specifies the location at which a register was
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saved (not its value) it isn't possible to specify
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