[PATCH] Cleanup i386-nat.c

Mark Kettenis
2004-02-28T15:38:28Z

The coding style in this file had some quirks, so I committed the
attached.

Mark

Index: ChangeLog
from Mark Kettenis <kettenis@gnu.org>

* i386-nat.c: Reformat to be closer to coding standards.
(i386_handle_nonaligned_watchpoint): Rename local variable `rv' to
`retval'. Make variables `align' and `size' local to while-loop.
(i386_stopped_data_address): Rename local variable `ret' to `addr'.
(_initialize_i386_nat): New prototype.

Index: i386-nat.c
===================================================================
RCS file: /cvs/src/src/gdb/i386-nat.c,v
retrieving revision 1.6
diff -u -p -r1.6 i386-nat.c
--- i386-nat.c 17 Aug 2003 18:22:25 -0000 1.6
+++ i386-nat.c 28 Feb 2004 15:14:22 -0000
@@ -1,5 +1,6 @@
-/* Intel x86 (a.k.a. ia32) native-dependent code.
- Copyright (C) 2001 Free Software Foundation, Inc.
+/* Native-dependent code for the i386.
+
+ Copyright 2001, 2004 Free Software Foundation, Inc.

This file is part of GDB.

@@ -23,24 +24,24 @@
#include "command.h"
#include "gdbcmd.h"

-/* Support for hardware watchpoints and breakpoints using the x86
+/* Support for hardware watchpoints and breakpoints using the i386
debug registers.

This provides several functions for inserting and removing
- hardware-assisted breakpoints and watchpoints, testing if
- one or more of the watchpoints triggered and at what address,
- checking whether a given region can be watched, etc.
-
- A target which wants to use these functions should define
- several macros, such as `target_insert_watchpoint' and
- `target_stopped_data_address', listed in target.h, to call
- the appropriate functions below. It should also define
+ hardware-assisted breakpoints and watchpoints, testing if one or
+ more of the watchpoints triggered and at what address, checking
+ whether a given region can be watched, etc.
+
+ A target which wants to use these functions should define several
+ macros, such as `target_insert_watchpoint' and
+ `target_stopped_data_address', listed in target.h, to call the
+ appropriate functions below. It should also define
I386_USE_GENERIC_WATCHPOINTS in its tm.h file.

- In addition, each target should provide several low-level
- macros that will be called to insert watchpoints and hardware
- breakpoints into the inferior, remove them, and check their
- status. These macros are:
+ In addition, each target should provide several low-level macros
+ that will be called to insert watchpoints and hardware breakpoints
+ into the inferior, remove them, and check their status. These
+ macros are:

I386_DR_LOW_SET_CONTROL -- set the debug control (DR7)
register to a given value
@@ -54,21 +55,20 @@
I386_DR_LOW_GET_STATUS -- return the value of the debug
status (DR6) register.

- The functions below implement debug registers sharing by
- reference counts, and allow to watch regions up to 16 bytes
- long. */
+ The functions below implement debug registers sharing by reference
+ counts, and allow to watch regions up to 16 bytes long. */

#ifdef I386_USE_GENERIC_WATCHPOINTS

/* Support for 8-byte wide hw watchpoints. */
#ifndef TARGET_HAS_DR_LEN_8
-#define TARGET_HAS_DR_LEN_8 0
+#define TARGET_HAS_DR_LEN_8 0
#endif

/* Debug registers' indices. */
-#define DR_NADDR 4 /* the number of debug address registers */
-#define DR_STATUS 6 /* index of debug status register (DR6) */
-#define DR_CONTROL 7 /* index of debug control register (DR7) */
+#define DR_NADDR 4 /* The number of debug address registers. */
+#define DR_STATUS 6 /* Index of debug status register (DR6). */
+#define DR_CONTROL 7 /* Index of debug control register (DR7). */

/* DR7 Debug Control register fields. */

@@ -78,46 +78,46 @@
#define DR_CONTROL_SIZE 4

/* Watchpoint/breakpoint read/write fields in DR7. */
-#define DR_RW_EXECUTE (0x0) /* break on instruction execution */
-#define DR_RW_WRITE (0x1) /* break on data writes */
-#define DR_RW_READ (0x3) /* break on data reads or writes */
+#define DR_RW_EXECUTE (0x0) /* Break on instruction execution. */
+#define DR_RW_WRITE (0x1) /* Break on data writes. */
+#define DR_RW_READ (0x3) /* Break on data reads or writes. */

/* This is here for completeness. No platform supports this
- functionality yet (as of Mar-2001). Note that the DE flag in the
+ functionality yet (as of March 2001). Note that the DE flag in the
CR4 register needs to be set to support this. */
#ifndef DR_RW_IORW
-#define DR_RW_IORW (0x2) /* break on I/O reads or writes */
+#define DR_RW_IORW (0x2) /* Break on I/O reads or writes. */
#endif

/* Watchpoint/breakpoint length fields in DR7. The 2-bit left shift
is so we could OR this with the read/write field defined above. */
-#define DR_LEN_1 (0x0 << 2) /* 1-byte region watch or breakpt */
-#define DR_LEN_2 (0x1 << 2) /* 2-byte region watch */
-#define DR_LEN_4 (0x3 << 2) /* 4-byte region watch */
-#define DR_LEN_8 (0x2 << 2) /* 8-byte region watch (x86-64) */
+#define DR_LEN_1 (0x0 << 2) /* 1-byte region watch or breakpoint. */
+#define DR_LEN_2 (0x1 << 2) /* 2-byte region watch. */
+#define DR_LEN_4 (0x3 << 2) /* 4-byte region watch. */
+#define DR_LEN_8 (0x2 << 2) /* 8-byte region watch (AMD64). */

/* Local and Global Enable flags in DR7.

When the Local Enable flag is set, the breakpoint/watchpoint is
enabled only for the current task; the processor automatically
- clears this flag on every task switch. When the Global Enable
- flag is set, the breakpoint/watchpoint is enabled for all tasks;
- the processor never clears this flag.
+ clears this flag on every task switch. When the Global Enable flag
+ is set, the breakpoint/watchpoint is enabled for all tasks; the
+ processor never clears this flag.

Currently, all watchpoint are locally enabled. If you need to
enable them globally, read the comment which pertains to this in
i386_insert_aligned_watchpoint below. */
-#define DR_LOCAL_ENABLE_SHIFT 0 /* extra shift to the local enable bit */
-#define DR_GLOBAL_ENABLE_SHIFT 1 /* extra shift to the global enable bit */
-#define DR_ENABLE_SIZE 2 /* 2 enable bits per debug register */
+#define DR_LOCAL_ENABLE_SHIFT 0 /* Extra shift to the local enable bit. */
+#define DR_GLOBAL_ENABLE_SHIFT 1 /* Extra shift to the global enable bit. */
+#define DR_ENABLE_SIZE 2 /* Two enable bits per debug register. */

/* Local and global exact breakpoint enable flags (a.k.a. slowdown
flags). These are only required on i386, to allow detection of the
exact instruction which caused a watchpoint to break; i486 and
later processors do that automatically. We set these flags for
- back compatibility. */
+ backwards compatibility. */
#define DR_LOCAL_SLOWDOWN (0x100)
-#define DR_GLOBAL_SLOWDOWN (0x200)
+#define DR_GLOBAL_SLOWDOWN (0x200)

/* Fields reserved by Intel. This includes the GD (General Detect
Enable) flag, which causes a debug exception to be generated when a
@@ -129,7 +129,7 @@
/* Auxiliary helper macros. */

/* A value that masks all fields in DR7 that are reserved by Intel. */
-#define I386_DR_CONTROL_MASK (~DR_CONTROL_RESERVED)
+#define I386_DR_CONTROL_MASK (~DR_CONTROL_RESERVED)

/* The I'th debug register is vacant if its Local and Global Enable
bits are reset in the Debug Control register. */
@@ -168,13 +168,13 @@
/* Mirror the inferior's DRi registers. We keep the status and
control registers separated because they don't hold addresses. */
static CORE_ADDR dr_mirror[DR_NADDR];
-static unsigned dr_status_mirror, dr_control_mirror;
+static unsigned dr_status_mirror, dr_control_mirror;

/* Reference counts for each debug register. */
-static int dr_ref_count[DR_NADDR];
+static int dr_ref_count[DR_NADDR];

/* Whether or not to print the mirrored debug registers. */
-static int maint_show_dr;
+static int maint_show_dr;

/* Types of operations supported by i386_handle_nonaligned_watchpoint. */
typedef enum { WP_INSERT, WP_REMOVE, WP_COUNT } i386_wp_op_t;
@@ -182,8 +182,8 @@ typedef enum { WP_INSERT, WP_REMOVE, WP_
/* Internal functions. */

/* Return the value of a 4-bit field for DR7 suitable for watching a
- region of LEN bytes for accesses of type TYPE. LEN is assumed
- to have the value of 1, 2, or 4. */
+ region of LEN bytes for accesses of type TYPE. LEN is assumed to
+ have the value of 1, 2, or 4. */
static unsigned i386_length_and_rw_bits (int len, enum target_hw_bp_type type);

/* Insert a watchpoint at address ADDR, which is assumed to be aligned
@@ -206,16 +206,17 @@ static int i386_remove_aligned_watchpoin
number of debug registers required to watch a region at address
ADDR whose length is LEN for accesses of type TYPE. Return 0 on
successful insertion or removal, a positive number when queried
- about the number of registers, or -1 on failure. If WHAT is not
- a valid value, bombs through internal_error. */
+ about the number of registers, or -1 on failure. If WHAT is not a
+ valid value, bombs through internal_error. */
static int i386_handle_nonaligned_watchpoint (i386_wp_op_t what,
CORE_ADDR addr, int len,
enum target_hw_bp_type type);

/* Implementation. */

-/* Clear the reference counts and forget everything we knew about
- the debug registers. */
+/* Clear the reference counts and forget everything we knew about the
+ debug registers. */
+
void
i386_cleanup_dregs (void)
{
@@ -231,18 +232,22 @@ i386_cleanup_dregs (void)
}

#ifndef LINUX_CHILD_POST_STARTUP_INFERIOR
-/* Reset all debug registers at each new startup
- to avoid missing watchpoints after restart. */
+
+/* Reset all debug registers at each new startup to avoid missing
+ watchpoints after restart. */
+
void
child_post_startup_inferior (ptid_t ptid)
{
i386_cleanup_dregs ();
}
+
#endif /* LINUX_CHILD_POST_STARTUP_INFERIOR */

-/* Print the values of the mirrored debug registers.
- This is called when maint_show_dr is non-zero. To set that
- up, type "maint show-debug-regs" at GDB's prompt. */
+/* Print the values of the mirrored debug registers. This is called
+ when maint_show_dr is non-zero. To set that up, type "maint
+ show-debug-regs" at GDB's prompt. */
+
static void
i386_show_dr (const char *func, CORE_ADDR addr,
int len, enum target_hw_bp_type type)
@@ -268,7 +273,8 @@ i386_show_dr (const char *func, CORE_ADD
dr_control_mirror, dr_status_mirror);
ALL_DEBUG_REGISTERS(i)
{
- printf_unfiltered ("\tDR%d: addr=0x%s, ref.count=%d DR%d: addr=0x%s, ref.count=%d\n",
+ printf_unfiltered ("\
+\tDR%d: addr=0x%s, ref.count=%d DR%d: addr=0x%s, ref.count=%d\n",
i, paddr(dr_mirror[i]), dr_ref_count[i],
i+1, paddr(dr_mirror[i+1]), dr_ref_count[i+1]);
i++;
@@ -276,8 +282,9 @@ i386_show_dr (const char *func, CORE_ADD
}

/* Return the value of a 4-bit field for DR7 suitable for watching a
- region of LEN bytes for accesses of type TYPE. LEN is assumed
- to have the value of 1, 2, or 4. */
+ region of LEN bytes for accesses of type TYPE. LEN is assumed to
+ have the value of 1, 2, or 4. */
+
static unsigned
i386_length_and_rw_bits (int len, enum target_hw_bp_type type)
{
@@ -291,18 +298,21 @@ i386_length_and_rw_bits (int len, enum t
case hw_write:
rw = DR_RW_WRITE;
break;
- case hw_read: /* x86 doesn't support data-read watchpoints */
+ case hw_read:
+ /* The i386 doesn't support data-read watchpoints. */
case hw_access:
rw = DR_RW_READ;
break;
#if 0
- case hw_io_access: /* not yet supported */
+ /* Not yet supported. */
+ case hw_io_access:
rw = DR_RW_IORW;
break;
#endif
default:
internal_error (__FILE__, __LINE__, "\
-Invalid hw breakpoint type %d in i386_length_and_rw_bits.\n", (int)type);
+Invalid hardware breakpoint type %d in i386_length_and_rw_bits.\n",
+ (int) type);
}

switch (len)
@@ -318,7 +328,7 @@ Invalid hw breakpoint type %d in i386_le
return (DR_LEN_8 | rw);
default:
internal_error (__FILE__, __LINE__, "\
-Invalid hw breakpoint length %d in i386_length_and_rw_bits.\n", len);
+Invalid hardware breakpoint length %d in i386_length_and_rw_bits.\n", len);
}
}

@@ -327,6 +337,7 @@ Invalid hw breakpoint length %d in i386_
value of the bits from DR7 which describes the length and access
type of the region to be watched by this watchpoint. Return 0 on
success, -1 on failure. */
+
static int
i386_insert_aligned_watchpoint (CORE_ADDR addr, unsigned len_rw_bits)
{
@@ -364,7 +375,7 @@ i386_insert_aligned_watchpoint (CORE_ADD
dr_ref_count[i] = 1;
I386_DR_SET_RW_LEN (i, len_rw_bits);
/* Note: we only enable the watchpoint locally, i.e. in the current
- task. Currently, no x86 target allows or supports global
+ task. Currently, no i386 target allows or supports global
watchpoints; however, if any target would want that in the
future, GDB should probably provide a command to control whether
to enable watchpoints globally or locally, and the code below
@@ -386,6 +397,7 @@ i386_insert_aligned_watchpoint (CORE_ADD
value of the bits from DR7 which describes the length and access
type of the region watched by this watchpoint. Return 0 on
success, -1 on failure. */
+
static int
i386_remove_aligned_watchpoint (CORE_ADDR addr, unsigned len_rw_bits)
{
@@ -417,42 +429,46 @@ i386_remove_aligned_watchpoint (CORE_ADD
number of debug registers required to watch a region at address
ADDR whose length is LEN for accesses of type TYPE. Return 0 on
successful insertion or removal, a positive number when queried
- about the number of registers, or -1 on failure. If WHAT is not
- a valid value, bombs through internal_error. */
+ about the number of registers, or -1 on failure. If WHAT is not a
+ valid value, bombs through internal_error. */
+
static int
i386_handle_nonaligned_watchpoint (i386_wp_op_t what, CORE_ADDR addr, int len,
enum target_hw_bp_type type)
{
- int align;
- int size;
- int rv = 0, status = 0;
+ int retval = 0, status = 0;
int max_wp_len = TARGET_HAS_DR_LEN_8 ? 8 : 4;

static int size_try_array[8][8] =
{
- {1, 1, 1, 1, 1, 1, 1, 1}, /* trying size one */
- {2, 1, 2, 1, 2, 1, 2, 1}, /* trying size two */
- {2, 1, 2, 1, 2, 1, 2, 1}, /* trying size three */
- {4, 1, 2, 1, 4, 1, 2, 1}, /* trying size four */
- {4, 1, 2, 1, 4, 1, 2, 1}, /* trying size five */
- {4, 1, 2, 1, 4, 1, 2, 1}, /* trying size six */
- {4, 1, 2, 1, 4, 1, 2, 1}, /* trying size seven */
- {8, 1, 2, 1, 4, 1, 2, 1}, /* trying size eight */
+ {1, 1, 1, 1, 1, 1, 1, 1}, /* Trying size one. */
+ {2, 1, 2, 1, 2, 1, 2, 1}, /* Trying size two. */
+ {2, 1, 2, 1, 2, 1, 2, 1}, /* Trying size three. */
+ {4, 1, 2, 1, 4, 1, 2, 1}, /* Trying size four. */
+ {4, 1, 2, 1, 4, 1, 2, 1}, /* Trying size five. */
+ {4, 1, 2, 1, 4, 1, 2, 1}, /* Trying size six. */
+ {4, 1, 2, 1, 4, 1, 2, 1}, /* Trying size seven. */
+ {8, 1, 2, 1, 4, 1, 2, 1}, /* Trying size eight. */
};

while (len > 0)
{
- align = addr % max_wp_len;
- /* Four(eigth on x86_64) is the maximum length an x86 debug register
+ int align = addr % max_wp_len;
+ /* Four (eigth on AMD64) is the maximum length a debug register
can watch. */
- size = size_try_array[len > max_wp_len ? (max_wp_len - 1) : len - 1][align];
+ int try = (len > max_wp_len ? (max_wp_len - 1) : len - 1);
+ int size = size_try_array[try][align];
+
if (what == WP_COUNT)
- /* size_try_array[] is defined so that each iteration through
- the loop is guaranteed to produce an address and a size
- that can be watched with a single debug register. Thus,
- for counting the registers required to watch a region, we
- simply need to increment the count on each iteration. */
- rv++;
+ {
+ /* size_try_array[] is defined such that each iteration
+ through the loop is guaranteed to produce an address and a
+ size that can be watched with a single debug register.
+ Thus, for counting the registers required to watch a
+ region, we simply need to increment the count on each
+ iteration. */
+ retval++;
+ }
else
{
unsigned len_rw = i386_length_and_rw_bits (size, type);
@@ -475,17 +491,20 @@ Invalid value %d of operation in i386_ha
to our failure to insert this watchpoint and tries to
remove it. */
if (status)
- rv = status;
+ retval = status;
}
+
addr += size;
len -= size;
}
- return rv;
+
+ return retval;
}

/* Insert a watchpoint to watch a memory region which starts at
address ADDR and whose length is LEN bytes. Watch memory accesses
of the type TYPE. Return 0 on success, -1 on failure. */
+
int
i386_insert_watchpoint (CORE_ADDR addr, int len, int type)
{
@@ -533,25 +552,26 @@ i386_remove_watchpoint (CORE_ADDR addr,

/* Return non-zero if we can watch a memory region that starts at
address ADDR and whose length is LEN bytes. */
+
int
i386_region_ok_for_watchpoint (CORE_ADDR addr, int len)
{
+ int nregs;
+
/* Compute how many aligned watchpoints we would need to cover this
region. */
- int nregs = i386_handle_nonaligned_watchpoint (WP_COUNT, addr, len,
- hw_write);
-
+ nregs = i386_handle_nonaligned_watchpoint (WP_COUNT, addr, len, hw_write);
return nregs <= DR_NADDR ? 1 : 0;
}

/* If the inferior has some watchpoint that triggered, return the
- address associated with that watchpoint. Otherwise, return
- zero. */
+ address associated with that watchpoint. Otherwise, return zero. */
+
CORE_ADDR
i386_stopped_data_address (void)
{
+ CORE_ADDR addr = 0;
int i;
- CORE_ADDR ret = 0;

dr_status_mirror = I386_DR_LOW_GET_STATUS ();

@@ -562,22 +582,23 @@ i386_stopped_data_address (void)
watchpoint, not a hardware breakpoint. The reason is
that GDB doesn't call the target_stopped_data_address
method except for data watchpoints. In other words, I'm
- being paranoiac. */
+ being paranoid. */
&& I386_DR_GET_RW_LEN (i) != 0)
{
- ret = dr_mirror[i];
+ addr = dr_mirror[i];
if (maint_show_dr)
- i386_show_dr ("watchpoint_hit", ret, -1, hw_write);
+ i386_show_dr ("watchpoint_hit", addr, -1, hw_write);
}
}
- if (maint_show_dr && ret == 0)
+ if (maint_show_dr && addr == 0)
i386_show_dr ("stopped_data_addr", 0, 0, hw_write);

- return ret;
+ return addr;
}

/* Return non-zero if the inferior has some break/watchpoint that
triggered. */
+
int
i386_stopped_by_hwbp (void)
{
@@ -612,6 +633,7 @@ i386_insert_hw_breakpoint (CORE_ADDR add

/* Remove a hardware-assisted breakpoint at address ADDR. SHADOW is
unused. Return 0 on success, -1 on failure. */
+
int
i386_remove_hw_breakpoint (CORE_ADDR addr, void *shadow)
{
@@ -625,8 +647,11 @@ i386_remove_hw_breakpoint (CORE_ADDR add
}

#endif /* I386_USE_GENERIC_WATCHPOINTS */
-
\f
+
+/* Provide a prototype to silence -Wmissing-prototypes. */
+void _initialize_i386_nat (void);
+
void
_initialize_i386_nat (void)
{