From 1d6ce4d31257e1ea49b3a1b257055bf8f7ff16af Mon Sep 17 00:00:00 2001 From: Yoshinori Sato Date: Tue, 19 May 2020 13:33:08 -0400 Subject: [PATCH] gdb: fix -Wtautological-overlap-compare error in h8300-tdep.c Compiling with clang 11 gives us: CXX h8300-tdep.o /home/smarchi/src/binutils-gdb/gdb/h8300-tdep.c:225:21: error: overlapping comparisons always evaluate to false [-Werror,-Wtautological-overlap-compare] if (disp < 0 && disp > 0xffffff) ~~~~~~~~~^~~~~~~~~~~~~~~~~~ /home/smarchi/src/binutils-gdb/gdb/h8300-tdep.c:203:17: error: overlapping comparisons always evaluate to false [-Werror,-Wtautological-overlap-compare] if (disp < 0 && disp > 0xffffff) ~~~~~~~~~^~~~~~~~~~~~~~~~~~ /home/smarchi/src/binutils-gdb/gdb/h8300-tdep.c:184:17: error: overlapping comparisons always evaluate to false [-Werror,-Wtautological-overlap-compare] if (disp < 0 && disp > 0xffffff) ~~~~~~~~~^~~~~~~~~~~~~~~~~~ Indeed, disp (of type LONGEST) can't be less than 0 and greater than 0xffffff. Fix it by changing the way we check if disp is negative. Check the sign bit of disp, which is a 24-bit number. gdb/ChangeLog: * h8300-tdep.c (h8300_is_argument_spill): Change how we check whether disp is negative. --- gdb/ChangeLog | 5 +++++ gdb/h8300-tdep.c | 13 +++++++------ 2 files changed, 12 insertions(+), 6 deletions(-) diff --git a/gdb/ChangeLog b/gdb/ChangeLog index f086b5cf908..c4393182dd9 100644 --- a/gdb/ChangeLog +++ b/gdb/ChangeLog @@ -1,3 +1,8 @@ +2020-05-19 Yoshinori Sato + + * h8300-tdep.c (h8300_is_argument_spill): Change how we check + whether disp is negative. + 2020-05-19 Simon Marchi * symfile.h (struct symfile_segment_data) diff --git a/gdb/h8300-tdep.c b/gdb/h8300-tdep.c index 3c2f502a124..b569a23f263 100644 --- a/gdb/h8300-tdep.c +++ b/gdb/h8300-tdep.c @@ -178,10 +178,10 @@ h8300_is_argument_spill (struct gdbarch *gdbarch, CORE_ADDR pc) if (IS_MOVB_Rn24_SP (read_memory_unsigned_integer (pc + 2, 2, byte_order))) { - LONGEST disp = read_memory_integer (pc + 4, 4, byte_order); + ULONGEST disp = read_memory_unsigned_integer (pc + 4, 4, byte_order); /* ... and d:24 is negative. */ - if (disp < 0 && disp > 0xffffff) + if ((disp & 0x00800000) != 0) return 8; } } @@ -197,10 +197,10 @@ h8300_is_argument_spill (struct gdbarch *gdbarch, CORE_ADDR pc) if (IS_MOVW_Rn24_SP (read_memory_unsigned_integer (pc + 2, 2, byte_order))) { - LONGEST disp = read_memory_integer (pc + 4, 4, byte_order); + ULONGEST disp = read_memory_unsigned_integer (pc + 4, 4, byte_order); /* ... and d:24 is negative. */ - if (disp < 0 && disp > 0xffffff) + if ((disp & 0x00800000) != 0) return 8; } } @@ -219,10 +219,11 @@ h8300_is_argument_spill (struct gdbarch *gdbarch, CORE_ADDR pc) { if (IS_MOVL_Rn24_SP (read_memory_integer (pc + 4, 2, byte_order))) { - LONGEST disp = read_memory_integer (pc + 6, 4, byte_order); + ULONGEST disp = read_memory_unsigned_integer (pc + 6, 4, + byte_order); /* ... and d:24 is negative. */ - if (disp < 0 && disp > 0xffffff) + if ((disp & 0x00800000) != 0) return 10; } } -- 2.30.2