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riscv-gcc-1
Commit 5c7a310f by Mark Mitchell Committed by Mark Mitchell
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emit-rtl.c (start_sequence): Expand comments. 

	* emit-rtl.c (start_sequence): Expand comments.
	(start_sequence_for_rtl_expr): Likewise.
	(push_to_sequence): Likewise.
	(end_sequence): Likewise.
	* expr.c (inhibit_defer_pop): Likewise.
	* expr.h (inhibit_defer_pop): Likewise.
	(NO_DEFER_POP): Likewise.
	(OK_DEFER_POP): Likewise.

From-SVN: r26704
parent 1a6580ec
Showing with 72 additions and 18 deletions
gcc/ChangeLog
Thu Apr 29 23:02:22 1999 Mark Mitchell <mark@codesourcery.com>
* emit-rtl.c (start_sequence): Expand comments.
(start_sequence_for_rtl_expr): Likewise.
(push_to_sequence): Likewise.
(end_sequence): Likewise.
* expr.c (inhibit_defer_pop): Likewise.
* expr.h (inhibit_defer_pop): Likewise.
(NO_DEFER_POP): Likewise.
(OK_DEFER_POP): Likewise.
Thu Apr 29 22:13:46 1999 Robert Lipe <robertlipe@usa.net>
* configure.in (i?86-UnixWare7*-sysv): Set thread_file to 'posix'
......
gcc/emit-rtl.c
......@@ -3284,7 +3284,13 @@ emit (x)
abort ();
}
/* Begin emitting insns to a sequence which can be packaged in an RTL_EXPR. */
/* Begin emitting insns to a sequence which can be packaged in an
RTL_EXPR. If this sequence will contain something that might cause
the compiler to pop arguments to function calls (because those
pops have previously been deferred; see INHIBIT_DEFER_POP for more
details), use do_pending_stack_adjust before calling this function.
That will ensure that the deferred pops are not accidentally
emitted in the middel of this sequence. */
void
start_sequence ()
......@@ -3311,8 +3317,9 @@ start_sequence ()
last_insn = 0;
}
/* Similarly, but indicate that this sequence will be placed in
T, an RTL_EXPR. */
/* Similarly, but indicate that this sequence will be placed in T, an
RTL_EXPR. See the documentation for start_sequence for more
information about how to use this function. */
void
start_sequence_for_rtl_expr (t)
......@@ -3323,8 +3330,9 @@ start_sequence_for_rtl_expr (t)
sequence_rtl_expr = t;
}
/* Set up the insn chain starting with FIRST
as the current sequence, saving the previously current one. */
/* Set up the insn chain starting with FIRST as the current sequence,
saving the previously current one. See the documentation for
start_sequence for more information about how to use this function. */
void
push_to_sequence (first)
......@@ -3378,8 +3386,16 @@ pop_topmost_sequence ()
/* After emitting to a sequence, restore previous saved state.
To get the contents of the sequence just made,
you must call `gen_sequence' *before* calling here. */
To get the contents of the sequence just made, you must call
`gen_sequence' *before* calling here.
If the compiler might have deferred popping arguments while
generating this sequence, and this sequence will not be immediately
inserted into the instruction stream, use do_pending_stack_adjust
before calling gen_sequence. That will ensure that the deferred
pops are inserted into this sequence, and not into some random
location in the instruction stream. See INHIBIT_DEFER_POP for more
information about deferred popping of arguments. */
void
end_sequence ()
......
gcc/expr.c
......@@ -87,10 +87,21 @@ int do_preexpand_calls = 1;
These are the arguments to function calls that have already returned. */
int pending_stack_adjust;
/* Nonzero means stack pops must not be deferred, and deferred stack
pops must not be output. It is nonzero inside a function call,
inside a conditional expression, inside a statement expression,
and in other cases as well. */
/* Under some ABIs, it is the caller's responsibility to pop arguments
pushed for function calls. A naive implementation would simply pop
the arguments immediately after each call. However, if several
function calls are made in a row, it is typically cheaper to pop
all the arguments after all of the calls are complete since a
single pop instruction can be used. Therefore, GCC attempts to
defer popping the arguments until absolutely necessary. (For
example, at the end of a conditional, the arguments must be popped,
since code outside the conditional won't know whether or not the
arguments need to be popped.)
When INHIBIT_DEFER_POP is non-zero, however, the compiler does not
attempt to defer pops. Instead, the stack is popped immediately
after each call. Rather then setting this variable directly, use
NO_DEFER_POP and OK_DEFER_POP. */
int inhibit_defer_pop;
/* Nonzero means __builtin_saveregs has already been done in this function.
......
gcc/expr.h
......@@ -95,12 +95,31 @@ extern rtx current_function_internal_arg_pointer;
function. */
extern int current_function_check_memory_usage;
/* Nonzero means stack pops must not be deferred, and deferred stack
pops must not be output. It is nonzero inside a function call,
inside a conditional expression, inside a statement expression,
and in other cases as well. */
/* Under some ABIs, it is the caller's responsibility to pop arguments
pushed for function calls. A naive implementation would simply pop
the arguments immediately after each call. However, if several
function calls are made in a row, it is typically cheaper to pop
all the arguments after all of the calls are complete since a
single pop instruction can be used. Therefore, GCC attempts to
defer popping the arguments until absolutely necessary. (For
example, at the end of a conditional, the arguments must be popped,
since code outside the conditional won't know whether or not the
arguments need to be popped.)
When INHIBIT_DEFER_POP is non-zero, however, the compiler does not
attempt to defer pops. Instead, the stack is popped immediately
after each call. Rather then setting this variable directly, use
NO_DEFER_POP and OK_DEFER_POP. */
extern int inhibit_defer_pop;
/* Prevent the compiler from deferring stack pops. See
inhibit_defer_pop for more information. */
#define NO_DEFER_POP (inhibit_defer_pop += 1)
/* Allow the compiler to defer stack pops. See inhibit_defer_pop for
more information. */
#define OK_DEFER_POP (inhibit_defer_pop -= 1)
/* Number of function calls seen so far in current function. */
extern int function_call_count;
......@@ -126,9 +145,6 @@ extern rtx nonlocal_goto_stack_level;
extern tree nonlocal_labels;
#endif
#define NO_DEFER_POP (inhibit_defer_pop += 1)
#define OK_DEFER_POP (inhibit_defer_pop -= 1)
/* Number of units that we should eventually pop off the stack.
These are the arguments to function calls that have already returned. */
extern int pending_stack_adjust;
......
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