extend.texi (Extended Asm): Clarify that overlap between asm-declared register variables used in an asm and...
* doc/extend.texi (Extended Asm): Clarify that overlap between asm-declared register variables used in an asm and the asm clobber list is not allowed. * stmt.c (decl_conflicts_with_clobbers_p): New function. (expand_asm_operands): Keep track of clobbered registers. Call decl_conflicts_with_clobbers_p for each input and output operand. If no conflicts found before, also do conflict sanity check when emitting clobbers. From-SVN: r57437
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Hans-Peter Nilsson
Hans-Peter Nilsson
parent
ddf0fc7224
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acb5d088cb
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@ -1,3 +1,14 @@
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2002-09-23 Hans-Peter Nilsson <hp@axis.com>
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* doc/extend.texi (Extended Asm): Clarify that overlap between
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asm-declared register variables used in an asm and the asm clobber
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list is not allowed.
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* stmt.c (decl_conflicts_with_clobbers_p): New function.
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(expand_asm_operands): Keep track of clobbered registers. Call
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decl_conflicts_with_clobbers_p for each input and output operand.
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If no conflicts found before, also do conflict sanity check when
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emitting clobbers.
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2002-09-23 Richard Henderson <rth@redhat.com>
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* c-common.c (cpp_define_data_format): Remove.
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@ -3700,7 +3700,10 @@ asm volatile ("movc3 %0,%1,%2"
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You may not write a clobber description in a way that overlaps with an
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input or output operand. For example, you may not have an operand
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describing a register class with one member if you mention that register
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in the clobber list. There is no way for you to specify that an input
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in the clobber list. Variables declared to live in specific registers
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(@pxref{Explicit Reg Vars}), and used as asm input or output operands must
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have no part mentioned in the clobber description.
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There is no way for you to specify that an input
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operand is modified without also specifying it as an output
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operand. Note that if all the output operands you specify are for this
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purpose (and hence unused), you will then also need to specify
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74
gcc/stmt.c
74
gcc/stmt.c
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@ -398,6 +398,7 @@ static int n_occurrences PARAMS ((int, const char *));
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static bool parse_input_constraint PARAMS ((const char **, int, int, int,
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int, const char * const *,
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bool *, bool *));
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static bool decl_conflicts_with_clobbers_p PARAMS ((tree, const HARD_REG_SET));
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static void expand_goto_internal PARAMS ((tree, rtx, rtx));
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static int expand_fixup PARAMS ((tree, rtx, rtx));
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static rtx expand_nl_handler_label PARAMS ((rtx, rtx));
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@ -1400,6 +1401,42 @@ parse_input_constraint (constraint_p, input_num, ninputs, noutputs, ninout,
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return true;
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}
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/* Check for overlap between registers marked in CLOBBERED_REGS and
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anything inappropriate in DECL. Emit error and return TRUE for error,
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FALSE for ok. */
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static bool
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decl_conflicts_with_clobbers_p (decl, clobbered_regs)
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tree decl;
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const HARD_REG_SET clobbered_regs;
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{
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/* Conflicts between asm-declared register variables and the clobber
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list are not allowed. */
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if ((TREE_CODE (decl) == VAR_DECL || TREE_CODE (decl) == PARM_DECL)
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&& DECL_REGISTER (decl)
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&& REGNO (DECL_RTL (decl)) < FIRST_PSEUDO_REGISTER)
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{
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rtx reg = DECL_RTL (decl);
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unsigned int regno;
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for (regno = REGNO (reg);
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regno < (REGNO (reg)
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+ HARD_REGNO_NREGS (REGNO (reg), GET_MODE (reg)));
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regno++)
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if (TEST_HARD_REG_BIT (clobbered_regs, regno))
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{
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error ("asm-specifier for variable `%s' conflicts with asm clobber list",
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IDENTIFIER_POINTER (DECL_NAME (decl)));
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/* Reset registerness to stop multiple errors emitted for a
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single variable. */
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DECL_REGISTER (decl) = 0;
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return true;
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}
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}
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return false;
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}
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/* Generate RTL for an asm statement with arguments.
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STRING is the instruction template.
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OUTPUTS is a list of output arguments (lvalues); INPUTS a list of inputs.
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@ -1430,6 +1467,8 @@ expand_asm_operands (string, outputs, inputs, clobbers, vol, filename, line)
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int noutputs = list_length (outputs);
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int ninout;
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int nclobbers;
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HARD_REG_SET clobbered_regs;
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int clobber_conflict_found = 0;
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tree tail;
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int i;
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/* Vector of RTX's of evaluated output operands. */
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@ -1467,6 +1506,7 @@ expand_asm_operands (string, outputs, inputs, clobbers, vol, filename, line)
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/* Count the number of meaningful clobbered registers, ignoring what
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we would ignore later. */
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nclobbers = 0;
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CLEAR_HARD_REG_SET (clobbered_regs);
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for (tail = clobbers; tail; tail = TREE_CHAIN (tail))
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{
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const char *regname = TREE_STRING_POINTER (TREE_VALUE (tail));
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@ -1476,6 +1516,10 @@ expand_asm_operands (string, outputs, inputs, clobbers, vol, filename, line)
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++nclobbers;
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else if (i == -2)
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error ("unknown register name `%s' in `asm'", regname);
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/* Mark clobbered registers. */
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if (i >= 0)
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SET_HARD_REG_BIT (clobbered_regs, i);
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}
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clear_last_expr ();
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@ -1601,6 +1645,9 @@ expand_asm_operands (string, outputs, inputs, clobbers, vol, filename, line)
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inout_mode[ninout] = TYPE_MODE (type);
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inout_opnum[ninout++] = i;
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}
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if (decl_conflicts_with_clobbers_p (val, clobbered_regs))
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clobber_conflict_found = 1;
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}
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/* Make vectors for the expression-rtx, constraint strings,
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@ -1685,6 +1732,9 @@ expand_asm_operands (string, outputs, inputs, clobbers, vol, filename, line)
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ASM_OPERANDS_INPUT_CONSTRAINT_EXP (body, i)
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= gen_rtx_ASM_INPUT (TYPE_MODE (type), constraints[i + noutputs]);
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if (decl_conflicts_with_clobbers_p (val, clobbered_regs))
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clobber_conflict_found = 1;
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}
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/* Protect all the operands from the queue now that they have all been
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@ -1769,6 +1819,7 @@ expand_asm_operands (string, outputs, inputs, clobbers, vol, filename, line)
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{
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const char *regname = TREE_STRING_POINTER (TREE_VALUE (tail));
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int j = decode_reg_name (regname);
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rtx clobbered_reg;
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if (j < 0)
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{
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@ -1790,8 +1841,29 @@ expand_asm_operands (string, outputs, inputs, clobbers, vol, filename, line)
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}
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/* Use QImode since that's guaranteed to clobber just one reg. */
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clobbered_reg = gen_rtx_REG (QImode, j);
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/* Do sanity check for overlap between clobbers and respectively
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input and outputs that hasn't been handled. Such overlap
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should have been detected and reported above. */
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if (!clobber_conflict_found)
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{
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int opno;
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/* We test the old body (obody) contents to avoid tripping
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over the under-construction body. */
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for (opno = 0; opno < noutputs; opno++)
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if (reg_overlap_mentioned_p (clobbered_reg, output_rtx[opno]))
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internal_error ("asm clobber conflict with output operand");
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for (opno = 0; opno < ninputs - ninout; opno++)
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if (reg_overlap_mentioned_p (clobbered_reg,
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ASM_OPERANDS_INPUT (obody, opno)))
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internal_error ("asm clobber conflict with input operand");
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}
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XVECEXP (body, 0, i++)
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= gen_rtx_CLOBBER (VOIDmode, gen_rtx_REG (QImode, j));
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= gen_rtx_CLOBBER (VOIDmode, clobbered_reg);
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}
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insn = emit_insn (body);
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