Contrary to CTF and our previous expectations, as per [1], turns out that in BTF:
1) The `encoding' field in integer types shall not be treated as a bitmap, but as an enumerated, i.e. these bits are exclusive to each other. 2) The CHAR bit in `encoding' shall _not_ be set when emitting types for char nor `unsigned char'. Consequently this patch clears the CHAR bit before emitting the variable part of BTF integral types. It also updates the testsuite accordingly, expanding it to check for BOOL bits. [1] https://lore.kernel.org/bpf/a73586ad-f2dc-0401-1eba-2004357b7...@fb.com/T/#t gcc/ChangeLog: * btfout.cc (output_asm_btf_vlen_bytes): Do not use the CHAR encoding bit in BTF. gcc/testsuite/ChangeLog: * gcc.dg/debug/btf/btf-int-1.c: Do not check for char bits in bti_encoding and check for bool bits. --- gcc/btfout.cc | 4 ++++ gcc/testsuite/gcc.dg/debug/btf/btf-int-1.c | 18 +++++++++++------- 2 files changed, 15 insertions(+), 7 deletions(-) diff --git a/gcc/btfout.cc b/gcc/btfout.cc index 31af50521da..576f73d47cf 100644 --- a/gcc/btfout.cc +++ b/gcc/btfout.cc @@ -914,6 +914,10 @@ output_asm_btf_vlen_bytes (ctf_container_ref ctfc, ctf_dtdef_ref dtd) if (dtd->dtd_data.ctti_size < 1) break; + /* In BTF the CHAR `encoding' seems to not be used, so clear it + here. */ + dtd->dtd_u.dtu_enc.cte_format &= ~BTF_INT_CHAR; + encoding = BTF_INT_DATA (dtd->dtd_u.dtu_enc.cte_format, dtd->dtd_u.dtu_enc.cte_offset, dtd->dtd_u.dtu_enc.cte_bits); diff --git a/gcc/testsuite/gcc.dg/debug/btf/btf-int-1.c b/gcc/testsuite/gcc.dg/debug/btf/btf-int-1.c index 2381decd6ff..87d9758e9cb 100644 --- a/gcc/testsuite/gcc.dg/debug/btf/btf-int-1.c +++ b/gcc/testsuite/gcc.dg/debug/btf/btf-int-1.c @@ -4,7 +4,8 @@ | 0 | encoding | offset | 00 | bits | encoding: signed 1 << 24 - char 2 << 24 + char 2 << 24 (not used) + bool 4 << 24 All offsets in this test should be 0. This test does _not_ check number of bits, as it may vary between targets. @@ -13,13 +14,14 @@ /* { dg-do compile } */ /* { dg-options "-O0 -gbtf -dA" } */ -/* Check for 8 BTF_KIND_INT types. */ -/* { dg-final { scan-assembler-times "\[\t \]0x1000000\[\t \]+\[^\n\]*btt_info" 8 } } */ +/* Check for 9 BTF_KIND_INT types. */ +/* { dg-final { scan-assembler-times "\[\t \]0x1000000\[\t \]+\[^\n\]*btt_info" 9 } } */ -/* Check the signed/char flags, but not bit size. */ -/* { dg-final { scan-assembler-times "\[\t \]0x10000..\[\t \]+\[^\n\]*bti_encoding" 3 } } */ -/* { dg-final { scan-assembler-times "\[\t \]0x20000..\[\t \]+\[^\n\]*bti_encoding" 1 } } */ -/* { dg-final { scan-assembler-times "\[\t \]0x30000..\[\t \]+\[^\n\]*bti_encoding" 1 } } */ +/* Check the signed flags, but not bit size. */ +/* { dg-final { scan-assembler-times "\[\t \]0x10000..\[\t \]+\[^\n\]*bti_encoding" 4 } } */ +/* { dg-final { scan-assembler-times "\[\t \]0x..\[\t \]+\[^\n\]*bti_encoding" 3 } } */ +/* { dg-final { scan-assembler-times "\[\t \]0x.\[\t \]+\[^\n\]*bti_encoding" 1 } } */ +/* { dg-final { scan-assembler-times "\[\t \]0x40000..\[\t \]+\[^\n\]*bti_encoding" 1 } } */ /* Check that there is a string entry for each type name. */ /* { dg-final { scan-assembler-times "ascii \"unsigned char.0\"\[\t \]+\[^\n\]*btf_string" 1 } } */ @@ -42,3 +44,5 @@ signed int f = -66; unsigned long int g = 77; signed long int h = 88; + +_Bool x = 1; -- 2.11.0
