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arm: Allow TLS access with -mslow-flash-data #65

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arm: Allow TLS access with -mslow-flash-data #65

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33 changes: 24 additions & 9 deletions gcc/config/arm/arm.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -8724,6 +8724,19 @@ arm_legitimate_address_outer_p (machine_mode mode, rtx x, RTX_CODE outer,
return 0;
}

/* Return nonzero if literal pool is allowed for the constant X.
With -mslow-flash-data, literal pools are allowed specifically for TLS
access. With -mpure-code, literal pools are never allowed. */
static int
arm_literal_pool_allowed_p (rtx x)
{
if (!arm_disable_literal_pool)
return 1;
if (target_slow_flash_data && tls_mentioned_p (x))
return 1;
return 0;
}

/* Return true if we can avoid creating a constant pool entry for x. */
static bool
can_avoid_literal_pool_for_label_p (rtx x)
Expand All @@ -8743,8 +8756,9 @@ can_avoid_literal_pool_for_label_p (rtx x)
(set (reg r0) (mem (reg r0))).
No extra register is required, and (mem (reg r0)) won't cause the use
of literal pools. */
if (arm_disable_literal_pool && SYMBOL_REF_P (x)
&& CONSTANT_POOL_ADDRESS_P (x))
if (SYMBOL_REF_P (x)
&& CONSTANT_POOL_ADDRESS_P (x)
&& !arm_literal_pool_allowed_p (get_pool_constant (x)))
return 1;
return 0;
}
Expand Down Expand Up @@ -9130,7 +9144,7 @@ thumb1_legitimate_address_p (machine_mode mode, rtx x, int strict_p)
else if (GET_MODE_SIZE (mode) >= 4 && CONSTANT_P (x)
&& SYMBOL_REF_P (x)
&& CONSTANT_POOL_ADDRESS_P (x) && !flag_pic
&& !arm_disable_literal_pool)
&& arm_literal_pool_allowed_p (get_pool_constant (x)))
return 1;

/* This is PC relative data after arm_reorg runs. */
Expand Down Expand Up @@ -9196,7 +9210,7 @@ thumb1_legitimate_address_p (machine_mode mode, rtx x, int strict_p)
&& GET_MODE_SIZE (mode) == 4
&& SYMBOL_REF_P (x)
&& CONSTANT_POOL_ADDRESS_P (x)
&& !arm_disable_literal_pool
&& arm_literal_pool_allowed_p (get_pool_constant (x))
&& ! (flag_pic
&& symbol_mentioned_p (get_pool_constant (x))
&& ! pcrel_constant_p (get_pool_constant (x))))
Expand Down Expand Up @@ -9735,10 +9749,11 @@ arm_tls_referenced_p (rtx x)
{
/* ARM currently does not provide relocations to encode TLS variables
into AArch32 instructions, only data, so there is no way to
currently implement these if a literal pool is disabled. */
if (arm_disable_literal_pool)
currently implement these if a literal pool is disabled.
With -mslow-flash-data, we allow TLS by using the literal pool. */
if (target_pure_code)
sorry ("accessing thread-local storage is not currently supported "
"with %<-mpure-code%> or %<-mslow-flash-data%>");
"with %<-mpure-code%>");

return true;
}
Expand Down Expand Up @@ -18309,7 +18324,7 @@ static void
push_minipool_fix (rtx_insn *insn, HOST_WIDE_INT address, rtx *loc,
machine_mode mode, rtx value)
{
gcc_assert (!arm_disable_literal_pool);
gcc_assert (arm_literal_pool_allowed_p (value));
Mfix * fix = (Mfix *) obstack_alloc (&minipool_obstack, sizeof (* fix));

fix->insn = insn;
Expand Down Expand Up @@ -19630,7 +19645,7 @@ arm_reorg (void)

/* Make sure we do not attempt to create a literal pool even though it should
no longer be necessary to create any. */
if (arm_disable_literal_pool)
if (target_pure_code)
return ;

minipool_fix_head = minipool_fix_tail = NULL;
Expand Down