From 8bf7fdfc16f5d5fd9a94c233c0c41d307ba86cd2 Mon Sep 17 00:00:00 2001 From: Tom de Vries Date: Tue, 21 Nov 2023 13:15:29 +0100 Subject: [PATCH 04/48] [gdb/testsuite] Fix spurious FAILs with examine-backward.exp, again Commit 59a561480d5 ("Fix spurious FAILs with examine-backward.exp") describes the problem that: ... The test case examine-backward.exp issues the command "x/-s" after the end of the first string in TestStrings, but without making sure that this string is preceded by a string terminator. Thus GDB may spuriously print some random characters from before that string, and then the test fails. ... The commit fixes the problem by adding a Barrier variable before the TestStrings variable: ... +const char Barrier[] = { 0x0 }; const char TestStrings[] = { ... There is however no guarantee that Barrier is placed immediately before TestStrings. Before recent commit 169fe7ab54b ("Change gdb.base/examine-backwards.exp for AIX.") on x86_64-linux, I see: ... 0000000000400660 R Barrier 0000000000400680 R TestStrings ... So while the Barrier variable is the first before the TestStrings variable, it's not immediately preceding TestStrings. After commit 169fe7ab54b: ... 0000000000402259 B Barrier 0000000000402020 D TestStrings ... they're not even in the same section anymore. Fix this reliably by adding the zero in the array itself: ... char TestStringsBase[] = { 0x0, ... }; char *TestStrings = &TestStringsBase[1]; ... and do likewise for TestStringsH and TestStringsW. Tested on x86_64-linux. PR testsuite/31064 Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=31064 --- gdb/testsuite/gdb.base/examine-backward.c | 35 ++++++++++++++------- gdb/testsuite/gdb.base/examine-backward.exp | 18 +++++------ 2 files changed, 33 insertions(+), 20 deletions(-) diff --git a/gdb/testsuite/gdb.base/examine-backward.c b/gdb/testsuite/gdb.base/examine-backward.c index 354c2e2f323..5549cc20a4a 100644 --- a/gdb/testsuite/gdb.base/examine-backward.c +++ b/gdb/testsuite/gdb.base/examine-backward.c @@ -32,15 +32,12 @@ literals. The content of each array is the same as followings: }; */ -/* This is here just to ensure we have a null character before - TestStrings, to avoid showing garbage when we look for strings - backwards from TestStrings. */ +unsigned char TestStringsBase[] = { + /* This is here just to ensure we have a null character before + TestStrings, to avoid showing garbage when we look for strings + backwards from TestStrings. */ + 0x0, -unsigned char Barrier[] = { - 0x00, -}; - -unsigned char TestStrings[] = { 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48, 0x49, 0x4a, 0x4b, 0x4c, 0x4d, 0x4e, 0x4f, 0x50, 0x51, 0x52, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58, @@ -54,7 +51,14 @@ unsigned char TestStrings[] = { 0x00 }; -short TestStringsH[] = { +unsigned char *TestStrings = &TestStringsBase[1]; + +short TestStringsHBase[] = { + /* This is here just to ensure we have a null character before + TestStringsH, to avoid showing garbage when we look for strings + backwards from TestStringsH. */ + 0x0, + 0x0041, 0x0042, 0x0043, 0x0044, 0x0045, 0x0046, 0x0047, 0x0048, 0x0049, 0x004a, 0x004b, 0x004c, 0x004d, 0x004e, 0x004f, 0x0050, 0x0051, 0x0052, 0x0053, 0x0054, 0x0055, 0x0056, 0x0057, 0x0058, @@ -67,7 +71,14 @@ short TestStringsH[] = { 0x0000 }; -int TestStringsW[] = { +short *TestStringsH = &TestStringsHBase[1]; + +int TestStringsWBase[] = { + /* This is here just to ensure we have a null character before + TestStringsW, to avoid showing garbage when we look for strings + backwards from TestStringsW. */ + 0x0, + 0x00000041, 0x00000042, 0x00000043, 0x00000044, 0x00000045, 0x00000046, 0x00000047, 0x00000048, 0x00000049, 0x0000004a, 0x0000004b, 0x0000004c, @@ -89,11 +100,13 @@ int TestStringsW[] = { 0x00000000 }; +int *TestStringsW = &TestStringsWBase[1]; + int main (void) { /* Clang++ eliminates the variables if nothing references them. */ - int dummy = Barrier[0] + TestStrings[0] + TestStringsH[0] + TestStringsW[0]; + int dummy = TestStrings[0] + TestStringsH[0] + TestStringsW[0]; /* Backward disassemble test requires at least 20 instructions in this function. Adding a simple bubble sort. */ diff --git a/gdb/testsuite/gdb.base/examine-backward.exp b/gdb/testsuite/gdb.base/examine-backward.exp index 7c8a08c0726..4e197d7d725 100644 --- a/gdb/testsuite/gdb.base/examine-backward.exp +++ b/gdb/testsuite/gdb.base/examine-backward.exp @@ -145,7 +145,7 @@ gdb_test_no_output "set charset ASCII" with_test_prefix "char-width=1, print-max=20" { gdb_test_no_output "set print elements 20" - gdb_test_sequence "x/6s &TestStrings" "take 6 strings forward" { + gdb_test_sequence "x/6s TestStrings" "take 6 strings forward" { "\"ABCDEFGHIJKLMNOPQRST\"\.\.\." "\"UVWXYZ\"" "\"\"" @@ -162,7 +162,7 @@ with_test_prefix "char-width=1, print-max=20" { "\"[^\"]+\"" "\"01234567890123456789\"\.\.\." } - gdb_test_sequence "x/6s &TestStrings" "take 6 strings forward again" { + gdb_test_sequence "x/6s TestStrings" "take 6 strings forward again" { "\"ABCDEFGHIJKLMNOPQRST\"\.\.\." "\"UVWXYZ\"" "\"\"" @@ -187,7 +187,7 @@ with_test_prefix "char-width=1, print-max=20" { with_test_prefix "char-width=2, print-max=20" { gdb_test_no_output "set print elements 20" - gdb_test_sequence "x/6sh &TestStringsH" "take 6 strings forward" { + gdb_test_sequence "x/6sh TestStringsH" "take 6 strings forward" { "u\"ABCDEFGHIJKLMNOPQRST\"\.\.\." "u\"UVWXYZ\"" "u\"\"" @@ -204,7 +204,7 @@ with_test_prefix "char-width=2, print-max=20" { "u\"[^\"]+\"" "u\"01234567890123456789\"\.\.\." } - gdb_test_sequence "x/6sh &TestStringsH" "take 6 strings forward again" { + gdb_test_sequence "x/6sh TestStringsH" "take 6 strings forward again" { "u\"ABCDEFGHIJKLMNOPQRST\"\.\.\." "u\"UVWXYZ\"" "u\"\"" @@ -229,7 +229,7 @@ with_test_prefix "char-width=2, print-max=20" { with_test_prefix "char-width=4, print-max=20" { gdb_test_no_output "set print elements 20" - gdb_test_sequence "x/6sw &TestStringsW" "take 6 strings forward" { + gdb_test_sequence "x/6sw TestStringsW" "take 6 strings forward" { "U\"ABCDEFGHIJKLMNOPQRST\"\.\.\." "U\"UVWXYZ\"" "U\"\"" @@ -246,7 +246,7 @@ with_test_prefix "char-width=4, print-max=20" { "U\"[^\"]+\"" "U\"01234567890123456789\"\.\.\." } - gdb_test_sequence "x/6sw &TestStringsW" "take 6 strings forward again" { + gdb_test_sequence "x/6sw TestStringsW" "take 6 strings forward again" { "U\"ABCDEFGHIJKLMNOPQRST\"\.\.\." "U\"UVWXYZ\"" "U\"\"" @@ -271,7 +271,7 @@ with_test_prefix "char-width=4, print-max=20" { with_test_prefix "char-width=2, print-max=0" { gdb_test_no_output "set print elements 0" - gdb_test_sequence "x/6sh &TestStringsH" "take 6 strings forward" { + gdb_test_sequence "x/6sh TestStringsH" "take 6 strings forward" { "u\"ABCDEFGHIJKLMNOPQRSTUVWXYZ\"" "u\"\"" "u\"\"" @@ -289,7 +289,7 @@ with_test_prefix "char-width=2, print-max=0" { "u\"012345678901234567890123456789\"" "u\"!!!!!!\"" } - gdb_test_sequence "x/6sh &TestStringsH" "take 6 strings forward again" { + gdb_test_sequence "x/6sh TestStringsH" "take 6 strings forward again" { "u\"ABCDEFGHIJKLMNOPQRSTUVWXYZ\"" "u\"\"" "u\"\"" @@ -314,7 +314,7 @@ with_test_prefix "char-width=2, print-max=0" { with_test_prefix "char-width=1, print-max=4" { gdb_test_no_output "set print elements 4" - gdb_test_sequence "x/9s &TestStrings" "take 9 strings forward" { + gdb_test_sequence "x/9s TestStrings" "take 9 strings forward" { "\"ABCD\"\.\.\." "\"EFGH\"\.\.\." "\"IJKL\"\.\.\." -- 2.35.3