From: Martin Sebor Date: Tue, 19 Mar 2019 17:45:34 +0000 (+0000) Subject: PR tree-optimization/89644 - False-positive -Warray-bounds diagnostic on strncpy X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=e3ba46bd52f9bd6db8788384dd186c9ba5963129;p=gcc.git PR tree-optimization/89644 - False-positive -Warray-bounds diagnostic on strncpy gcc/ChangeLog: PR tree-optimization/89644 * tree-ssa-strlen.c (handle_builtin_stxncpy): Consider unterminated arrays in determining sequence sizes in strncpy and stpncpy. gcc/testsuite/ChangeLog: PR tree-optimization/89644 * gcc.dg/Wstringop-truncation-8.c: New test. From-SVN: r269807 --- diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 750d5e67cfd..fe1f0640e7f 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,9 @@ +2019-03-19 Martin Sebor + + PR tree-optimization/89644 + * tree-ssa-strlen.c (handle_builtin_stxncpy): Consider unterminated + arrays in determining sequence sizes in strncpy and stpncpy. + 2019-03-19 Martin Liska PR middle-end/89737 diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index 86cc80b3d37..cf01b2fea19 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,3 +1,8 @@ +2019-03-19 Martin Sebor + + PR tree-optimization/89644 + * gcc.dg/Wstringop-truncation-8.c: New test. + 2019-03-19 Martin Liska PR middle-end/89737 diff --git a/gcc/testsuite/gcc.dg/Wstringop-truncation-8.c b/gcc/testsuite/gcc.dg/Wstringop-truncation-8.c new file mode 100644 index 00000000000..1745da50a37 --- /dev/null +++ b/gcc/testsuite/gcc.dg/Wstringop-truncation-8.c @@ -0,0 +1,94 @@ +/* PR tree-optimization/89644 - False-positive -Warray-bounds diagnostic + on strncpy + { dg-do compile } + { dg-options "-O2 -Wall -ftrack-macro-expansion=0" } */ + +#define NONSTR __attribute__ ((nonstring)) + +typedef __SIZE_TYPE__ size_t; + +size_t strlen (const char*); +extern char* stpncpy (char*, const char*, size_t); +extern char* strncpy (char*, const char*, size_t); + +void sink (char*, ...); + +char f0 (char *s) +{ + char a[6] NONSTR = { 1, 2, 3, 4, 5, 6 }; + if (*s) + strncpy (a, s, sizeof a); /* { dg-bogus "\\\[-Warray-bounds" } */ + return a[0]; +} + +void f1 (char *s) +{ + char a[6] NONSTR = { 1, 2, 3, 4, 5, 6 }; + if (*s) + strncpy (a, s, sizeof a); /* { dg-bogus "\\\[-Warray-bounds" } */ + sink (a); +} + +char f2 (void) +{ + char a[6] NONSTR = { 1, 2, 3, 4, 5, 6 }; + char b[6] NONSTR = { 6, 5, 4, 3, 2, 1 }; + strncpy (a, b + 1, 5); /* { dg-bogus "\\\[-Warray-bounds" } */ + return a[0]; +} + +void f3 (void) +{ + char a[6] NONSTR = { 1, 2, 3, 4, 5, 6 }; + char b[6] NONSTR = { 6, 5, 4, 3, 2, 1 }; + strncpy (a, b + 2, 4); /* { dg-bogus "\\\[-Warray-bounds" } */ + sink (a); +} + +void f4 (NONSTR char *d) +{ + char b[6] NONSTR = { 6, 5, 4, 3, 2, 1 }; + strncpy (d, b + 3, 3); /* { dg-bogus "\\\[-Warray-bounds" } */ + sink (d); +} + + +char g0 (char *s) +{ + char a[6] NONSTR = { 1, 2, 3, 4, 5, 6 }; + if (*s) + stpncpy (a, s, sizeof a); /* { dg-bogus "\\\[-Warray-bounds" } */ + return a[0]; +} + +void g1 (char *s) +{ + char a[6] NONSTR = { 1, 2, 3, 4, 5, 6 }; + char *p = 0; + if (*s) + p = stpncpy (a, s, sizeof a); /* { dg-bogus "\\\[-Warray-bounds" } */ + sink (a, p); +} + +char g2 (void) +{ + char a[6] NONSTR = { 1, 2, 3, 4, 5, 6 }; + char b[6] NONSTR = { 6, 5, 4, 3, 2, 1 }; + stpncpy (a, b + 1, 5); /* { dg-bogus "\\\[-Warray-bounds" } */ + return a[0]; +} + +void g3 (void) +{ + char a[6] NONSTR = { 1, 2, 3, 4, 5, 6 }; + char b[6] NONSTR = { 6, 5, 4, 3, 2, 1 }; + char *p = stpncpy (a, b + 2, 4); /* { dg-bogus "\\\[-Warray-bounds" } */ + sink (a, p); +} + +void g4 (NONSTR char *d) +{ + char b[6] NONSTR = { 6, 5, 4, 3, 2, 1 }; + char *p = stpncpy (d, b + 3, 3); /* { dg-bogus "\\\[-Warray-bounds" } */ + sink (d, p); +} diff --git a/gcc/tree-ssa-strlen.c b/gcc/tree-ssa-strlen.c index 1eaed666ef2..cf0f70d9d7f 100644 --- a/gcc/tree-ssa-strlen.c +++ b/gcc/tree-ssa-strlen.c @@ -2206,13 +2206,21 @@ handle_builtin_stxncpy (built_in_function, gimple_stmt_iterator *gsi) int didx = get_stridx (dst); if (strinfo *sidst = didx > 0 ? get_strinfo (didx) : NULL) { - /* Compute the size of the destination string including the NUL. */ + /* Compute the size of the destination string including the nul + if it is known to be nul-terminated. */ if (sidst->nonzero_chars) { - tree type = TREE_TYPE (sidst->nonzero_chars); - dstsize = fold_build2 (PLUS_EXPR, type, sidst->nonzero_chars, - build_int_cst (type, 1)); + if (sidst->endptr) + { + /* String is known to be nul-terminated. */ + tree type = TREE_TYPE (sidst->nonzero_chars); + dstsize = fold_build2 (PLUS_EXPR, type, sidst->nonzero_chars, + build_int_cst (type, 1)); + } + else + dstsize = sidst->nonzero_chars; } + dst = sidst->ptr; } @@ -2224,12 +2232,18 @@ handle_builtin_stxncpy (built_in_function, gimple_stmt_iterator *gsi) over the terminating nul so SISRC->DONT_INVALIDATE must be left clear. */ - /* Compute the size of the source string including the NUL. */ + /* Compute the size of the source string including the terminating + nul if its known to be nul-terminated. */ if (sisrc->nonzero_chars) { - tree type = TREE_TYPE (sisrc->nonzero_chars); - srcsize = fold_build2 (PLUS_EXPR, type, sisrc->nonzero_chars, - build_int_cst (type, 1)); + if (sisrc->endptr) + { + tree type = TREE_TYPE (sisrc->nonzero_chars); + srcsize = fold_build2 (PLUS_EXPR, type, sisrc->nonzero_chars, + build_int_cst (type, 1)); + } + else + srcsize = sisrc->nonzero_chars; } src = sisrc->ptr;