/* Interface to prologue value handling for GDB.
- Copyright 2003, 2004, 2005, 2007, 2008, 2009, 2010, 2011
- Free Software Foundation, Inc.
+ Copyright (C) 2003-2020 Free Software Foundation, Inc.
This file is part of GDB.
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
- along with this program. If not, see <http://www.gnu.org/licenses/>. */
+ along with this program. If not, see <http://www.gnu.org/licenses/>. */
#ifndef PROLOGUE_VALUE_H
#define PROLOGUE_VALUE_H
+/* What sort of value is this? This determines the interpretation
+ of subsequent fields. */
+enum prologue_value_kind
+{
+ /* We don't know anything about the value. This is also used for
+ values we could have kept track of, when doing so would have
+ been too complex and we don't want to bother. The bottom of
+ our lattice. */
+ pvk_unknown,
+
+ /* A known constant. K is its value. */
+ pvk_constant,
+
+ /* The value that register REG originally had *UPON ENTRY TO THE
+ FUNCTION*, plus K. If K is zero, this means, obviously, just
+ the value REG had upon entry to the function. REG is a GDB
+ register number. Before we start interpreting, we initialize
+ every register R to { pvk_register, R, 0 }. */
+ pvk_register,
+};
+
/* When we analyze a prologue, we're really doing 'abstract
interpretation' or 'pseudo-evaluation': running the function's code
in simulation, but using conservative approximations of the values
understand and maintain. In the approach used here:
- It's easier to see that the analyzer is correct: you just see
- whether the analyzer properly (albiet conservatively) simulates
+ whether the analyzer properly (albeit conservatively) simulates
the effect of each instruction.
- It's easier to extend the analyzer: you can add support for new
/* What sort of value is this? This determines the interpretation
of subsequent fields. */
- enum {
-
- /* We don't know anything about the value. This is also used for
- values we could have kept track of, when doing so would have
- been too complex and we don't want to bother. The bottom of
- our lattice. */
- pvk_unknown,
-
- /* A known constant. K is its value. */
- pvk_constant,
-
- /* The value that register REG originally had *UPON ENTRY TO THE
- FUNCTION*, plus K. If K is zero, this means, obviously, just
- the value REG had upon entry to the function. REG is a GDB
- register number. Before we start interpreting, we initialize
- every register R to { pvk_register, R, 0 }. */
- pvk_register,
-
- } kind;
+ enum prologue_value_kind kind;
/* The meanings of the following fields depend on 'kind'; see the
comments for the specific 'kind' values. */
int *i);
-/* A 'struct pv_area' keeps track of values stored in a particular
- region of memory. */
-struct pv_area;
+/* A 'pv_area' keeps track of values stored in a particular region of
+ memory. */
+class pv_area
+{
+public:
-/* Create a new area, tracking stores relative to the original value
- of BASE_REG. If BASE_REG is SP, then this effectively records the
- contents of the stack frame: the original value of the SP is the
- frame's CFA, or some constant offset from it.
+ /* Create a new area, tracking stores relative to the original value
+ of BASE_REG. If BASE_REG is SP, then this effectively records the
+ contents of the stack frame: the original value of the SP is the
+ frame's CFA, or some constant offset from it.
- Stores to constant addresses, unknown addresses, or to addresses
- relative to registers other than BASE_REG will trash this area; see
- pv_area_store_would_trash.
+ Stores to constant addresses, unknown addresses, or to addresses
+ relative to registers other than BASE_REG will trash this area; see
+ pv_area::store_would_trash.
- To check whether a pointer refers to this area, only the low
- ADDR_BIT bits will be compared. */
-struct pv_area *make_pv_area (int base_reg, int addr_bit);
+ To check whether a pointer refers to this area, only the low
+ ADDR_BIT bits will be compared. */
+ pv_area (int base_reg, int addr_bit);
-/* Free AREA. */
-void free_pv_area (struct pv_area *area);
+ ~pv_area ();
+ DISABLE_COPY_AND_ASSIGN (pv_area);
-/* Register a cleanup to free AREA. */
-struct cleanup *make_cleanup_free_pv_area (struct pv_area *area);
+ /* Store the SIZE-byte value VALUE at ADDR in AREA.
+ If ADDR is not relative to the same base register we used in
+ creating AREA, then we can't tell which values here the stored
+ value might overlap, and we'll have to mark everything as
+ unknown. */
+ void store (pv_t addr,
+ CORE_ADDR size,
+ pv_t value);
-/* Store the SIZE-byte value VALUE at ADDR in AREA.
+ /* Return the SIZE-byte value at ADDR in AREA. This may return
+ pv_unknown (). */
+ pv_t fetch (pv_t addr, CORE_ADDR size);
- If ADDR is not relative to the same base register we used in
- creating AREA, then we can't tell which values here the stored
- value might overlap, and we'll have to mark everything as
- unknown. */
-void pv_area_store (struct pv_area *area,
- pv_t addr,
- CORE_ADDR size,
- pv_t value);
+ /* Return true if storing to address ADDR in AREA would force us to
+ mark the contents of the entire area as unknown. This could happen
+ if, say, ADDR is unknown, since we could be storing anywhere. Or,
+ it could happen if ADDR is relative to a different register than
+ the other stores base register, since we don't know the relative
+ values of the two registers.
-/* Return the SIZE-byte value at ADDR in AREA. This may return
- pv_unknown (). */
-pv_t pv_area_fetch (struct pv_area *area, pv_t addr, CORE_ADDR size);
+ If you've reached such a store, it may be better to simply stop the
+ prologue analysis, and return the information you've gathered,
+ instead of losing all that information, most of which is probably
+ okay. */
+ bool store_would_trash (pv_t addr);
-/* Return true if storing to address ADDR in AREA would force us to
- mark the contents of the entire area as unknown. This could happen
- if, say, ADDR is unknown, since we could be storing anywhere. Or,
- it could happen if ADDR is relative to a different register than
- the other stores base register, since we don't know the relative
- values of the two registers.
+ /* Search AREA for the original value of REGISTER. If we can't find
+ it, return zero; if we can find it, return a non-zero value, and if
+ OFFSET_P is non-zero, set *OFFSET_P to the register's offset within
+ AREA. GDBARCH is the architecture of which REGISTER is a member.
- If you've reached such a store, it may be better to simply stop the
- prologue analysis, and return the information you've gathered,
- instead of losing all that information, most of which is probably
- okay. */
-int pv_area_store_would_trash (struct pv_area *area, pv_t addr);
+ In the worst case, this takes time proportional to the number of
+ items stored in AREA. If you plan to gather a lot of information
+ about registers saved in AREA, consider calling pv_area::scan
+ instead, and collecting all your information in one pass. */
+ bool find_reg (struct gdbarch *gdbarch, int reg, CORE_ADDR *offset_p);
-/* Search AREA for the original value of REGISTER. If we can't find
- it, return zero; if we can find it, return a non-zero value, and if
- OFFSET_P is non-zero, set *OFFSET_P to the register's offset within
- AREA. GDBARCH is the architecture of which REGISTER is a member.
+ /* For every part of AREA whose value we know, apply FUNC to CLOSURE,
+ the value's address, its size, and the value itself. */
+ void scan (void (*func) (void *closure,
+ pv_t addr,
+ CORE_ADDR size,
+ pv_t value),
+ void *closure);
- In the worst case, this takes time proportional to the number of
- items stored in AREA. If you plan to gather a lot of information
- about registers saved in AREA, consider calling pv_area_scan
- instead, and collecting all your information in one pass. */
-int pv_area_find_reg (struct pv_area *area,
- struct gdbarch *gdbarch,
- int reg,
- CORE_ADDR *offset_p);
+private:
+ struct area_entry;
-/* For every part of AREA whose value we know, apply FUNC to CLOSURE,
- the value's address, its size, and the value itself. */
-void pv_area_scan (struct pv_area *area,
- void (*func) (void *closure,
- pv_t addr,
- CORE_ADDR size,
- pv_t value),
- void *closure);
+ /* Delete all entries from AREA. */
+ void clear_entries ();
+ /* Return a pointer to the first entry we hit in AREA starting at
+ OFFSET and going forward.
+
+ This may return zero, if AREA has no entries.
+
+ And since the entries are a ring, this may return an entry that
+ entirely precedes OFFSET. This is the correct behavior: depending
+ on the sizes involved, we could still overlap such an area, with
+ wrap-around. */
+ struct area_entry *find_entry (CORE_ADDR offset);
+
+ /* Return non-zero if the SIZE bytes at OFFSET would overlap ENTRY;
+ return zero otherwise. AREA is the area to which ENTRY belongs. */
+ int overlaps (struct area_entry *entry,
+ CORE_ADDR offset,
+ CORE_ADDR size);
+
+ /* This area's base register. */
+ int m_base_reg;
+
+ /* The mask to apply to addresses, to make the wrap-around happen at
+ the right place. */
+ CORE_ADDR m_addr_mask;
+
+ /* An element of the doubly-linked ring of entries, or zero if we
+ have none. */
+ struct area_entry *m_entry;
+};
#endif /* PROLOGUE_VALUE_H */
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