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[86.164.199.62]) by smtp.gmail.com with ESMTPSA id z62-v6sm3167551wmc.10.2018.07.04.11.13.04 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Wed, 04 Jul 2018 11:13:04 -0700 (PDT) From: Andrew Burgess To: gdb-patches@sourceware.org Cc: Andrew Burgess Subject: [PATCH] gdb/testsuite: Allow for failure to read some memory addresses Date: Wed, 4 Jul 2018 19:13:02 +0100 Message-Id: <20180704181302.5364-1-andrew.burgess@embecosm.com> X-IsSubscribed: yes In the gdb.base/examine-backward.exp test script, we check to see if address zero is readable, and then read memory first forward from address zero, and then backward from address zero. The problem is, being able to read address zero does not guarantee that you'll be able to read from the other end of the address space, and the test probably shouldn't assume that is the case. This patch extends the success conditions so that, even if GDB fails to read memory, so long as the error message indicates that GDB was trying to access the correct location, then we consider this a pass. The test is, I think, trying to show that GDB can compute the correct address when going backward from zero, being able to access the memory at that address is secondary. One further change is that, when we examined the memory at address zero, the regexp used to match the address expected that the zero address would have two '0' digits as the least significant digits. As GDB strips leading zeros from addresses this was causing the test to fail. I've reduced the zero address to a single 0 digit. gdb/testsuite/ChangeLog: * gdb.base/examine-backward.exp: Be more forgiving of failures to read some addresses. Update zero address pattern. --- gdb/testsuite/ChangeLog | 5 ++++ gdb/testsuite/gdb.base/examine-backward.exp | 42 ++++++++++++++++++++++++----- 2 files changed, 40 insertions(+), 7 deletions(-) diff --git a/gdb/testsuite/gdb.base/examine-backward.exp b/gdb/testsuite/gdb.base/examine-backward.exp index be80b841aa..a47e3507c3 100644 --- a/gdb/testsuite/gdb.base/examine-backward.exp +++ b/gdb/testsuite/gdb.base/examine-backward.exp @@ -83,18 +83,46 @@ with_test_prefix "memory page boundary" { } with_test_prefix "address zero boundary" { + global gdb_prompt + if {[is_address_zero_readable]} { set address_zero "0x0" set byte "\t0x\[0-9a-f\]+" gdb_test "x/3xb ${address_zero}" \ - "0x\[0-9a-f\]+00.*:${byte}${byte}${byte}" \ + "0x\[0-9a-f\]*0.*:${byte}${byte}${byte}" \ "examine 3 bytes forward from ${address_zero}" - gdb_test "x/-6x" \ - "0x\[0-9a-f\]+fd.*:${byte}${byte}${byte}${byte}${byte}${byte}" \ - "examine 6 bytes backward" - gdb_test "x/-3x ${address_zero}" \ - "0x\[0-9a-f\]+fd.*:${byte}${byte}${byte}" \ - "examine 3 bytes backward from ${address_zero}" + + set test "examine 6 bytes backward" + gdb_test_multiple "x/-6x" "$test" { + -re "0x\[0-9a-f\]+fd.*:${byte}${byte}${byte}${byte}${byte}${byte}.*\[\r\n\]*$gdb_prompt $" { + pass $test + } + -re "0x\[0-9a-f\]+fd.*:\tCannot access memory at address 0x\[0-9a-f\]+fd.*\[\r\n\]*$gdb_prompt $" { + # We test that we can read zero, but that's no + # guarantee that we can read from the other end of the + # address space. If we get an error about trying to + # read from the expected address then we count that as + # a pass, GDB did try to read the correct location. + pass $test + } + -re "$gdb_prompt $" { + fail $test + } + } + + set test "examine 3 bytes backward from ${address_zero}" + gdb_test_multiple "x/-3x ${address_zero}" "$test" { + -re "0x\[0-9a-f\]+fd.*:${byte}${byte}${byte}${byte}${byte}${byte}.*\[\r\n\]*$gdb_prompt $" { + pass $test + } + -re "0x\[0-9a-f\]+fd.*:\tCannot access memory at address 0x\[0-9a-f\]+fd.*\[\r\n\]*$gdb_prompt $" { + # See previous test for why this is a pass. + pass $test + } + -re "$gdb_prompt $" { + fail $test + } + } } }