| Message ID | HE1PR0701MB2860CD347E01C5780B077CF6E41F0@HE1PR0701MB2860.eurprd07.prod.outlook.com |
|---|---|
| State | New |
| Headers | show |
| Series | Cleanup strcpy/stpcpy no nul warning code | expand |
On 9/16/18 1:58 PM, Bernd Edlinger wrote: > Hi, > > this is a cleanup of the recently added strlen/strcpy/stpcpy > no nul warning code. > > Most importantly it moves the SSA_NAME handling from > unterminated_array to string_constant, thereby fixing > another round of xfails in the strlen and stpcpy test cases. > > I need to say that the fix for bug 86622 is relying in > type info on the pointer which is probably not safe in > GIMPLE in the light of the recent discussion. > > I had to add two further exceptions, which should > be safe in general: that is a pointer arithmentic on a string > literal is okay, and arithmetic on a string constant > that is exactly the size of the whole DECL, cannot > access an adjacent member. > > > Bootstrapped and reg-tested on x86_64-pc-linux-gnu. > Is it OK for trunk? > > > Thanks > Bernd. > > > patch-cleanup-no-nul.diff > > gcc: > 2018-09-16 Bernd Edlinger <bernd.edlinger@hotmail.de> > > * builtins.h (unterminated_array): Remove prototype. > * builtins.c (unterminated_array): Simplify. Make static. > (expand_builtin_strcpy_args): Don't use TREE_NO_WARNING here. > (expand_builtin_stpcpy_1): Remove warn_string_no_nul without effect. > * expr.c (string_constant): Handle SSA_NAME. Add more exceptions > where pointer arithmetic is safe. > * gimple-fold.c (get_range_strlen): Handle nonstr like in c_strlen. > (get_max_strlen): Remove the unnecessary mynonstr handling. > (gimple_fold_builtin_strcpy): Simplify. > (gimple_fold_builtin_stpcpy): Simplify. > (gimple_fold_builtin_sprintf): Remove NO_WARNING propagation > without effect. > (gimple_fold_builtin_strlen): Simplify. > > testsuite: > 2018-09-16 Bernd Edlinger <bernd.edlinger@hotmail.de> > > * gcc.dg/warn-stpcpy-no-nul.c: Remove xfails. > * gcc.dg/warn-strlen-no-nul.c: Remove xfails. > > Index: gcc/builtins.c > =================================================================== > --- gcc/builtins.c (revision 264342) > +++ gcc/builtins.c (working copy) > @@ -567,31 +567,12 @@ warn_string_no_nul (location_t loc, const char *fn > the declaration of the object of which the array is a member or > element. Otherwise return null. */ > > -tree > +static tree > unterminated_array (tree exp) > { > - if (TREE_CODE (exp) == SSA_NAME) > - { > - gimple *stmt = SSA_NAME_DEF_STMT (exp); > - if (!is_gimple_assign (stmt)) > - return NULL_TREE; > - > - tree rhs1 = gimple_assign_rhs1 (stmt); > - tree_code code = gimple_assign_rhs_code (stmt); > - if (code == ADDR_EXPR > - && TREE_CODE (TREE_OPERAND (rhs1, 0)) == ARRAY_REF) > - rhs1 = rhs1; > - else if (code != POINTER_PLUS_EXPR) > - return NULL_TREE; > - > - exp = rhs1; > - } > - > tree nonstr = NULL; > - if (c_strlen (exp, 1, &nonstr, 1) == NULL && nonstr) > - return nonstr; > - > - return NULL_TREE; > + c_strlen (exp, 1, &nonstr); > + return nonstr; > } Sigh. This is going to conflict with patch #6 from Martin's kit. > > /* Compute the length of a null-terminated character string or wide > @@ -3936,8 +3917,7 @@ expand_builtin_strcpy_args (tree exp, tree dest, t > if (tree nonstr = unterminated_array (src)) > { > /* NONSTR refers to the non-nul terminated constant array. */ > - if (!TREE_NO_WARNING (exp)) > - warn_string_no_nul (EXPR_LOCATION (exp), "strcpy", src, nonstr); > + warn_string_no_nul (EXPR_LOCATION (exp), "strcpy", src, nonstr); > return NULL_RTX; > } There's also some target dependencies to be concerned about. I'll have to dig out the thread, but in general removing these TREE_NO_WARNING checks is probably a bad idea -- you're likely introducing redundant warnings on one or more targets (but not x86). There may be things in there we want to take. But my focus is going to be on getting the #4 and #6 patches from Martin's kit resolved (while he works on the string length range stuff). Jeff
On 09/17/18 19:33, Jeff Law wrote: > On 9/16/18 1:58 PM, Bernd Edlinger wrote: >> Hi, >> >> this is a cleanup of the recently added strlen/strcpy/stpcpy >> no nul warning code. >> >> Most importantly it moves the SSA_NAME handling from >> unterminated_array to string_constant, thereby fixing >> another round of xfails in the strlen and stpcpy test cases. >> >> I need to say that the fix for bug 86622 is relying in >> type info on the pointer which is probably not safe in >> GIMPLE in the light of the recent discussion. >> >> I had to add two further exceptions, which should >> be safe in general: that is a pointer arithmentic on a string >> literal is okay, and arithmetic on a string constant >> that is exactly the size of the whole DECL, cannot >> access an adjacent member. >> >> >> Bootstrapped and reg-tested on x86_64-pc-linux-gnu. >> Is it OK for trunk? >> >> >> Thanks >> Bernd. >> >> >> patch-cleanup-no-nul.diff >> >> gcc: >> 2018-09-16 Bernd Edlinger <bernd.edlinger@hotmail.de> >> >> * builtins.h (unterminated_array): Remove prototype. >> * builtins.c (unterminated_array): Simplify. Make static. >> (expand_builtin_strcpy_args): Don't use TREE_NO_WARNING here. >> (expand_builtin_stpcpy_1): Remove warn_string_no_nul without effect. >> * expr.c (string_constant): Handle SSA_NAME. Add more exceptions >> where pointer arithmetic is safe. >> * gimple-fold.c (get_range_strlen): Handle nonstr like in c_strlen. >> (get_max_strlen): Remove the unnecessary mynonstr handling. >> (gimple_fold_builtin_strcpy): Simplify. >> (gimple_fold_builtin_stpcpy): Simplify. >> (gimple_fold_builtin_sprintf): Remove NO_WARNING propagation >> without effect. >> (gimple_fold_builtin_strlen): Simplify. >> >> testsuite: >> 2018-09-16 Bernd Edlinger <bernd.edlinger@hotmail.de> >> >> * gcc.dg/warn-stpcpy-no-nul.c: Remove xfails. >> * gcc.dg/warn-strlen-no-nul.c: Remove xfails. >> >> Index: gcc/builtins.c >> =================================================================== >> --- gcc/builtins.c (revision 264342) >> +++ gcc/builtins.c (working copy) >> @@ -567,31 +567,12 @@ warn_string_no_nul (location_t loc, const char *fn >> the declaration of the object of which the array is a member or >> element. Otherwise return null. */ >> >> -tree >> +static tree >> unterminated_array (tree exp) >> { >> - if (TREE_CODE (exp) == SSA_NAME) >> - { >> - gimple *stmt = SSA_NAME_DEF_STMT (exp); >> - if (!is_gimple_assign (stmt)) >> - return NULL_TREE; >> - >> - tree rhs1 = gimple_assign_rhs1 (stmt); >> - tree_code code = gimple_assign_rhs_code (stmt); >> - if (code == ADDR_EXPR >> - && TREE_CODE (TREE_OPERAND (rhs1, 0)) == ARRAY_REF) >> - rhs1 = rhs1; >> - else if (code != POINTER_PLUS_EXPR) >> - return NULL_TREE; >> - >> - exp = rhs1; >> - } >> - >> tree nonstr = NULL; >> - if (c_strlen (exp, 1, &nonstr, 1) == NULL && nonstr) >> - return nonstr; >> - >> - return NULL_TREE; >> + c_strlen (exp, 1, &nonstr); >> + return nonstr; >> } > Sigh. This is going to conflict with patch #6 from Martin's kit. > Sorry, it just feels wrong to do this folding here instead of in string_constant. I think the handling of POINTER_PLUS_EXPR above, is faulty, because it is ignoring the offset parameter, which typically contains the offset part, may add an offset to a different structure member or another array index. That is what happened in PR 86622. So you are likely looking at the wrong index, or even the wrong structure member. > >> >> /* Compute the length of a null-terminated character string or wide >> @@ -3936,8 +3917,7 @@ expand_builtin_strcpy_args (tree exp, tree dest, t >> if (tree nonstr = unterminated_array (src)) >> { >> /* NONSTR refers to the non-nul terminated constant array. */ >> - if (!TREE_NO_WARNING (exp)) >> - warn_string_no_nul (EXPR_LOCATION (exp), "strcpy", src, nonstr); >> + warn_string_no_nul (EXPR_LOCATION (exp), "strcpy", src, nonstr); >> return NULL_RTX; >> } > There's also some target dependencies to be concerned about. I'll have > to dig out the thread, but in general removing these TREE_NO_WARNING > checks is probably a bad idea -- you're likely introducing redundant > warnings on one or more targets (but not x86). > I just wondered why use if (!TREE_NO_WARNING(exp)) when warn_string_no_nul uses if (!TREE_NO_WARNING(src)), and sets TREE_NO_WARNING(src) on success. > > There may be things in there we want to take. But my focus is going to > be on getting the #4 and #6 patches from Martin's kit resolved (while he > works on the string length range stuff). > Oh, you are aware that I have a proposed patch on the string length range vs. gimple semantics here: https://gcc.gnu.org/ml/gcc-patches/2018-09/msg00805.html Bernd.
On 9/17/18 12:20 PM, Bernd Edlinger wrote: > On 09/17/18 19:33, Jeff Law wrote: >> On 9/16/18 1:58 PM, Bernd Edlinger wrote: >>> Hi, >>> >>> this is a cleanup of the recently added strlen/strcpy/stpcpy >>> no nul warning code. >>> >>> Most importantly it moves the SSA_NAME handling from >>> unterminated_array to string_constant, thereby fixing >>> another round of xfails in the strlen and stpcpy test cases. >>> >>> I need to say that the fix for bug 86622 is relying in >>> type info on the pointer which is probably not safe in >>> GIMPLE in the light of the recent discussion. >>> >>> I had to add two further exceptions, which should >>> be safe in general: that is a pointer arithmentic on a string >>> literal is okay, and arithmetic on a string constant >>> that is exactly the size of the whole DECL, cannot >>> access an adjacent member. >>> >>> >>> Bootstrapped and reg-tested on x86_64-pc-linux-gnu. >>> Is it OK for trunk? >>> >>> >>> Thanks >>> Bernd. >>> >>> >>> patch-cleanup-no-nul.diff >>> >>> gcc: >>> 2018-09-16 Bernd Edlinger <bernd.edlinger@hotmail.de> >>> >>> * builtins.h (unterminated_array): Remove prototype. >>> * builtins.c (unterminated_array): Simplify. Make static. >>> (expand_builtin_strcpy_args): Don't use TREE_NO_WARNING here. >>> (expand_builtin_stpcpy_1): Remove warn_string_no_nul without effect. >>> * expr.c (string_constant): Handle SSA_NAME. Add more exceptions >>> where pointer arithmetic is safe. >>> * gimple-fold.c (get_range_strlen): Handle nonstr like in c_strlen. >>> (get_max_strlen): Remove the unnecessary mynonstr handling. >>> (gimple_fold_builtin_strcpy): Simplify. >>> (gimple_fold_builtin_stpcpy): Simplify. >>> (gimple_fold_builtin_sprintf): Remove NO_WARNING propagation >>> without effect. >>> (gimple_fold_builtin_strlen): Simplify. >>> >>> testsuite: >>> 2018-09-16 Bernd Edlinger <bernd.edlinger@hotmail.de> >>> >>> * gcc.dg/warn-stpcpy-no-nul.c: Remove xfails. >>> * gcc.dg/warn-strlen-no-nul.c: Remove xfails. >>> >>> Index: gcc/builtins.c >>> =================================================================== >>> --- gcc/builtins.c (revision 264342) >>> +++ gcc/builtins.c (working copy) >>> @@ -567,31 +567,12 @@ warn_string_no_nul (location_t loc, const char *fn >>> the declaration of the object of which the array is a member or >>> element. Otherwise return null. */ >>> >>> -tree >>> +static tree >>> unterminated_array (tree exp) >>> { >>> - if (TREE_CODE (exp) == SSA_NAME) >>> - { >>> - gimple *stmt = SSA_NAME_DEF_STMT (exp); >>> - if (!is_gimple_assign (stmt)) >>> - return NULL_TREE; >>> - >>> - tree rhs1 = gimple_assign_rhs1 (stmt); >>> - tree_code code = gimple_assign_rhs_code (stmt); >>> - if (code == ADDR_EXPR >>> - && TREE_CODE (TREE_OPERAND (rhs1, 0)) == ARRAY_REF) >>> - rhs1 = rhs1; >>> - else if (code != POINTER_PLUS_EXPR) >>> - return NULL_TREE; >>> - >>> - exp = rhs1; >>> - } >>> - >>> tree nonstr = NULL; >>> - if (c_strlen (exp, 1, &nonstr, 1) == NULL && nonstr) >>> - return nonstr; >>> - >>> - return NULL_TREE; >>> + c_strlen (exp, 1, &nonstr); >>> + return nonstr; >>> } >> Sigh. This is going to conflict with patch #6 from Martin's kit. >> > > Sorry, it just feels wrong to do this folding here instead of in > string_constant. > > I think the handling of POINTER_PLUS_EXPR above, is faulty, > because it is ignoring the offset parameter, which typically > contains the offset part, may add an offset to a different > structure member or another array index. That is what happened > in PR 86622. > > So you are likely looking at the wrong index, or even the wrong > structure member. I'm not disagreeing that something's wrong here -- the whole concept that we extract the rhs and totally ignore the offset seems wrong. I've stumbled over it working through issues with either patch #4 or #6 from Martin. But I felt I needed to go back and reevaluate any assumptions I had about how the code was supposed to be used before I called it out. Your expr.c changes may be worth pushing through independently of the rest. AFAICT they're really just exposing more cases where we can determine that we're working with a stirng constant. > > >> >>> >>> /* Compute the length of a null-terminated character string or wide >>> @@ -3936,8 +3917,7 @@ expand_builtin_strcpy_args (tree exp, tree dest, t >>> if (tree nonstr = unterminated_array (src)) >>> { >>> /* NONSTR refers to the non-nul terminated constant array. */ >>> - if (!TREE_NO_WARNING (exp)) >>> - warn_string_no_nul (EXPR_LOCATION (exp), "strcpy", src, nonstr); >>> + warn_string_no_nul (EXPR_LOCATION (exp), "strcpy", src, nonstr); >>> return NULL_RTX; >>> } >> There's also some target dependencies to be concerned about. I'll have >> to dig out the thread, but in general removing these TREE_NO_WARNING >> checks is probably a bad idea -- you're likely introducing redundant >> warnings on one or more targets (but not x86). >> > > I just wondered why use if (!TREE_NO_WARNING(exp)) when warn_string_no_nul > uses if (!TREE_NO_WARNING(src)), and sets TREE_NO_WARNING(src) on success. We may be doing too much here in some cases, but the general idea is to avoid duplicated warnings on one or more targets. IIRC it depends on how they handle the various cases where you lower from one builtin to another at expansion time. Hence my comment that we'd need to go back and look at that discussion before ripping out so much nowarning stuff. It's there for a reason (though I'm not convinced we're using it consistently). > >> >> There may be things in there we want to take. But my focus is going to >> be on getting the #4 and #6 patches from Martin's kit resolved (while he >> works on the string length range stuff). >> > > Oh, you are aware that I have a proposed patch on the string length range > vs. gimple semantics here: > > https://gcc.gnu.org/ml/gcc-patches/2018-09/msg00805.html Yes, I'm aware of it. jeff
On 09/17/18 20:32, Jeff Law wrote: > On 9/17/18 12:20 PM, Bernd Edlinger wrote: >> On 09/17/18 19:33, Jeff Law wrote: >>> On 9/16/18 1:58 PM, Bernd Edlinger wrote: >>>> Hi, >>>> >>>> this is a cleanup of the recently added strlen/strcpy/stpcpy >>>> no nul warning code. >>>> >>>> Most importantly it moves the SSA_NAME handling from >>>> unterminated_array to string_constant, thereby fixing >>>> another round of xfails in the strlen and stpcpy test cases. >>>> >>>> I need to say that the fix for bug 86622 is relying in >>>> type info on the pointer which is probably not safe in >>>> GIMPLE in the light of the recent discussion. >>>> >>>> I had to add two further exceptions, which should >>>> be safe in general: that is a pointer arithmentic on a string >>>> literal is okay, and arithmetic on a string constant >>>> that is exactly the size of the whole DECL, cannot >>>> access an adjacent member. >>>> >>>> >>>> Bootstrapped and reg-tested on x86_64-pc-linux-gnu. >>>> Is it OK for trunk? >>>> >>>> >>>> Thanks >>>> Bernd. >>>> >>>> >>>> patch-cleanup-no-nul.diff >>>> >>>> gcc: >>>> 2018-09-16 Bernd Edlinger <bernd.edlinger@hotmail.de> >>>> >>>> * builtins.h (unterminated_array): Remove prototype. >>>> * builtins.c (unterminated_array): Simplify. Make static. >>>> (expand_builtin_strcpy_args): Don't use TREE_NO_WARNING here. >>>> (expand_builtin_stpcpy_1): Remove warn_string_no_nul without effect. >>>> * expr.c (string_constant): Handle SSA_NAME. Add more exceptions >>>> where pointer arithmetic is safe. >>>> * gimple-fold.c (get_range_strlen): Handle nonstr like in c_strlen. >>>> (get_max_strlen): Remove the unnecessary mynonstr handling. >>>> (gimple_fold_builtin_strcpy): Simplify. >>>> (gimple_fold_builtin_stpcpy): Simplify. >>>> (gimple_fold_builtin_sprintf): Remove NO_WARNING propagation >>>> without effect. >>>> (gimple_fold_builtin_strlen): Simplify. >>>> >>>> testsuite: >>>> 2018-09-16 Bernd Edlinger <bernd.edlinger@hotmail.de> >>>> >>>> * gcc.dg/warn-stpcpy-no-nul.c: Remove xfails. >>>> * gcc.dg/warn-strlen-no-nul.c: Remove xfails. >>>> >>>> Index: gcc/builtins.c >>>> =================================================================== >>>> --- gcc/builtins.c (revision 264342) >>>> +++ gcc/builtins.c (working copy) >>>> @@ -567,31 +567,12 @@ warn_string_no_nul (location_t loc, const char *fn >>>> the declaration of the object of which the array is a member or >>>> element. Otherwise return null. */ >>>> >>>> -tree >>>> +static tree >>>> unterminated_array (tree exp) >>>> { >>>> - if (TREE_CODE (exp) == SSA_NAME) >>>> - { >>>> - gimple *stmt = SSA_NAME_DEF_STMT (exp); >>>> - if (!is_gimple_assign (stmt)) >>>> - return NULL_TREE; >>>> - >>>> - tree rhs1 = gimple_assign_rhs1 (stmt); >>>> - tree_code code = gimple_assign_rhs_code (stmt); >>>> - if (code == ADDR_EXPR >>>> - && TREE_CODE (TREE_OPERAND (rhs1, 0)) == ARRAY_REF) >>>> - rhs1 = rhs1; >>>> - else if (code != POINTER_PLUS_EXPR) >>>> - return NULL_TREE; >>>> - >>>> - exp = rhs1; >>>> - } >>>> - >>>> tree nonstr = NULL; >>>> - if (c_strlen (exp, 1, &nonstr, 1) == NULL && nonstr) >>>> - return nonstr; >>>> - >>>> - return NULL_TREE; >>>> + c_strlen (exp, 1, &nonstr); >>>> + return nonstr; >>>> } >>> Sigh. This is going to conflict with patch #6 from Martin's kit. >>> >> >> Sorry, it just feels wrong to do this folding here instead of in >> string_constant. >> >> I think the handling of POINTER_PLUS_EXPR above, is faulty, >> because it is ignoring the offset parameter, which typically >> contains the offset part, may add an offset to a different >> structure member or another array index. That is what happened >> in PR 86622. >> >> So you are likely looking at the wrong index, or even the wrong >> structure member. > I'm not disagreeing that something's wrong here -- the whole concept > that we extract the rhs and totally ignore the offset seems wrong. I've > stumbled over it working through issues with either patch #4 or #6 from > Martin. But I felt I needed to go back and reevaluate any assumptions I > had about how the code was supposed to be used before I called it out. > > > Your expr.c changes may be worth pushing through independently of the > rest. AFAICT they're really just exposing more cases where we can > determine that we're working with a stirng constant. > I think that moves just the folding from here to expr.c, I don't see how the change in part #6 on unterminated_array is supposed to work, I quote it here and add some comments: > tree > -unterminated_array (tree exp) > +unterminated_array (tree exp, tree *size /* = NULL */, bool *exact /* = NULL */) > { > + /* Offset from the beginning of the array or null. */ > + tree off = NULL_TREE; > + > if (TREE_CODE (exp) == SSA_NAME) > { > gimple *stmt = SSA_NAME_DEF_STMT (exp); > @@ -595,18 +600,43 @@ unterminated_array (tree exp) > > tree rhs1 = gimple_assign_rhs1 (stmt); > tree_code code = gimple_assign_rhs_code (stmt); > - if (code == ADDR_EXPR > - && TREE_CODE (TREE_OPERAND (rhs1, 0)) == ARRAY_REF) > - rhs1 = rhs1; > - else if (code != POINTER_PLUS_EXPR) > + if ((code == ADDR_EXPR > + && TREE_CODE (TREE_OPERAND (rhs1, 0)) == ARRAY_REF) > + || code == POINTER_PLUS_EXPR) > + { > + /* Store the index or offset. */ > + off = gimple_assign_rhs2 (stmt); ADDR_EXPR does not have rhs2, right? > + exp = rhs1; > + } > + else > return NULL_TREE; > - > - exp = rhs1; > } > > tree nonstr; > - if (c_strlen (exp, 1, &nonstr) && nonstr) > - return nonstr; > + tree len = c_strlen (exp, 1, &nonstr); > + if (len && nonstr) > + { > + if (size) > + { > + if (off) > + { > + if (TREE_CODE (off) == INTEGER_CST) > + { > + /* Subtract the offset from the size of the array. */ > + *exact = true; > + off = fold_convert (ssizetype, off); > + len = fold_build2 (MINUS_EXPR, ssizetype, len, off); Underflow could happen here, off could even be negative. Something similar to the check in string_constant should be done to avoid that off might be moving the access to another array member: if (POINTER_TYPE_P (TREE_TYPE (rhs1)) && TREE_CODE (TREE_TYPE (TREE_TYPE (rhs1))) == ARRAY_TYPE && !(decl && !*decl) && !(decl && tree_fits_uhwi_p (DECL_SIZE_UNIT (*decl)) && mem_size && tree_fits_uhwi_p (*mem_size) && tree_int_cst_equal (*mem_size, DECL_SIZE_UNIT (*decl)))) > + } > + else > + *exact = false; > + } > + else > + *exact = true; > + > + *size = len; > + } > + return nonstr; > + } > > return NULL_TREE; > } Yeah, sorry, but this looks like a hack. I would just use c_strlen if I need the length and optionally nonstr. The previous version was a convenience when you are only interested in nonstr, which may happen. I suppose the expr.c change will likely work alone, but it was designed to replace the stuff here. So I will try to split the expr.c part out, and post it tomorrow. Bernd.
On 9/17/18 1:18 PM, Bernd Edlinger wrote: > > I suppose the expr.c change will likely work alone, but > it was designed to replace the stuff here. > > So I will try to split the expr.c part out, and post it > tomorrow. It does work alone. I've already verified that here :-) BUt will probably call it a night without pushing it to the trunk. jeff
On 9/17/18 1:18 PM, Bernd Edlinger wrote: > On 09/17/18 20:32, Jeff Law wrote: >> On 9/17/18 12:20 PM, Bernd Edlinger wrote: >>> On 09/17/18 19:33, Jeff Law wrote: >>>> On 9/16/18 1:58 PM, Bernd Edlinger wrote: >>>>> Hi, >>>>> >>>>> this is a cleanup of the recently added strlen/strcpy/stpcpy >>>>> no nul warning code. >>>>> >>>>> Most importantly it moves the SSA_NAME handling from >>>>> unterminated_array to string_constant, thereby fixing >>>>> another round of xfails in the strlen and stpcpy test cases. >>>>> >>>>> I need to say that the fix for bug 86622 is relying in >>>>> type info on the pointer which is probably not safe in >>>>> GIMPLE in the light of the recent discussion. >>>>> >>>>> I had to add two further exceptions, which should >>>>> be safe in general: that is a pointer arithmentic on a string >>>>> literal is okay, and arithmetic on a string constant >>>>> that is exactly the size of the whole DECL, cannot >>>>> access an adjacent member. >>>>> >>>>> >>>>> Bootstrapped and reg-tested on x86_64-pc-linux-gnu. >>>>> Is it OK for trunk? >>>>> >>>>> >>>>> Thanks >>>>> Bernd. >>>>> >>>>> >>>>> patch-cleanup-no-nul.diff >>>>> >>>>> gcc: >>>>> 2018-09-16 Bernd Edlinger <bernd.edlinger@hotmail.de> >>>>> >>>>> * builtins.h (unterminated_array): Remove prototype. >>>>> * builtins.c (unterminated_array): Simplify. Make static. >>>>> (expand_builtin_strcpy_args): Don't use TREE_NO_WARNING here. >>>>> (expand_builtin_stpcpy_1): Remove warn_string_no_nul without effect. >>>>> * expr.c (string_constant): Handle SSA_NAME. Add more exceptions >>>>> where pointer arithmetic is safe. >>>>> * gimple-fold.c (get_range_strlen): Handle nonstr like in c_strlen. >>>>> (get_max_strlen): Remove the unnecessary mynonstr handling. >>>>> (gimple_fold_builtin_strcpy): Simplify. >>>>> (gimple_fold_builtin_stpcpy): Simplify. >>>>> (gimple_fold_builtin_sprintf): Remove NO_WARNING propagation >>>>> without effect. >>>>> (gimple_fold_builtin_strlen): Simplify. >>>>> >>>>> testsuite: >>>>> 2018-09-16 Bernd Edlinger <bernd.edlinger@hotmail.de> >>>>> >>>>> * gcc.dg/warn-stpcpy-no-nul.c: Remove xfails. >>>>> * gcc.dg/warn-strlen-no-nul.c: Remove xfails. >>>>> >>>>> Index: gcc/builtins.c >>>>> =================================================================== >>>>> --- gcc/builtins.c (revision 264342) >>>>> +++ gcc/builtins.c (working copy) >>>>> @@ -567,31 +567,12 @@ warn_string_no_nul (location_t loc, const char *fn >>>>> the declaration of the object of which the array is a member or >>>>> element. Otherwise return null. */ >>>>> >>>>> -tree >>>>> +static tree >>>>> unterminated_array (tree exp) >>>>> { >>>>> - if (TREE_CODE (exp) == SSA_NAME) >>>>> - { >>>>> - gimple *stmt = SSA_NAME_DEF_STMT (exp); >>>>> - if (!is_gimple_assign (stmt)) >>>>> - return NULL_TREE; >>>>> - >>>>> - tree rhs1 = gimple_assign_rhs1 (stmt); >>>>> - tree_code code = gimple_assign_rhs_code (stmt); >>>>> - if (code == ADDR_EXPR >>>>> - && TREE_CODE (TREE_OPERAND (rhs1, 0)) == ARRAY_REF) >>>>> - rhs1 = rhs1; >>>>> - else if (code != POINTER_PLUS_EXPR) >>>>> - return NULL_TREE; >>>>> - >>>>> - exp = rhs1; >>>>> - } >>>>> - >>>>> tree nonstr = NULL; >>>>> - if (c_strlen (exp, 1, &nonstr, 1) == NULL && nonstr) >>>>> - return nonstr; >>>>> - >>>>> - return NULL_TREE; >>>>> + c_strlen (exp, 1, &nonstr); >>>>> + return nonstr; >>>>> } >>>> Sigh. This is going to conflict with patch #6 from Martin's kit. >>>> >>> >>> Sorry, it just feels wrong to do this folding here instead of in >>> string_constant. >>> >>> I think the handling of POINTER_PLUS_EXPR above, is faulty, >>> because it is ignoring the offset parameter, which typically >>> contains the offset part, may add an offset to a different >>> structure member or another array index. That is what happened >>> in PR 86622. >>> >>> So you are likely looking at the wrong index, or even the wrong >>> structure member. >> I'm not disagreeing that something's wrong here -- the whole concept >> that we extract the rhs and totally ignore the offset seems wrong. I've >> stumbled over it working through issues with either patch #4 or #6 from >> Martin. But I felt I needed to go back and reevaluate any assumptions I >> had about how the code was supposed to be used before I called it out. >> >> >> Your expr.c changes may be worth pushing through independently of the >> rest. AFAICT they're really just exposing more cases where we can >> determine that we're working with a stirng constant. >> > > I think that moves just the folding from here to expr.c, > I don't see how the change in part #6 on unterminated_array > is supposed to work, I quote it here and add some comments: > Essentially there's a couple of concepts he wants to get in unterminated_array. First, given an address, if there's a variable part we want to clear exact so we can adjust the text of the message in the caller. ie "exceeds the size" vs "may exceed the size". Second, he really wants LEN to be set to the length of the string for whatever the constant part of the address might be, even if it's potentially not properly terminated. So given: const char b[][5] = { /* { dg-message "declared here" } */ "12", "345", "6789", "abcde" }; A reference like: T (&b[3][1] + v0, bsz); We want the length of the string at &b[3][1] into *LEN. That's used to provide the potential length of the string in the message. I don't think we can get that from c_strlen right now. Right now we've defined c_strlen as (reasonably) returning NULL for the length when we've got an string without proper termination. I'm hesitant to provide a boolean argument that essentially says give me whatever length you've computed, even if the string isn't properly terminated. But conceptually that's one of the things we'd need. It's also needed for patch #4. Jeff ps. Yes there's still some issues in the code. I'm mostly trying to highlight how it's being used and what requirements we'd have if we were going to do something like you've suggested in your patch to unterminated_array.
On 09/18/18 07:31, Jeff Law wrote: > On 9/17/18 1:18 PM, Bernd Edlinger wrote: >> On 09/17/18 20:32, Jeff Law wrote: >>> On 9/17/18 12:20 PM, Bernd Edlinger wrote: >>>> On 09/17/18 19:33, Jeff Law wrote: >>>>> On 9/16/18 1:58 PM, Bernd Edlinger wrote: >>>>>> Hi, >>>>>> >>>>>> this is a cleanup of the recently added strlen/strcpy/stpcpy >>>>>> no nul warning code. >>>>>> >>>>>> Most importantly it moves the SSA_NAME handling from >>>>>> unterminated_array to string_constant, thereby fixing >>>>>> another round of xfails in the strlen and stpcpy test cases. >>>>>> >>>>>> I need to say that the fix for bug 86622 is relying in >>>>>> type info on the pointer which is probably not safe in >>>>>> GIMPLE in the light of the recent discussion. >>>>>> >>>>>> I had to add two further exceptions, which should >>>>>> be safe in general: that is a pointer arithmentic on a string >>>>>> literal is okay, and arithmetic on a string constant >>>>>> that is exactly the size of the whole DECL, cannot >>>>>> access an adjacent member. >>>>>> >>>>>> >>>>>> Bootstrapped and reg-tested on x86_64-pc-linux-gnu. >>>>>> Is it OK for trunk? >>>>>> >>>>>> >>>>>> Thanks >>>>>> Bernd. >>>>>> >>>>>> >>>>>> patch-cleanup-no-nul.diff >>>>>> >>>>>> gcc: >>>>>> 2018-09-16 Bernd Edlinger <bernd.edlinger@hotmail.de> >>>>>> >>>>>> * builtins.h (unterminated_array): Remove prototype. >>>>>> * builtins.c (unterminated_array): Simplify. Make static. >>>>>> (expand_builtin_strcpy_args): Don't use TREE_NO_WARNING here. >>>>>> (expand_builtin_stpcpy_1): Remove warn_string_no_nul without effect. >>>>>> * expr.c (string_constant): Handle SSA_NAME. Add more exceptions >>>>>> where pointer arithmetic is safe. >>>>>> * gimple-fold.c (get_range_strlen): Handle nonstr like in c_strlen. >>>>>> (get_max_strlen): Remove the unnecessary mynonstr handling. >>>>>> (gimple_fold_builtin_strcpy): Simplify. >>>>>> (gimple_fold_builtin_stpcpy): Simplify. >>>>>> (gimple_fold_builtin_sprintf): Remove NO_WARNING propagation >>>>>> without effect. >>>>>> (gimple_fold_builtin_strlen): Simplify. >>>>>> >>>>>> testsuite: >>>>>> 2018-09-16 Bernd Edlinger <bernd.edlinger@hotmail.de> >>>>>> >>>>>> * gcc.dg/warn-stpcpy-no-nul.c: Remove xfails. >>>>>> * gcc.dg/warn-strlen-no-nul.c: Remove xfails. >>>>>> >>>>>> Index: gcc/builtins.c >>>>>> =================================================================== >>>>>> --- gcc/builtins.c (revision 264342) >>>>>> +++ gcc/builtins.c (working copy) >>>>>> @@ -567,31 +567,12 @@ warn_string_no_nul (location_t loc, const char *fn >>>>>> the declaration of the object of which the array is a member or >>>>>> element. Otherwise return null. */ >>>>>> >>>>>> -tree >>>>>> +static tree >>>>>> unterminated_array (tree exp) >>>>>> { >>>>>> - if (TREE_CODE (exp) == SSA_NAME) >>>>>> - { >>>>>> - gimple *stmt = SSA_NAME_DEF_STMT (exp); >>>>>> - if (!is_gimple_assign (stmt)) >>>>>> - return NULL_TREE; >>>>>> - >>>>>> - tree rhs1 = gimple_assign_rhs1 (stmt); >>>>>> - tree_code code = gimple_assign_rhs_code (stmt); >>>>>> - if (code == ADDR_EXPR >>>>>> - && TREE_CODE (TREE_OPERAND (rhs1, 0)) == ARRAY_REF) >>>>>> - rhs1 = rhs1; >>>>>> - else if (code != POINTER_PLUS_EXPR) >>>>>> - return NULL_TREE; >>>>>> - >>>>>> - exp = rhs1; >>>>>> - } >>>>>> - >>>>>> tree nonstr = NULL; >>>>>> - if (c_strlen (exp, 1, &nonstr, 1) == NULL && nonstr) >>>>>> - return nonstr; >>>>>> - >>>>>> - return NULL_TREE; >>>>>> + c_strlen (exp, 1, &nonstr); >>>>>> + return nonstr; >>>>>> } >>>>> Sigh. This is going to conflict with patch #6 from Martin's kit. >>>>> >>>> >>>> Sorry, it just feels wrong to do this folding here instead of in >>>> string_constant. >>>> >>>> I think the handling of POINTER_PLUS_EXPR above, is faulty, >>>> because it is ignoring the offset parameter, which typically >>>> contains the offset part, may add an offset to a different >>>> structure member or another array index. That is what happened >>>> in PR 86622. >>>> >>>> So you are likely looking at the wrong index, or even the wrong >>>> structure member. >>> I'm not disagreeing that something's wrong here -- the whole concept >>> that we extract the rhs and totally ignore the offset seems wrong. I've >>> stumbled over it working through issues with either patch #4 or #6 from >>> Martin. But I felt I needed to go back and reevaluate any assumptions I >>> had about how the code was supposed to be used before I called it out. >>> >>> >>> Your expr.c changes may be worth pushing through independently of the >>> rest. AFAICT they're really just exposing more cases where we can >>> determine that we're working with a stirng constant. >>> >> >> I think that moves just the folding from here to expr.c, >> I don't see how the change in part #6 on unterminated_array >> is supposed to work, I quote it here and add some comments: >> > Essentially there's a couple of concepts he wants to get in > unterminated_array. > > First, given an address, if there's a variable part we want to clear > exact so we can adjust the text of the message in the caller. ie > "exceeds the size" vs "may exceed the size". > > Second, he really wants LEN to be set to the length of the string for > whatever the constant part of the address might be, even if it's > potentially not properly terminated. > > So given: > > const char b[][5] = { /* { dg-message "declared here" } */ > "12", "345", "6789", "abcde" > }; > > A reference like: > > T (&b[3][1] + v0, bsz); > > We want the length of the string at &b[3][1] into *LEN. That's used to > provide the potential length of the string in the message. > > I don't think we can get that from c_strlen right now. Right now we've > defined c_strlen as (reasonably) returning NULL for the length when > we've got an string without proper termination. > > I'm hesitant to provide a boolean argument that essentially says give me > whatever length you've computed, even if the string isn't properly > terminated. But conceptually that's one of the things we'd need. It's > also needed for patch #4. > > Jeff > > ps. Yes there's still some issues in the code. I'm mostly trying to > highlight how it's being used and what requirements we'd have if we were > going to do something like you've suggested in your patch to > unterminated_array. > Hmm, you know, I wrote a while ago the following: https://gcc.gnu.org/ml/gcc-patches/2018-09/msg00411.html Where I suggested to change c_strlen parameter nonstr to a structure, where additional information could go. There are a lot more informations that could be relevant for warnings. So it would be easy to convey the unterminated string length there, also I could imagine to diagnose unaligned wide string constants, if we have a decl with a too low alignment factor, or a known unaligned offset for instance. Also the location of the expression on which c_strlen found the unterminated string, could be of interest, especially when get_range_strlen follows phi nodes. Well, I have the impression that the 6/6 patch should be split up in a part that uses c_strlen in its current form, and a follow-up patch that adds any additional info. I prefer doing things step-by-step, you know. Note that the example given is probably unsafe: > T (&b[3][1] + v0, bsz); This does not pass the check in string_constant because it looks like _2 = (char*)&b + _1; _3 = strlen (_2); I have no way to prove that v0 is not larger than sizeof (b[3]). However T(&a[1] + v0, bsz) will definitely work. So the warning will likely get completely bogus data out of unterminated_array. By the way test test case for pr87053 is an example of a false positive warning (it comes twice even though TREE_NO_WARNING is used). gcc pr87053.c pr87053.c: In function 'main': pr87053.c:15:26: warning: 'strlen' argument missing terminating nul [-Wstringop-overflow=] 15 | if (__builtin_strlen (u.z) != 7) | ~^~ pr87053.c:11:3: note: referenced argument declared here 11 | } u = {{"1234", "567"}}; | ^ pr87053.c:15:26: warning: 'strlen' argument missing terminating nul [-Wstringop-overflow=] 15 | if (__builtin_strlen (u.z) != 7) | ~^~ pr87053.c:11:3: note: referenced argument declared here 11 | } u = {{"1234", "567"}}; | ^ I think the duplicate warnings will not go away unless this warning is only diagnosed in the tree-ssa-strlen pass instead of the folding code, which happens repeatedly. Bernd.
On 9/18/18 5:44 AM, Bernd Edlinger wrote: >> > > Hmm, you know, I wrote a while ago the following: > https://gcc.gnu.org/ml/gcc-patches/2018-09/msg00411.html > > Where I suggested to change c_strlen parameter nonstr to a > structure, where additional information could go. It certainly seems better than continually adding more parameters and/or having a given parameter have multiple overloaded meanings. We'd fill in everything we can and let the caller determine what bits they need. Martin has suggested something similar. > > Well, I have the impression that the 6/6 patch should be split > up in a part that uses c_strlen in its current form, and a > follow-up patch that adds any additional info. > I prefer doing things step-by-step, you know. I'm pretty sure it's not going to be able to use c_strlen in its current form. There are times when it really wants the length of the string, even if it's not terminated. > > Note that the example given is probably unsafe: >> T (&b[3][1] + v0, bsz); > > This does not pass the check in string_constant because it > looks like _2 = (char*)&b + _1; _3 = strlen (_2); > I have no way to prove that v0 is not larger than sizeof (b[3]). That's OK. The existence of the variable part turns "must" warnings into "may" warnings precisely because we don't know how v0 impacts things. > > By the way test test case for pr87053 is an example > of a false positive warning (it comes twice even though > TREE_NO_WARNING is used). > > gcc pr87053.c > pr87053.c: In function 'main': > pr87053.c:15:26: warning: 'strlen' argument missing terminating nul [-Wstringop-overflow=] > 15 | if (__builtin_strlen (u.z) != 7) > | ~^~ > pr87053.c:11:3: note: referenced argument declared here > 11 | } u = {{"1234", "567"}}; > | ^ > pr87053.c:15:26: warning: 'strlen' argument missing terminating nul [-Wstringop-overflow=] > 15 | if (__builtin_strlen (u.z) != 7) > | ~^~ > pr87053.c:11:3: note: referenced argument declared here > 11 | } u = {{"1234", "567"}}; > | ^ > > I think the duplicate warnings will not go away unless > this warning is only diagnosed in the tree-ssa-strlen > pass instead of the folding code, which happens repeatedly. Please file a bug. FWIW, I wouldn't necessarily rely on on the strlen pass not being repeated either. jeff
Hi Jeff.
I noticed that your commit r264328 introduced this:
gcc/builtins.c:
...
579 tree rhs1 = gimple_assign_rhs1 (stmt);
580 tree_code code = gimple_assign_rhs_code (stmt);
581 if (code == ADDR_EXPR
582 && TREE_CODE (TREE_OPERAND (rhs1, 0)) == ARRAY_REF)
583 rhs1 = rhs1; <---- here
584 else if (code != POINTER_PLUS_EXPR)
585 return NULL_TREE;
...
which is reported by LLVM as warning:
gcc/builtins.c:583:2:Semantic Issue: explicitly assigning value of variable of type 'tree' (aka 'tree_node *') to itself: -Wself-assign
Can you please fix that?
Thanks,
Martin
On 9/22/18 8:32 PM, Martin Liška wrote: > Hi Jeff. > > I noticed that your commit r264328 introduced this: > > gcc/builtins.c: > ... > 579 tree rhs1 = gimple_assign_rhs1 (stmt); > 580 tree_code code = gimple_assign_rhs_code (stmt); > 581 if (code == ADDR_EXPR > 582 && TREE_CODE (TREE_OPERAND (rhs1, 0)) == ARRAY_REF) > 583 rhs1 = rhs1; <---- here > 584 else if (code != POINTER_PLUS_EXPR) > 585 return NULL_TREE; > ... > > which is reported by LLVM as warning: > gcc/builtins.c:583:2:Semantic Issue: explicitly assigning value of variable of type 'tree' (aka 'tree_node *') to itself: -Wself-assign > > Can you please fix that? > Thanks, > Martin Apparently the same was already reported here: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87387 Martin
On 9/22/18 12:32 PM, Martin Liška wrote: > Hi Jeff. > > I noticed that your commit r264328 introduced this: > > gcc/builtins.c: > ... > 579 tree rhs1 = gimple_assign_rhs1 (stmt); > 580 tree_code code = gimple_assign_rhs_code (stmt); > 581 if (code == ADDR_EXPR > 582 && TREE_CODE (TREE_OPERAND (rhs1, 0)) == ARRAY_REF) > 583 rhs1 = rhs1; <---- here > 584 else if (code != POINTER_PLUS_EXPR) > 585 return NULL_TREE; > ... > > which is reported by LLVM as warning: > gcc/builtins.c:583:2:Semantic Issue: explicitly assigning value of > variable of type 'tree' (aka 'tree_node *') to itself: -Wself-assign > > Can you please fix that? Yes. I'll be addressed with the changes I'm going to install from Bernd/Martin. jeff
On 9/16/18 1:58 PM, Bernd Edlinger wrote: > Hi, > > this is a cleanup of the recently added strlen/strcpy/stpcpy > no nul warning code. > > Most importantly it moves the SSA_NAME handling from > unterminated_array to string_constant, thereby fixing > another round of xfails in the strlen and stpcpy test cases. > > I need to say that the fix for bug 86622 is relying in > type info on the pointer which is probably not safe in > GIMPLE in the light of the recent discussion. > > I had to add two further exceptions, which should > be safe in general: that is a pointer arithmentic on a string > literal is okay, and arithmetic on a string constant > that is exactly the size of the whole DECL, cannot > access an adjacent member. > > > Bootstrapped and reg-tested on x86_64-pc-linux-gnu. > Is it OK for trunk? > > > Thanks > Bernd. > > > patch-cleanup-no-nul.diff > > gcc: > 2018-09-16 Bernd Edlinger <bernd.edlinger@hotmail.de> > > * builtins.h (unterminated_array): Remove prototype. > * builtins.c (unterminated_array): Simplify. Make static. > (expand_builtin_strcpy_args): Don't use TREE_NO_WARNING here. > (expand_builtin_stpcpy_1): Remove warn_string_no_nul without effect. > * expr.c (string_constant): Handle SSA_NAME. Add more exceptions > where pointer arithmetic is safe. > * gimple-fold.c (get_range_strlen): Handle nonstr like in c_strlen. > (get_max_strlen): Remove the unnecessary mynonstr handling. > (gimple_fold_builtin_strcpy): Simplify. > (gimple_fold_builtin_stpcpy): Simplify. > (gimple_fold_builtin_sprintf): Remove NO_WARNING propagation > without effect. > (gimple_fold_builtin_strlen): Simplify. So my thinking right now is to go forward with the API change to allow c_strlen to fill in a structure with relevant tidbits about the string. That in turn allows us to use simplify unterminated_array in a manner similar to what you've done in your patch -- while carrying forward the capabilities we need for Martin's nul terminator warnings. This would be combined with the expr.c chunks from your patch. However, most of the changes to drop NO_WARNING stuff should be handled separately. I don't think they're safe as-is. I'm also pretty sure the stpcpy changes in builtins.c aren't correct as-is. Jeff
On 09/24/18 19:48, Jeff Law wrote: > On 9/16/18 1:58 PM, Bernd Edlinger wrote: >> Hi, >> >> this is a cleanup of the recently added strlen/strcpy/stpcpy >> no nul warning code. >> >> Most importantly it moves the SSA_NAME handling from >> unterminated_array to string_constant, thereby fixing >> another round of xfails in the strlen and stpcpy test cases. >> >> I need to say that the fix for bug 86622 is relying in >> type info on the pointer which is probably not safe in >> GIMPLE in the light of the recent discussion. >> >> I had to add two further exceptions, which should >> be safe in general: that is a pointer arithmentic on a string >> literal is okay, and arithmetic on a string constant >> that is exactly the size of the whole DECL, cannot >> access an adjacent member. >> >> >> Bootstrapped and reg-tested on x86_64-pc-linux-gnu. >> Is it OK for trunk? >> >> >> Thanks >> Bernd. >> >> >> patch-cleanup-no-nul.diff >> >> gcc: >> 2018-09-16 Bernd Edlinger <bernd.edlinger@hotmail.de> >> >> * builtins.h (unterminated_array): Remove prototype. >> * builtins.c (unterminated_array): Simplify. Make static. >> (expand_builtin_strcpy_args): Don't use TREE_NO_WARNING here. >> (expand_builtin_stpcpy_1): Remove warn_string_no_nul without effect. >> * expr.c (string_constant): Handle SSA_NAME. Add more exceptions >> where pointer arithmetic is safe. >> * gimple-fold.c (get_range_strlen): Handle nonstr like in c_strlen. >> (get_max_strlen): Remove the unnecessary mynonstr handling. >> (gimple_fold_builtin_strcpy): Simplify. >> (gimple_fold_builtin_stpcpy): Simplify. >> (gimple_fold_builtin_sprintf): Remove NO_WARNING propagation >> without effect. >> (gimple_fold_builtin_strlen): Simplify. > So my thinking right now is to go forward with the API change to allow > c_strlen to fill in a structure with relevant tidbits about the string. > > That in turn allows us to use simplify unterminated_array in a manner > similar to what you've done in your patch -- while carrying forward the > capabilities we need for Martin's nul terminator warnings. This would > be combined with the expr.c chunks from your patch. > Do you want me to elaborate that idea? > However, most of the changes to drop NO_WARNING stuff should be handled > separately. I don't think they're safe as-is. I'm also pretty sure the > stpcpy changes in builtins.c aren't correct as-is. > > Well, I think you must be referring to this: @@ -3984,14 +3964,10 @@ expand_builtin_stpcpy_1 (tree exp, rtx target, mac compile-time, not an expression containing a string. This is because the latter will potentially produce pessimized code when used to produce the return value. */ - tree nonstr = NULL_TREE; if (!c_getstr (src, NULL) - || !(len = c_strlen (src, 0, &nonstr, 1))) + || !(len = c_strlen (src, 0))) return expand_movstr (dst, src, target, /*endp=*/2); - if (nonstr && !TREE_NO_WARNING (exp)) - warn_string_no_nul (EXPR_LOCATION (exp), "stpcpy", src, nonstr); - lenp1 = size_binop_loc (loc, PLUS_EXPR, len, ssize_int (1)); ret = expand_builtin_mempcpy_args (dst, src, lenp1, target, exp, /*endp=*/2); My observation is: If that one is necessary and does not only emit some duplicated warnings, then the test case must be incomplete, at least it did not regress when this code is removed. It is possible that there are cases where this expansion produces a warning where previous folding steps did not catch the issue, however they are probably rare, and come at a cost, which means duplicated warnings. Maybe there could a better way than TREE_NO_WARNING to get rid of the duplicated warnings. Maybe it will be best to concentrate the warnings on a single pass, which means expand will it not be, right? Bernd.
On 9/24/18 12:18 PM, Bernd Edlinger wrote: > On 09/24/18 19:48, Jeff Law wrote: >> On 9/16/18 1:58 PM, Bernd Edlinger wrote: >>> Hi, >>> >>> this is a cleanup of the recently added strlen/strcpy/stpcpy >>> no nul warning code. >>> >>> Most importantly it moves the SSA_NAME handling from >>> unterminated_array to string_constant, thereby fixing >>> another round of xfails in the strlen and stpcpy test cases. >>> >>> I need to say that the fix for bug 86622 is relying in >>> type info on the pointer which is probably not safe in >>> GIMPLE in the light of the recent discussion. >>> >>> I had to add two further exceptions, which should >>> be safe in general: that is a pointer arithmentic on a string >>> literal is okay, and arithmetic on a string constant >>> that is exactly the size of the whole DECL, cannot >>> access an adjacent member. >>> >>> >>> Bootstrapped and reg-tested on x86_64-pc-linux-gnu. >>> Is it OK for trunk? >>> >>> >>> Thanks >>> Bernd. >>> >>> >>> patch-cleanup-no-nul.diff >>> >>> gcc: >>> 2018-09-16 Bernd Edlinger <bernd.edlinger@hotmail.de> >>> >>> * builtins.h (unterminated_array): Remove prototype. >>> * builtins.c (unterminated_array): Simplify. Make static. >>> (expand_builtin_strcpy_args): Don't use TREE_NO_WARNING here. >>> (expand_builtin_stpcpy_1): Remove warn_string_no_nul without effect. >>> * expr.c (string_constant): Handle SSA_NAME. Add more exceptions >>> where pointer arithmetic is safe. >>> * gimple-fold.c (get_range_strlen): Handle nonstr like in c_strlen. >>> (get_max_strlen): Remove the unnecessary mynonstr handling. >>> (gimple_fold_builtin_strcpy): Simplify. >>> (gimple_fold_builtin_stpcpy): Simplify. >>> (gimple_fold_builtin_sprintf): Remove NO_WARNING propagation >>> without effect. >>> (gimple_fold_builtin_strlen): Simplify. >> So my thinking right now is to go forward with the API change to allow >> c_strlen to fill in a structure with relevant tidbits about the string. >> >> That in turn allows us to use simplify unterminated_array in a manner >> similar to what you've done in your patch -- while carrying forward the >> capabilities we need for Martin's nul terminator warnings. This would >> be combined with the expr.c chunks from your patch. >> > > Do you want me to elaborate that idea? No need. I've already got those bits here. > >> However, most of the changes to drop NO_WARNING stuff should be handled >> separately. I don't think they're safe as-is. I'm also pretty sure the >> stpcpy changes in builtins.c aren't correct as-is. >> >> > > Well, I think you must be referring to this: > > @@ -3984,14 +3964,10 @@ expand_builtin_stpcpy_1 (tree exp, rtx target, mac > compile-time, not an expression containing a string. This is > because the latter will potentially produce pessimized code > when used to produce the return value. */ > - tree nonstr = NULL_TREE; > if (!c_getstr (src, NULL) > - || !(len = c_strlen (src, 0, &nonstr, 1))) > + || !(len = c_strlen (src, 0))) > return expand_movstr (dst, src, target, /*endp=*/2); > > - if (nonstr && !TREE_NO_WARNING (exp)) > - warn_string_no_nul (EXPR_LOCATION (exp), "stpcpy", src, nonstr); > - > lenp1 = size_binop_loc (loc, PLUS_EXPR, len, ssize_int (1)); > ret = expand_builtin_mempcpy_args (dst, src, lenp1, > target, exp, /*endp=*/2); > > > My observation is: If that one is necessary and does not only emit some > duplicated warnings, then the test case must be incomplete, at least it did not > regress when this code is removed. I'm pretty sure the test is incomplete. > > Maybe there could a better way than TREE_NO_WARNING to get rid > of the duplicated warnings. > > Maybe it will be best to concentrate the warnings on a single pass, > which means expand will it not be, right? COnceptually getting all the warnings out of the folder is a good start, but insufficient. You'd need to look at the thread for the duplicated warnings due to how the expanders call into each other. jeff
On 9/16/18 1:58 PM, Bernd Edlinger wrote: > Hi, > > this is a cleanup of the recently added strlen/strcpy/stpcpy > no nul warning code. > > Most importantly it moves the SSA_NAME handling from > unterminated_array to string_constant, thereby fixing > another round of xfails in the strlen and stpcpy test cases. > > I need to say that the fix for bug 86622 is relying in > type info on the pointer which is probably not safe in > GIMPLE in the light of the recent discussion. > > I had to add two further exceptions, which should > be safe in general: that is a pointer arithmentic on a string > literal is okay, and arithmetic on a string constant > that is exactly the size of the whole DECL, cannot > access an adjacent member. > > > Bootstrapped and reg-tested on x86_64-pc-linux-gnu. > Is it OK for trunk? > > > Thanks > Bernd. > > > patch-cleanup-no-nul.diff > > gcc: > 2018-09-16 Bernd Edlinger <bernd.edlinger@hotmail.de> > > * builtins.h (unterminated_array): Remove prototype. > * builtins.c (unterminated_array): Simplify. Make static. > (expand_builtin_strcpy_args): Don't use TREE_NO_WARNING here. > (expand_builtin_stpcpy_1): Remove warn_string_no_nul without effect. > * expr.c (string_constant): Handle SSA_NAME. Add more exceptions > where pointer arithmetic is safe. > * gimple-fold.c (get_range_strlen): Handle nonstr like in c_strlen. > (get_max_strlen): Remove the unnecessary mynonstr handling. > (gimple_fold_builtin_strcpy): Simplify. > (gimple_fold_builtin_stpcpy): Simplify. > (gimple_fold_builtin_sprintf): Remove NO_WARNING propagation > without effect. > (gimple_fold_builtin_strlen): Simplify. > > testsuite: > 2018-09-16 Bernd Edlinger <bernd.edlinger@hotmail.de> > > * gcc.dg/warn-stpcpy-no-nul.c: Remove xfails. > * gcc.dg/warn-strlen-no-nul.c: Remove xfails. I extracted the unterminated_array simplifications and the changes to string_constant and committed them to the trunk. I left unterminated_array with external scope as a patch from Martin wants to call it from outside builtins.c. jeff commit c1451dd20f9064084df7b45c4635c1bcb57a712d Author: Jeff Law <law@torsion.usersys.redhat.com> Date: Mon Sep 17 14:09:55 2018 -0400 PR c/87387 * builtins.c (unterminated_array): Simplify. * expr.c (string_constant): Handle SSA_NAME. Add more exceptions where pointer arithmetic is safe. * gcc.dg/warn-stpcpy-no-nul.c: Drop unnecessary xfails. * gcc.dg/warn-stplen-no-nul.c: Likewise. diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 6be143e9f18..8ff607e4d23 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,10 @@ +2018-09-25 Bernd Edlinger <bernd.edlinger@hotmail.de> + + PR c/87387 + * builtins.c (unterminated_array): Simplify. + * expr.c (string_constant): Handle SSA_NAME. Add more exceptions + where pointer arithmetic is safe. + 2018-09-25 Richard Biener <rguenther@suse.de> PR debug/83941 diff --git a/gcc/builtins.c b/gcc/builtins.c index 1d4de099726..5f00208ff09 100644 --- a/gcc/builtins.c +++ b/gcc/builtins.c @@ -570,28 +570,9 @@ warn_string_no_nul (location_t loc, const char *fn, tree arg, tree decl) tree unterminated_array (tree exp) { - if (TREE_CODE (exp) == SSA_NAME) - { - gimple *stmt = SSA_NAME_DEF_STMT (exp); - if (!is_gimple_assign (stmt)) - return NULL_TREE; - - tree rhs1 = gimple_assign_rhs1 (stmt); - tree_code code = gimple_assign_rhs_code (stmt); - if (code == ADDR_EXPR - && TREE_CODE (TREE_OPERAND (rhs1, 0)) == ARRAY_REF) - rhs1 = rhs1; - else if (code != POINTER_PLUS_EXPR) - return NULL_TREE; - - exp = rhs1; - } - tree nonstr = NULL; - if (c_strlen (exp, 1, &nonstr, 1) == NULL && nonstr) - return nonstr; - - return NULL_TREE; + c_strlen (exp, 1, &nonstr); + return nonstr; } /* Compute the length of a null-terminated character string or wide diff --git a/gcc/expr.c b/gcc/expr.c index b8782b9b133..583c7f008ff 100644 --- a/gcc/expr.c +++ b/gcc/expr.c @@ -11372,7 +11372,10 @@ string_constant (tree arg, tree *ptr_offset, tree *mem_size, tree *decl) /* Avoid pointers to arrays (see bug 86622). */ if (POINTER_TYPE_P (TREE_TYPE (arg)) && TREE_CODE (TREE_TYPE (TREE_TYPE (arg))) == ARRAY_TYPE - && TREE_CODE (TREE_OPERAND (arg0, 0)) == ARRAY_REF) + && !(decl && !*decl) + && !(decl && tree_fits_uhwi_p (DECL_SIZE_UNIT (*decl)) + && mem_size && tree_fits_uhwi_p (*mem_size) + && tree_int_cst_equal (*mem_size, DECL_SIZE_UNIT (*decl)))) return NULL_TREE; tree type = TREE_TYPE (arg1); @@ -11381,6 +11384,38 @@ string_constant (tree arg, tree *ptr_offset, tree *mem_size, tree *decl) } return NULL_TREE; } + else if (TREE_CODE (arg) == SSA_NAME) + { + gimple *stmt = SSA_NAME_DEF_STMT (arg); + if (!is_gimple_assign (stmt)) + return NULL_TREE; + + tree rhs1 = gimple_assign_rhs1 (stmt); + tree_code code = gimple_assign_rhs_code (stmt); + if (code == ADDR_EXPR) + return string_constant (rhs1, ptr_offset, mem_size, decl); + else if (code != POINTER_PLUS_EXPR) + return NULL_TREE; + + tree offset; + if (tree str = string_constant (rhs1, &offset, mem_size, decl)) + { + /* Avoid pointers to arrays (see bug 86622). */ + if (POINTER_TYPE_P (TREE_TYPE (rhs1)) + && TREE_CODE (TREE_TYPE (TREE_TYPE (rhs1))) == ARRAY_TYPE + && !(decl && !*decl) + && !(decl && tree_fits_uhwi_p (DECL_SIZE_UNIT (*decl)) + && mem_size && tree_fits_uhwi_p (*mem_size) + && tree_int_cst_equal (*mem_size, DECL_SIZE_UNIT (*decl)))) + return NULL_TREE; + + tree rhs2 = gimple_assign_rhs2 (stmt); + tree type = TREE_TYPE (rhs2); + *ptr_offset = fold_build2 (PLUS_EXPR, type, offset, rhs2); + return str; + } + return NULL_TREE; + } else if (DECL_P (arg)) array = arg; else diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index 05dbb0d40ea..7b26b894b15 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,3 +1,8 @@ +2018-09-25 Jeff Law <law@redhat.com> + + * gcc.dg/warn-stpcpy-no-nul.c: Drop unnecessary xfails. + * gcc.dg/warn-stplen-no-nul.c: Likewise. + 2018-09-25 Alexandre Oliva <oliva@adacore.com> * gnat.dg/dinst.adb: Adjust for locviews. diff --git a/gcc/testsuite/gcc.dg/warn-stpcpy-no-nul.c b/gcc/testsuite/gcc.dg/warn-stpcpy-no-nul.c index 78c4a7f9286..e718010ec2a 100644 --- a/gcc/testsuite/gcc.dg/warn-stpcpy-no-nul.c +++ b/gcc/testsuite/gcc.dg/warn-stpcpy-no-nul.c @@ -71,13 +71,13 @@ void test_two_dim_array (char *d) T (&b[3][1] + 1); /* { dg-warning "nul" } */ T (&b[3][v0]); /* { dg-warning "nul" } */ T (&b[3][1] + v0); /* { dg-warning "nul" } */ - T (&b[3][v0] + v1); /* { dg-warning "nul" "bug ???" { xfail *-*-* } } */ + T (&b[3][v0] + v1); /* { dg-warning "nul" } */ T (&b[i3][i1]); /* { dg-warning "nul" } */ T (&b[i3][i1] + i1); /* { dg-warning "nul" } */ T (&b[i3][v0]); /* { dg-warning "nul" } */ T (&b[i3][i1] + v0); /* { dg-warning "nul" } */ - T (&b[i3][v0] + v1); /* { dg-warning "nul" "bug ???" { xfail *-*-* } } */ + T (&b[i3][v0] + v1); /* { dg-warning "nul" } */ T (v0 ? "" : b[0]); T (v0 ? "" : b[1]); diff --git a/gcc/testsuite/gcc.dg/warn-strlen-no-nul.c b/gcc/testsuite/gcc.dg/warn-strlen-no-nul.c index 997dfc3540f..b716aa44770 100644 --- a/gcc/testsuite/gcc.dg/warn-strlen-no-nul.c +++ b/gcc/testsuite/gcc.dg/warn-strlen-no-nul.c @@ -71,9 +71,9 @@ T (&b[3][v0] + v1); /* { dg-warning "nul" } */ T (&b[i3][i1]); /* { dg-warning "nul" } */ T (&b[i3][i1] + 1); /* { dg-warning "nul" } */ T (&b[i3][i1] + i1); /* { dg-warning "nul" } */ -T (&b[i3][v0]); /* { dg-warning "nul" "pr86919" { xfail *-*-* } } */ -T (&b[i3][i1] + v0); /* { dg-warning "nul" "pr86919" { xfail *-*-* } } */ -T (&b[i3][v0] + v1); /* { dg-warning "nul" "pr86919" { xfail *-*-* } } */ +T (&b[i3][v0]); /* { dg-warning "nul" } */ +T (&b[i3][i1] + v0); /* { dg-warning "nul" } */ +T (&b[i3][v0] + v1); /* { dg-warning "nul" } */ T (v0 ? "" : b[0]); T (v0 ? "" : b[1]); @@ -152,10 +152,10 @@ T (&s.b[1] + v0); /* { dg-warning "nul" } */ T (&s.b[i0]); /* { dg-warning "nul" } */ T (&s.b[i0] + i1); /* { dg-warning "nul" } */ -T (&s.b[i0] + v0); /* { dg-warning "nul" "pr86919" { xfail *-*-* } } */ +T (&s.b[i0] + v0); /* { dg-warning "nul" } */ T (&s.b[i1]); /* { dg-warning "nul" } */ T (&s.b[i1] + i1); /* { dg-warning "nul" } */ -T (&s.b[i1] + v0); /* { dg-warning "nul" "pr86919" { xfail *-*-* } } */ +T (&s.b[i1] + v0); /* { dg-warning "nul" } */ struct B { struct A a[2]; };
gcc:
2018-09-16 Bernd Edlinger <bernd.edlinger@hotmail.de>
* builtins.h (unterminated_array): Remove prototype.
* builtins.c (unterminated_array): Simplify. Make static.
(expand_builtin_strcpy_args): Don't use TREE_NO_WARNING here.
(expand_builtin_stpcpy_1): Remove warn_string_no_nul without effect.
* expr.c (string_constant): Handle SSA_NAME. Add more exceptions
where pointer arithmetic is safe.
* gimple-fold.c (get_range_strlen): Handle nonstr like in c_strlen.
(get_max_strlen): Remove the unnecessary mynonstr handling.
(gimple_fold_builtin_strcpy): Simplify.
(gimple_fold_builtin_stpcpy): Simplify.
(gimple_fold_builtin_sprintf): Remove NO_WARNING propagation
without effect.
(gimple_fold_builtin_strlen): Simplify.
testsuite:
2018-09-16 Bernd Edlinger <bernd.edlinger@hotmail.de>
* gcc.dg/warn-stpcpy-no-nul.c: Remove xfails.
* gcc.dg/warn-strlen-no-nul.c: Remove xfails.
Index: gcc/builtins.c
===================================================================
--- gcc/builtins.c (revision 264342)
+++ gcc/builtins.c (working copy)
@@ -567,31 +567,12 @@ warn_string_no_nul (location_t loc, const char *fn
the declaration of the object of which the array is a member or
element. Otherwise return null. */
-tree
+static tree
unterminated_array (tree exp)
{
- if (TREE_CODE (exp) == SSA_NAME)
- {
- gimple *stmt = SSA_NAME_DEF_STMT (exp);
- if (!is_gimple_assign (stmt))
- return NULL_TREE;
-
- tree rhs1 = gimple_assign_rhs1 (stmt);
- tree_code code = gimple_assign_rhs_code (stmt);
- if (code == ADDR_EXPR
- && TREE_CODE (TREE_OPERAND (rhs1, 0)) == ARRAY_REF)
- rhs1 = rhs1;
- else if (code != POINTER_PLUS_EXPR)
- return NULL_TREE;
-
- exp = rhs1;
- }
-
tree nonstr = NULL;
- if (c_strlen (exp, 1, &nonstr, 1) == NULL && nonstr)
- return nonstr;
-
- return NULL_TREE;
+ c_strlen (exp, 1, &nonstr);
+ return nonstr;
}
/* Compute the length of a null-terminated character string or wide
@@ -3936,8 +3917,7 @@ expand_builtin_strcpy_args (tree exp, tree dest, t
if (tree nonstr = unterminated_array (src))
{
/* NONSTR refers to the non-nul terminated constant array. */
- if (!TREE_NO_WARNING (exp))
- warn_string_no_nul (EXPR_LOCATION (exp), "strcpy", src, nonstr);
+ warn_string_no_nul (EXPR_LOCATION (exp), "strcpy", src, nonstr);
return NULL_RTX;
}
@@ -3984,14 +3964,10 @@ expand_builtin_stpcpy_1 (tree exp, rtx target, mac
compile-time, not an expression containing a string. This is
because the latter will potentially produce pessimized code
when used to produce the return value. */
- tree nonstr = NULL_TREE;
if (!c_getstr (src, NULL)
- || !(len = c_strlen (src, 0, &nonstr, 1)))
+ || !(len = c_strlen (src, 0)))
return expand_movstr (dst, src, target, /*endp=*/2);
- if (nonstr && !TREE_NO_WARNING (exp))
- warn_string_no_nul (EXPR_LOCATION (exp), "stpcpy", src, nonstr);
-
lenp1 = size_binop_loc (loc, PLUS_EXPR, len, ssize_int (1));
ret = expand_builtin_mempcpy_args (dst, src, lenp1,
target, exp, /*endp=*/2);
Index: gcc/builtins.h
===================================================================
--- gcc/builtins.h (revision 264342)
+++ gcc/builtins.h (working copy)
@@ -104,7 +104,6 @@ extern internal_fn associated_internal_fn (tree);
extern internal_fn replacement_internal_fn (gcall *);
extern void warn_string_no_nul (location_t, const char *, tree, tree);
-extern tree unterminated_array (tree);
extern tree max_object_size ();
#endif /* GCC_BUILTINS_H */
Index: gcc/expr.c
===================================================================
--- gcc/expr.c (revision 264342)
+++ gcc/expr.c (working copy)
@@ -11372,7 +11372,10 @@ string_constant (tree arg, tree *ptr_offset, tree
/* Avoid pointers to arrays (see bug 86622). */
if (POINTER_TYPE_P (TREE_TYPE (arg))
&& TREE_CODE (TREE_TYPE (TREE_TYPE (arg))) == ARRAY_TYPE
- && TREE_CODE (TREE_OPERAND (arg0, 0)) == ARRAY_REF)
+ && !(decl && !*decl)
+ && !(decl && tree_fits_uhwi_p (DECL_SIZE_UNIT (*decl))
+ && mem_size && tree_fits_uhwi_p (*mem_size)
+ && tree_int_cst_equal (*mem_size, DECL_SIZE_UNIT (*decl))))
return NULL_TREE;
tree type = TREE_TYPE (arg1);
@@ -11381,6 +11384,38 @@ string_constant (tree arg, tree *ptr_offset, tree
}
return NULL_TREE;
}
+ else if (TREE_CODE (arg) == SSA_NAME)
+ {
+ gimple *stmt = SSA_NAME_DEF_STMT (arg);
+ if (!is_gimple_assign (stmt))
+ return NULL_TREE;
+
+ tree rhs1 = gimple_assign_rhs1 (stmt);
+ tree_code code = gimple_assign_rhs_code (stmt);
+ if (code == ADDR_EXPR)
+ return string_constant (rhs1, ptr_offset, mem_size, decl);
+ else if (code != POINTER_PLUS_EXPR)
+ return NULL_TREE;
+
+ tree offset;
+ if (tree str = string_constant (rhs1, &offset, mem_size, decl))
+ {
+ /* Avoid pointers to arrays (see bug 86622). */
+ if (POINTER_TYPE_P (TREE_TYPE (rhs1))
+ && TREE_CODE (TREE_TYPE (TREE_TYPE (rhs1))) == ARRAY_TYPE
+ && !(decl && !*decl)
+ && !(decl && tree_fits_uhwi_p (DECL_SIZE_UNIT (*decl))
+ && mem_size && tree_fits_uhwi_p (*mem_size)
+ && tree_int_cst_equal (*mem_size, DECL_SIZE_UNIT (*decl))))
+ return NULL_TREE;
+
+ tree rhs2 = gimple_assign_rhs2 (stmt);
+ tree type = TREE_TYPE (rhs2);
+ *ptr_offset = fold_build2 (PLUS_EXPR, type, offset, rhs2);
+ return str;
+ }
+ return NULL_TREE;
+ }
else if (DECL_P (arg))
array = arg;
else
Index: gcc/gimple-fold.c
===================================================================
--- gcc/gimple-fold.c (revision 264342)
+++ gcc/gimple-fold.c (working copy)
@@ -1573,11 +1573,6 @@ get_range_strlen (tree arg, tree minmaxlen[2], uns
minmaxlen[0] = NULL_TREE;
minmaxlen[1] = NULL_TREE;
- tree nonstrbuf;
- if (!nonstr)
- nonstr = &nonstrbuf;
- *nonstr = NULL_TREE;
-
bool flexarray = false;
if (!get_range_strlen (arg, minmaxlen, &visited, 1, strict ? 1 : 2,
&flexarray, eltsize, nonstr))
@@ -1607,24 +1602,12 @@ get_maxval_strlen (tree arg, int type, tree *nonst
tree len[2] = { NULL_TREE, NULL_TREE };
bool dummy;
- /* Set to non-null if ARG refers to an untermianted array. */
- tree mynonstr = NULL_TREE;
- if (!get_range_strlen (arg, len, &visited, type, 0, &dummy, 1, &mynonstr))
+ if (!get_range_strlen (arg, len, &visited, type, 0, &dummy, 1, nonstr))
len[1] = NULL_TREE;
if (visited)
BITMAP_FREE (visited);
- if (nonstr)
- {
- /* For callers prepared to handle unterminated arrays set
- *NONSTR to point to the declaration of the array and return
- the maximum length/size. */
- *nonstr = mynonstr;
- return len[1];
- }
-
- /* Fail if the constant array isn't nul-terminated. */
- return mynonstr ? NULL_TREE : len[1];
+ return len[1];
}
@@ -1672,13 +1655,7 @@ gimple_fold_builtin_strcpy (gimple_stmt_iterator *
tree len = get_maxval_strlen (src, 0, &nonstr);
if (nonstr)
- {
- /* Avoid folding calls with unterminated arrays. */
- if (!gimple_no_warning_p (stmt))
- warn_string_no_nul (loc, "strcpy", src, nonstr);
- gimple_set_no_warning (stmt, true);
- return false;
- }
+ warn_string_no_nul (loc, "strcpy", src, nonstr);
if (!len)
return false;
@@ -2813,24 +2790,15 @@ gimple_fold_builtin_stpcpy (gimple_stmt_iterator *
/* Set to non-null if ARG refers to an unterminated array. */
tree nonstr = NULL;
- tree len = c_strlen (src, 1, &nonstr, 1);
+ tree len = c_strlen (src, 1, &nonstr);
+
+ if (nonstr)
+ warn_string_no_nul (loc, "stpcpy", src, nonstr);
+
if (!len
|| TREE_CODE (len) != INTEGER_CST)
- {
- nonstr = unterminated_array (src);
- if (!nonstr)
- return false;
- }
+ return false;
- if (nonstr)
- {
- /* Avoid folding calls with unterminated arrays. */
- if (!gimple_no_warning_p (stmt))
- warn_string_no_nul (loc, "stpcpy", src, nonstr);
- gimple_set_no_warning (stmt, true);
- return false;
- }
-
if (optimize_function_for_size_p (cfun)
/* If length is zero it's small enough. */
&& !integer_zerop (len))
@@ -3093,11 +3061,6 @@ gimple_fold_builtin_sprintf (gimple_stmt_iterator
gimple_seq stmts = NULL;
gimple *repl = gimple_build_call (fn, 2, dest, fmt);
- /* Propagate the NO_WARNING bit to avoid issuing the same
- warning more than once. */
- if (gimple_no_warning_p (stmt))
- gimple_set_no_warning (repl, true);
-
gimple_seq_add_stmt_without_update (&stmts, repl);
if (gimple_call_lhs (stmt))
{
@@ -3147,11 +3110,6 @@ gimple_fold_builtin_sprintf (gimple_stmt_iterator
gimple_seq stmts = NULL;
gimple *repl = gimple_build_call (fn, 2, dest, orig);
- /* Propagate the NO_WARNING bit to avoid issuing the same
- warning more than once. */
- if (gimple_no_warning_p (stmt))
- gimple_set_no_warning (repl, true);
-
gimple_seq_add_stmt_without_update (&stmts, repl);
if (gimple_call_lhs (stmt))
{
@@ -3582,10 +3540,8 @@ gimple_fold_builtin_strlen (gimple_stmt_iterator *
wide_int minlen;
wide_int maxlen;
- /* Set to non-null if ARG refers to an unterminated array. */
- tree nonstr;
tree lenrange[2];
- if (!get_range_strlen (arg, lenrange, 1, true, &nonstr)
+ if (!get_range_strlen (arg, lenrange, 1, true)
&& lenrange[0] && TREE_CODE (lenrange[0]) == INTEGER_CST
&& lenrange[1] && TREE_CODE (lenrange[1]) == INTEGER_CST)
{
Index: gcc/testsuite/gcc.dg/warn-stpcpy-no-nul.c
===================================================================
--- gcc/testsuite/gcc.dg/warn-stpcpy-no-nul.c (revision 264342)
+++ gcc/testsuite/gcc.dg/warn-stpcpy-no-nul.c (working copy)
@@ -71,13 +71,13 @@ void test_two_dim_array (char *d)
T (&b[3][1] + 1); /* { dg-warning "nul" } */
T (&b[3][v0]); /* { dg-warning "nul" } */
T (&b[3][1] + v0); /* { dg-warning "nul" } */
- T (&b[3][v0] + v1); /* { dg-warning "nul" "bug ???" { xfail *-*-* } } */
+ T (&b[3][v0] + v1); /* { dg-warning "nul" } */
T (&b[i3][i1]); /* { dg-warning "nul" } */
T (&b[i3][i1] + i1); /* { dg-warning "nul" } */
T (&b[i3][v0]); /* { dg-warning "nul" } */
T (&b[i3][i1] + v0); /* { dg-warning "nul" } */
- T (&b[i3][v0] + v1); /* { dg-warning "nul" "bug ???" { xfail *-*-* } } */
+ T (&b[i3][v0] + v1); /* { dg-warning "nul" } */
T (v0 ? "" : b[0]);
T (v0 ? "" : b[1]);
Index: gcc/testsuite/gcc.dg/warn-strlen-no-nul.c
===================================================================
--- gcc/testsuite/gcc.dg/warn-strlen-no-nul.c (revision 264342)
+++ gcc/testsuite/gcc.dg/warn-strlen-no-nul.c (working copy)
@@ -71,9 +71,9 @@ T (&b[3][v0] + v1); /* { dg-warning "nul" } *
T (&b[i3][i1]); /* { dg-warning "nul" } */
T (&b[i3][i1] + 1); /* { dg-warning "nul" } */
T (&b[i3][i1] + i1); /* { dg-warning "nul" } */
-T (&b[i3][v0]); /* { dg-warning "nul" "pr86919" { xfail *-*-* } } */
-T (&b[i3][i1] + v0); /* { dg-warning "nul" "pr86919" { xfail *-*-* } } */
-T (&b[i3][v0] + v1); /* { dg-warning "nul" "pr86919" { xfail *-*-* } } */
+T (&b[i3][v0]); /* { dg-warning "nul" } */
+T (&b[i3][i1] + v0); /* { dg-warning "nul" } */
+T (&b[i3][v0] + v1); /* { dg-warning "nul" } */
T (v0 ? "" : b[0]);
T (v0 ? "" : b[1]);
@@ -152,10 +152,10 @@ T (&s.b[1] + v0); /* { dg-warning "nul" } */
T (&s.b[i0]); /* { dg-warning "nul" } */
T (&s.b[i0] + i1); /* { dg-warning "nul" } */
-T (&s.b[i0] + v0); /* { dg-warning "nul" "pr86919" { xfail *-*-* } } */
+T (&s.b[i0] + v0); /* { dg-warning "nul" } */
T (&s.b[i1]); /* { dg-warning "nul" } */
T (&s.b[i1] + i1); /* { dg-warning "nul" } */
-T (&s.b[i1] + v0); /* { dg-warning "nul" "pr86919" { xfail *-*-* } } */
+T (&s.b[i1] + v0); /* { dg-warning "nul" } */
struct B { struct A a[2]; };