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Fixed problem with BTF defining smaller enums.

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This patch fixes a BTF, which would become invalid when having
smaller then 4 byte definitions of enums.
For example, when using the __attribute__((mode(byte))) in the enum
definition.

Two problems were identified:
 - it would incorrectly create an entry for enum64 when the size of the
   enum was different then 4.
 - it would allocate less then 4 bytes for the value entry in BTF, in
   case the type was smaller.

BTF generated was validated against clang.

gcc/ChangeLog:
	* btfout.cc (btf_calc_num_vbytes): Fixed logic for enum64.
	(btf_asm_enum_const): Corrected logic for enum64 and smaller
	than 4 bytes values.

gcc/testsuite/ChangeLog:
	* gcc.dg/debug/btf/btf-enum-small.c: Added test.
This commit is contained in:
Cupertino Miranda 2023-11-10 14:02:30 +00:00
parent faf5b14858
commit 099b15e2bd
2 changed files with 31 additions and 3 deletions
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6
gcc/btfout.cc
View file

@ -299,7 +299,7 @@ btf_calc_num_vbytes (ctf_dtdef_ref dtd)
break;
case BTF_KIND_ENUM:
vlen_bytes += (dtd->dtd_data.ctti_size == 0x8)
vlen_bytes += (dtd->dtd_data.ctti_size > 4)
? vlen * sizeof (struct btf_enum64)
: vlen * sizeof (struct btf_enum);
break;
@ -914,8 +914,8 @@ btf_asm_enum_const (unsigned int size, ctf_dmdef_t * dmd, unsigned int idx)
{
dw2_asm_output_data (4, dmd->dmd_name_offset, "ENUM_CONST '%s' idx=%u",
dmd->dmd_name, idx);
if (size == 4)
dw2_asm_output_data (size, dmd->dmd_value, "bte_value");
if (size <= 4)
dw2_asm_output_data (size < 4 ? 4 : size, dmd->dmd_value, "bte_value");
else
{
dw2_asm_output_data (4, dmd->dmd_value & 0xffffffff, "bte_value_lo32");

28
gcc/testsuite/gcc.dg/debug/btf/btf-enum-small.c Normal file
View file

@ -0,0 +1,28 @@
/* Test BTF generation for small enums. */
/* { dg-do compile } */
/* { dg-options "-O2 -gbtf -dA" } */
/* { dg-final { scan-assembler-not "bte_value_lo32" } } */
/* { dg-final { scan-assembler-not "bte_value_hi32" } } */
/* { dg-final { scan-assembler-times "\[\t \]0x6000002\[\t \]+\[^\n\]*btt_info" 1 } } */
/* { dg-final { scan-assembler-times " ENUM_CONST 'eSMALL' idx=0" 1 } } */
/* { dg-final { scan-assembler-times " ENUM_CONST 'eSMALLY' idx=1" 1 } } */
/* { dg-final { scan-assembler-times "ascii \"eSMALL.0\"\[\t \]+\[^\n\]*btf_string" 1 } } */
/* { dg-final { scan-assembler-times "ascii \"eSMALLY.0\"\[\t \]+\[^\n\]*btf_string" 1 } } */
/* { dg-final { scan-assembler-times "bte_value" 2 } } */
enum smalled_enum
{
eSMALL,
eSMALLY,
} __attribute__((mode(byte)));
struct root_struct {
enum smalled_enum esmall;
};
enum smalled_enum
foo(struct root_struct *root) {
return root->esmall;
}