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[BuildLibCalls] Add noalias for strcat and stpcpy 

strcat:
destination and source shall not overlap. (http://www.cplusplus.com/reference/cstring/strcat/)

stpcpy:
The strings may not overlap, and the destination string dest must be  large enough to receive the copy. (https://man7.org/linux/man-pages/man3/stpcpy.3.html)

Reviewed By: jdoerfert

Differential Revision: https://reviews.llvm.org/D88335
This commit is contained in:
Dávid Bolvanský 2020-09-27 21:32:32 +02:00
parent 0103df7903
commit 155ac33394
2 changed files with 6 additions and 7 deletions
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5
llvm/lib/Transforms/Utils/BuildLibCalls.cpp
View File

@ -203,9 +203,6 @@ bool llvm::inferLibFuncAttributes(Function &F, const TargetLibraryInfo &TLI) {
return Changed;
case LibFunc_strcpy:
case LibFunc_strncpy:
Changed |= setDoesNotAlias(F, 0);
Changed |= setDoesNotAlias(F, 1);
LLVM_FALLTHROUGH;
case LibFunc_strcat:
case LibFunc_strncat:
Changed |= setReturnedArg(F, 0);
@ -215,6 +212,8 @@ bool llvm::inferLibFuncAttributes(Function &F, const TargetLibraryInfo &TLI) {
Changed |= setDoesNotThrow(F);
Changed |= setDoesNotCapture(F, 1);
Changed |= setOnlyReadsMemory(F, 1);
Changed |= setDoesNotAlias(F, 0);
Changed |= setDoesNotAlias(F, 1);
return Changed;
case LibFunc_strxfrm:
Changed |= setDoesNotThrow(F);

8
llvm/test/Transforms/InferFunctionAttrs/annotate.ll
View File

@ -825,16 +825,16 @@ declare i32 @statvfs(i8*, %opaque*)
; CHECK-LINUX: declare noundef i32 @statvfs64(i8* nocapture noundef readonly, %opaque* nocapture noundef) [[G1]]
declare i32 @statvfs64(i8*, %opaque*)
; CHECK: declare i8* @stpcpy(i8*, i8* nocapture readonly) [[G1]]
; CHECK: declare i8* @stpcpy(i8* noalias, i8* noalias nocapture readonly) [[G1]]
declare i8* @stpcpy(i8*, i8*)
; CHECK: declare i8* @stpncpy(i8*, i8* nocapture readonly, i64) [[G1]]
; CHECK: declare i8* @stpncpy(i8* noalias, i8* noalias nocapture readonly, i64) [[G1]]
declare i8* @stpncpy(i8*, i8*, i64)
; CHECK: declare i32 @strcasecmp(i8* nocapture, i8* nocapture) [[G2]]
declare i32 @strcasecmp(i8*, i8*)
; CHECK: declare i8* @strcat(i8* returned, i8* nocapture readonly) [[G1]]
; CHECK: declare i8* @strcat(i8* noalias returned, i8* noalias nocapture readonly) [[G1]]
declare i8* @strcat(i8*, i8*)
; CHECK: declare i8* @strchr(i8*, i32) [[ARGMEMONLY_NOFREE_NOUNWIND_READONLY]]
@ -861,7 +861,7 @@ declare i64 @strlen(i8*)
; CHECK: declare i32 @strncasecmp(i8* nocapture, i8* nocapture, i64) [[G2]]
declare i32 @strncasecmp(i8*, i8*, i64)
; CHECK: declare i8* @strncat(i8* returned, i8* nocapture readonly, i64) [[G1]]
; CHECK: declare i8* @strncat(i8* noalias returned, i8* noalias nocapture readonly, i64) [[G1]]
declare i8* @strncat(i8*, i8*, i64)
; CHECK: declare i32 @strncmp(i8* nocapture, i8* nocapture, i64) [[ARGMEMONLY_NOFREE_NOUNWIND_READONLY]]