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gdb-symtab-work-around-pr-gas-29517.patch
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File gdb-symtab-work-around-pr-gas-29517.patch of Package gdb
From 92a5f5ae1b71d152d943ee896bf6cd073d50daa7 Mon Sep 17 00:00:00 2001 From: Tom de Vries <tdevries@suse.de> Date: Thu, 28 Sep 2023 13:55:07 +0200 Subject: [PATCH 02/12] [gdb/symtab] Work around PR gas/29517 When using glibc debuginfo generated with gas 2.39, we run into PR gas/29517: ... $ gdb -q -batch a.out -ex start -ex "p (char *)strstr (\"haha\", \"ah\")" Temporary breakpoint 1 at 0x40051b: file hello.c, line 6. Temporary breakpoint 1, main () at hello.c:6 6 printf ("hello\n"); Invalid cast. ... while without glibc debuginfo installed we get the expected result: ... $n = 0x7ffff7daa1b1 "aha" ... and likewise with glibc debuginfo generated with gas 2.40. The strstr ifunc resolves to __strstr_sse2_unaligned. The problem is that gas generates dwarf that states that the return type is void: ... <1><3e1e58>: Abbrev Number: 2 (DW_TAG_subprogram) <3e1e59> DW_AT_name : __strstr_sse2_unaligned <3e1e5d> DW_AT_external : 1 <3e1e5e> DW_AT_low_pc : 0xbbd2e <3e1e66> DW_AT_high_pc : 0xbc1c3 ... while the return type should be a DW_TAG_unspecified_type, as is the case with gas 2.40. We can still use the workaround of casting to another function type for both __strstr_sse2_unaligned: ... (gdb) p ((char * (*) (const char *, const char *))__strstr_sse2_unaligned) \ ("haha", "ah") $n = 0x7ffff7daa211 "aha" ... and strstr (which requires using *strstr to dereference the ifunc before we cast): ... gdb) p ((char * (*) (const char *, const char *))*strstr) ("haha", "ah") $n = 0x7ffff7daa251 "aha" ... but that's a bit cumbersome to use. Work around this in the dwarf reader, such that we have instead: ... (gdb) p (char *)strstr ("haha", "ah") $n = 0x7ffff7daa1b1 "aha" ... This also requires fixing producer_is_gcc to stop returning true for producer "GNU AS 2.39.0". Tested on x86_64-linux. PR symtab/30911 Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=30911 --- gdb/dwarf2/cu.c | 1 + gdb/dwarf2/cu.h | 1 + gdb/dwarf2/read.c | 22 ++++++++++++ gdb/producer.c | 8 ++++- .../gdb.dwarf2/dw2-unspecified-type.c | 9 ++++- .../gdb.dwarf2/dw2-unspecified-type.exp | 36 +++++++++++++++---- 6 files changed, 68 insertions(+), 9 deletions(-) diff --git a/gdb/dwarf2/cu.c b/gdb/dwarf2/cu.c index 9c1691c90e9..42fd4f4441b 100644 --- a/gdb/dwarf2/cu.c +++ b/gdb/dwarf2/cu.c @@ -40,6 +40,7 @@ dwarf2_cu::dwarf2_cu (dwarf2_per_cu_data *per_cu, producer_is_icc_lt_14 (false), producer_is_codewarrior (false), producer_is_clang (false), + producer_is_gas_2_39 (false), processing_has_namespace_info (false), load_all_dies (false) { diff --git a/gdb/dwarf2/cu.h b/gdb/dwarf2/cu.h index e8dbde9c019..710aeb5b237 100644 --- a/gdb/dwarf2/cu.h +++ b/gdb/dwarf2/cu.h @@ -265,6 +265,7 @@ struct dwarf2_cu bool producer_is_icc_lt_14 : 1; bool producer_is_codewarrior : 1; bool producer_is_clang : 1; + bool producer_is_gas_2_39 : 1; /* When true, the file that we're processing is known to have debugging info for C++ namespaces. GCC 3.3.x did not produce diff --git a/gdb/dwarf2/read.c b/gdb/dwarf2/read.c index b9e7e18f2a6..f39eba7a008 100644 --- a/gdb/dwarf2/read.c +++ b/gdb/dwarf2/read.c @@ -13370,6 +13370,8 @@ check_producer (struct dwarf2_cu *cu) cu->producer_is_codewarrior = true; else if (producer_is_clang (cu->producer, &major, &minor)) cu->producer_is_clang = true; + else if (startswith (cu->producer, "GNU AS 2.39.0")) + cu->producer_is_gas_2_39 = true; else { /* For other non-GCC compilers, expect their behavior is DWARF version @@ -13405,6 +13407,15 @@ producer_is_codewarrior (struct dwarf2_cu *cu) return cu->producer_is_codewarrior; } +static bool +producer_is_gas_2_39 (struct dwarf2_cu *cu) +{ + if (!cu->checked_producer) + check_producer (cu); + + return cu->producer_is_gas_2_39; +} + /* Return the accessibility of DIE, as given by DW_AT_accessibility. If that attribute is not available, return the appropriate default. */ @@ -16581,6 +16592,17 @@ read_subroutine_type (struct die_info *die, struct dwarf2_cu *cu) type = die_type (die, cu); + if (type->code () == TYPE_CODE_VOID + && !type->is_stub () + && die->child == nullptr + && producer_is_gas_2_39 (cu)) + { + /* Work around PR gas/29517, pretend we have an DW_TAG_unspecified_type + return type. */ + type = init_type (cu->per_objfile->objfile, TYPE_CODE_VOID, 0, NULL); + type->set_is_stub (true); + } + /* The die_type call above may have already set the type for this DIE. */ ftype = get_die_type (die, cu); if (ftype) diff --git a/gdb/producer.c b/gdb/producer.c index 655eb971283..9fcf749e3d4 100644 --- a/gdb/producer.c +++ b/gdb/producer.c @@ -54,13 +54,19 @@ producer_is_gcc (const char *producer, int *major, int *minor) if (minor == NULL) minor = &min; + /* Skip GNU. */ + cs = &producer[strlen ("GNU ")]; + + /* Bail out for GNU AS. */ + if (startswith (cs, "AS ")) + return 0; + /* Skip any identifier after "GNU " - such as "C11" "C++" or "Java". A full producer string might look like: "GNU C 4.7.2" "GNU Fortran 4.8.2 20140120 (Red Hat 4.8.2-16) -mtune=generic ..." "GNU C++14 5.0.0 20150123 (experimental)" */ - cs = &producer[strlen ("GNU ")]; while (*cs && !isspace (*cs)) cs++; if (*cs && isspace (*cs)) diff --git a/gdb/testsuite/gdb.dwarf2/dw2-unspecified-type.c b/gdb/testsuite/gdb.dwarf2/dw2-unspecified-type.c index 1df09214d4a..e07d9517ff2 100644 --- a/gdb/testsuite/gdb.dwarf2/dw2-unspecified-type.c +++ b/gdb/testsuite/gdb.dwarf2/dw2-unspecified-type.c @@ -17,9 +17,16 @@ extern int foo (void); +int +bar (void) +{ + asm ("bar_label: .globl bar_label"); + return 0; +} + int main (void) { - int res = foo (); + int res = foo () + bar (); return res; } diff --git a/gdb/testsuite/gdb.dwarf2/dw2-unspecified-type.exp b/gdb/testsuite/gdb.dwarf2/dw2-unspecified-type.exp index a353395592e..bd707204fba 100644 --- a/gdb/testsuite/gdb.dwarf2/dw2-unspecified-type.exp +++ b/gdb/testsuite/gdb.dwarf2/dw2-unspecified-type.exp @@ -29,10 +29,18 @@ lassign $foo_res \ foo_start foo_len set foo_end "$foo_start + $foo_len" +set bar_res \ + [function_range bar \ + [list ${srcdir}/${subdir}/$srcfile ${srcdir}/${subdir}/$srcfile2]] +lassign $bar_res \ + bar_start bar_len +set bar_end "$bar_start + $bar_len" + # Create the DWARF. set asm_file [standard_output_file $srcfile3] Dwarf::assemble $asm_file { global foo_start foo_end + global bar_start bar_end declare_labels unspecified_type_label cu {} { @@ -47,7 +55,19 @@ Dwarf::assemble $asm_file { {high_pc $foo_end addr} {type :$unspecified_type_label} } + } + } + cu {} { + compile_unit { + {language @DW_LANG_Mips_Assembler} + {producer "GNU AS 2.39.0"} + } { + DW_TAG_subprogram { + {name bar} + {low_pc $bar_start addr} + {high_pc $bar_end addr} + } } } } @@ -61,12 +81,14 @@ if ![runto_main] { return -1 } -# Print the function type. Return type should be stub type, which is printed -# as void. -gdb_test "ptype foo" "type = void \\(void\\)" +foreach f {foo bar} { + # Print the function type. Return type should be stub type, which is printed + # as void. + gdb_test "ptype $f" "type = void \\(void\\)" -# Call the function, casting the function to the correct function type. -gdb_test "p ((int (*) ()) foo) ()" " = 0" + # Call the function, casting the function to the correct function type. + gdb_test "p ((int (*) ()) $f) ()" " = 0" -# Call the function, casting the function result to the correct type. -gdb_test "p (int) foo ()" " = 0" + # Call the function, casting the function result to the correct type. + gdb_test "p (int) $f ()" " = 0" +} -- 2.35.3
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