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[Analysis] improve function signature checking for snprintf

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The check for size_t parameter 1 was already here for snprintf_chk,
but it wasn't applied to regular snprintf. This could lead to
mismatching and eventually crashing as shown in:
https://llvm.org/PR50885

(cherry picked from commit 7f5555776513f174729a686ed01270e23462aaf7)
This commit is contained in:
Sanjay Patel 2021-07-31 15:13:42 -04:00 committed by Tom Stellard
parent 9770d34891
commit d4eedb2312
2 changed files with 16 additions and 3 deletions
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7
lib/Analysis/TargetLibraryInfo.cpp
View File

@ -893,9 +893,10 @@ bool TargetLibraryInfoImpl::isValidProtoForLibFunc(const FunctionType &FTy,
FTy.getReturnType()->isIntegerTy(32);
case LibFunc_snprintf:
return (NumParams == 3 && FTy.getParamType(0)->isPointerTy() &&
FTy.getParamType(2)->isPointerTy() &&
FTy.getReturnType()->isIntegerTy(32));
return NumParams == 3 && FTy.getParamType(0)->isPointerTy() &&
IsSizeTTy(FTy.getParamType(1)) &&
FTy.getParamType(2)->isPointerTy() &&
FTy.getReturnType()->isIntegerTy(32);
case LibFunc_snprintf_chk:
return NumParams == 5 && FTy.getParamType(0)->isPointerTy() &&

12
test/Transforms/InstCombine/simplify-libcalls.ll
View File

@ -217,6 +217,18 @@ define double @fake_ldexp_16(i16 %x) {
ret double %z
}
; PR50885 - this would crash in ValueTracking.
declare i32 @snprintf(i8*, double, i32*)
define i32 @fake_snprintf(i32 %buf, double %len, i32 * %str) {
; CHECK-LABEL: @fake_snprintf(
; CHECK-NEXT: [[CALL:%.*]] = call i32 @snprintf(i8* undef, double [[LEN:%.*]], i32* [[STR:%.*]])
; CHECK-NEXT: ret i32 [[CALL]]
;
%call = call i32 @snprintf(i8* undef, double %len, i32* %str)
ret i32 %call
}
attributes #0 = { nobuiltin }
attributes #1 = { builtin }