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[InferAttrs] Add nocapture/writeonly to string/mem libcalls
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One step closer to fix PR47644.

Differential Revision: https://reviews.llvm.org/D89645
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@davidbolvansky
davidbolvansky committed Oct 29, 2020
1 parent 05f7b68 commit 7a2abf5
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Showing 4 changed files with 40 additions and 20 deletions.
21 changes: 20 additions & 1 deletion llvm/lib/Transforms/Utils/BuildLibCalls.cpp
View file
Expand Up @@ -35,6 +35,7 @@ STATISTIC(NumReadOnly, "Number of functions inferred as readonly");
STATISTIC(NumArgMemOnly, "Number of functions inferred as argmemonly");
STATISTIC(NumNoUnwind, "Number of functions inferred as nounwind");
STATISTIC(NumNoCapture, "Number of arguments inferred as nocapture");
STATISTIC(NumWriteOnlyArg, "Number of arguments inferred as writeonly");
STATISTIC(NumReadOnlyArg, "Number of arguments inferred as readonly");
STATISTIC(NumNoAlias, "Number of function returns inferred as noalias");
STATISTIC(NumNoUndef, "Number of function returns inferred as noundef returns");
Expand Down Expand Up @@ -105,6 +106,15 @@ static bool setOnlyReadsMemory(Function &F, unsigned ArgNo) {
return true;
}

static bool setOnlyWritesMemory(Function &F, unsigned ArgNo) {
if (F.hasParamAttribute(ArgNo, Attribute::WriteOnly))
return false;
F.addParamAttr(ArgNo, Attribute::WriteOnly);
++NumWriteOnlyArg;
return true;
}


static bool setRetNoUndef(Function &F) {
if (!F.getReturnType()->isVoidTy() &&
!F.hasAttribute(AttributeList::ReturnIndex, Attribute::NoUndef)) {
Expand Down Expand Up @@ -220,6 +230,7 @@ bool llvm::inferLibFuncAttributes(Function &F, const TargetLibraryInfo &TLI) {
Changed |= setOnlyAccessesArgMemory(F);
Changed |= setDoesNotThrow(F);
Changed |= setDoesNotCapture(F, 1);
Changed |= setOnlyWritesMemory(F, 0);
Changed |= setOnlyReadsMemory(F, 1);
Changed |= setDoesNotAlias(F, 0);
Changed |= setDoesNotAlias(F, 1);
Expand Down Expand Up @@ -303,6 +314,7 @@ bool llvm::inferLibFuncAttributes(Function &F, const TargetLibraryInfo &TLI) {
Changed |= setDoesNotThrow(F);
Changed |= setDoesNotCapture(F, 0);
Changed |= setDoesNotAlias(F, 0);
Changed |= setOnlyWritesMemory(F, 0);
Changed |= setDoesNotCapture(F, 1);
Changed |= setOnlyReadsMemory(F, 1);
return Changed;
Expand All @@ -311,6 +323,7 @@ bool llvm::inferLibFuncAttributes(Function &F, const TargetLibraryInfo &TLI) {
Changed |= setDoesNotThrow(F);
Changed |= setDoesNotCapture(F, 0);
Changed |= setDoesNotAlias(F, 0);
Changed |= setOnlyWritesMemory(F, 0);
Changed |= setDoesNotCapture(F, 2);
Changed |= setOnlyReadsMemory(F, 2);
return Changed;
Expand Down Expand Up @@ -356,6 +369,7 @@ bool llvm::inferLibFuncAttributes(Function &F, const TargetLibraryInfo &TLI) {
Changed |= setOnlyAccessesArgMemory(F);
Changed |= setDoesNotAlias(F, 0);
Changed |= setReturnedArg(F, 0);
Changed |= setOnlyWritesMemory(F, 0);
Changed |= setDoesNotAlias(F, 1);
Changed |= setDoesNotCapture(F, 1);
Changed |= setOnlyReadsMemory(F, 1);
Expand All @@ -364,6 +378,7 @@ bool llvm::inferLibFuncAttributes(Function &F, const TargetLibraryInfo &TLI) {
Changed |= setDoesNotThrow(F);
Changed |= setOnlyAccessesArgMemory(F);
Changed |= setReturnedArg(F, 0);
Changed |= setOnlyWritesMemory(F, 0);
Changed |= setDoesNotCapture(F, 1);
Changed |= setOnlyReadsMemory(F, 1);
return Changed;
Expand All @@ -372,6 +387,7 @@ bool llvm::inferLibFuncAttributes(Function &F, const TargetLibraryInfo &TLI) {
Changed |= setDoesNotThrow(F);
Changed |= setOnlyAccessesArgMemory(F);
Changed |= setDoesNotAlias(F, 0);
Changed |= setOnlyWritesMemory(F, 0);
Changed |= setDoesNotAlias(F, 1);
Changed |= setDoesNotCapture(F, 1);
Changed |= setOnlyReadsMemory(F, 1);
Expand Down Expand Up @@ -450,8 +466,9 @@ bool llvm::inferLibFuncAttributes(Function &F, const TargetLibraryInfo &TLI) {
Changed |= setDoesNotThrow(F);
Changed |= setOnlyAccessesArgMemory(F);
Changed |= setDoesNotCapture(F, 0);
Changed |= setDoesNotCapture(F, 1);
Changed |= setOnlyReadsMemory(F, 0);
Changed |= setOnlyWritesMemory(F, 1);
Changed |= setDoesNotCapture(F, 1);
return Changed;
case LibFunc_bcmp:
Changed |= setDoesNotThrow(F);
Expand All @@ -464,6 +481,7 @@ bool llvm::inferLibFuncAttributes(Function &F, const TargetLibraryInfo &TLI) {
Changed |= setDoesNotThrow(F);
Changed |= setOnlyAccessesArgMemory(F);
Changed |= setDoesNotCapture(F, 0);
Changed |= setOnlyWritesMemory(F, 0);
return Changed;
case LibFunc_calloc:
Changed |= setRetNoUndef(F);
Expand Down Expand Up @@ -922,6 +940,7 @@ bool llvm::inferLibFuncAttributes(Function &F, const TargetLibraryInfo &TLI) {
case LibFunc_memset_pattern16:
Changed |= setOnlyAccessesArgMemory(F);
Changed |= setDoesNotCapture(F, 0);
Changed |= setOnlyWritesMemory(F, 0);
Changed |= setDoesNotCapture(F, 1);
Changed |= setOnlyReadsMemory(F, 1);
return Changed;
Expand Down
7 changes: 4 additions & 3 deletions llvm/test/Analysis/BasicAA/libfuncs.ll
View file
Expand Up @@ -106,13 +106,14 @@ entry:
declare i8* @memccpy(i8*, i8*, i32, i64)

; CHECK-LABEL: Function: test_memccpy_const_size
; CHECK: Both ModRef: Ptr: i8* %a <-> %res = call i8* @memccpy(i8* %a, i8* %b, i32 42, i64 4)
; CHECK: Just Mod: Ptr: i8* %a <-> %res = call i8* @memccpy(i8* %a, i8* %b, i32 42, i64 4)
; CHECK-NEXT: Just Ref: Ptr: i8* %b <-> %res = call i8* @memccpy(i8* %a, i8* %b, i32 42, i64 4)
; CHECK-NEXT: Both ModRef: Ptr: i8* %res <-> %res = call i8* @memccpy(i8* %a, i8* %b, i32 42, i64 4)
; CHECK-NEXT: Both ModRef: Ptr: i8* %a.gep.1 <-> %res = call i8* @memccpy(i8* %a, i8* %b, i32 42, i64 4)
; CHECK-NEXT: Just Mod: Ptr: i8* %res <-> %res = call i8* @memccpy(i8* %a, i8* %b, i32 42, i64 4)
; CHECK-NEXT: Just Mod: Ptr: i8* %a.gep.1 <-> %res = call i8* @memccpy(i8* %a, i8* %b, i32 42, i64 4)
; CHECK-NEXT: NoModRef: Ptr: i8* %a.gep.5 <-> %res = call i8* @memccpy(i8* %a, i8* %b, i32 42, i64 4)
; CHECK-NEXT: Just Ref: Ptr: i8* %b.gep.1 <-> %res = call i8* @memccpy(i8* %a, i8* %b, i32 42, i64 4)
; CHECK-NEXT: NoModRef: Ptr: i8* %b.gep.5 <-> %res = call i8* @memccpy(i8* %a, i8* %b, i32 42, i64 4)

define i8* @test_memccpy_const_size(i8* noalias %a, i8* noalias %b) {
entry:
%res = call i8* @memccpy(i8* %a, i8* %b, i32 42, i64 4)
Expand Down
30 changes: 15 additions & 15 deletions llvm/test/Transforms/InferFunctionAttrs/annotate.ll
View file
Expand Up @@ -247,10 +247,10 @@ declare i64 @atoll(i8*)
; CHECK-NVPTX-NOT: declare i32 @bcmp(i8* nocapture, i8* nocapture, i64) [[G2]]
declare i32 @bcmp(i8*, i8*, i64)

; CHECK: declare void @bcopy(i8* nocapture readonly, i8* nocapture, i64) [[ARGMEMONLY_NOFREE_NOUNWIND:#[0-9]+]]
; CHECK: declare void @bcopy(i8* nocapture readonly, i8* nocapture writeonly, i64) [[ARGMEMONLY_NOFREE_NOUNWIND:#[0-9]+]]
declare void @bcopy(i8*, i8*, i64)

; CHECK: declare void @bzero(i8* nocapture, i64) [[ARGMEMONLY_NOFREE_NOUNWIND:#[0-9]+]]
; CHECK: declare void @bzero(i8* nocapture writeonly, i64) [[ARGMEMONLY_NOFREE_NOUNWIND:#[0-9]+]]
declare void @bzero(i8*, i64)

; CHECK: declare noalias noundef i8* @calloc(i64, i64) [[G1]]
Expand Down Expand Up @@ -619,7 +619,7 @@ declare i8* @malloc(i64)
; CHECK-LINUX: declare noalias i8* @memalign(i64, i64) [[G0]]
declare i8* @memalign(i64, i64)

; CHECK: declare i8* @memccpy(i8* noalias, i8* noalias nocapture readonly, i32, i64) [[ARGMEMONLY_NOFREE_NOUNWIND:#[0-9]+]]
; CHECK: declare i8* @memccpy(i8* noalias writeonly, i8* noalias nocapture readonly, i32, i64) [[ARGMEMONLY_NOFREE_NOUNWIND:#[0-9]+]]
declare i8* @memccpy(i8*, i8*, i32, i64)

; CHECK-LINUX: declare i8* @memchr(i8*, i32, i64) [[ARGMEMONLY_NOFREE_NOUNWIND_READONLY]]
Expand All @@ -630,13 +630,13 @@ declare i8* @memchr(i8*, i32, i64)
; CHECK: declare i32 @memcmp(i8* nocapture, i8* nocapture, i64) [[ARGMEMONLY_NOFREE_NOUNWIND_READONLY]]
declare i32 @memcmp(i8*, i8*, i64)

; CHECK: declare i8* @memcpy(i8* noalias returned, i8* noalias nocapture readonly, i64) [[ARGMEMONLY_NOFREE_NOUNWIND]]
; CHECK: declare i8* @memcpy(i8* noalias returned writeonly, i8* noalias nocapture readonly, i64) [[ARGMEMONLY_NOFREE_NOUNWIND]]
declare i8* @memcpy(i8*, i8*, i64)

; CHECK: declare i8* @mempcpy(i8* noalias, i8* noalias nocapture readonly, i64) [[ARGMEMONLY_NOFREE_NOUNWIND]]
; CHECK: declare i8* @mempcpy(i8* noalias writeonly, i8* noalias nocapture readonly, i64) [[ARGMEMONLY_NOFREE_NOUNWIND]]
declare i8* @mempcpy(i8*, i8*, i64)

; CHECK: declare i8* @memmove(i8* returned, i8* nocapture readonly, i64) [[ARGMEMONLY_NOFREE_NOUNWIND]]
; CHECK: declare i8* @memmove(i8* returned writeonly, i8* nocapture readonly, i64) [[ARGMEMONLY_NOFREE_NOUNWIND]]
declare i8* @memmove(i8*, i8*, i64)

; CHECK: declare i8* @memset(i8*, i32, i64) [[G0]]
Expand Down Expand Up @@ -795,10 +795,10 @@ declare x86_fp80 @sinhl(x86_fp80)
; CHECK: declare x86_fp80 @sinl(x86_fp80) [[G0]]
declare x86_fp80 @sinl(x86_fp80)

; CHECK: declare noundef i32 @snprintf(i8* noalias nocapture noundef, i64 noundef, i8* nocapture noundef readonly, ...) [[G1]]
; CHECK: declare noundef i32 @snprintf(i8* noalias nocapture noundef writeonly, i64 noundef, i8* nocapture noundef readonly, ...) [[G1]]
declare i32 @snprintf(i8*, i64, i8*, ...)

; CHECK: declare noundef i32 @sprintf(i8* noalias nocapture noundef, i8* nocapture noundef readonly, ...) [[G1]]
; CHECK: declare noundef i32 @sprintf(i8* noalias nocapture noundef writeonly, i8* nocapture noundef readonly, ...) [[G1]]
declare i32 @sprintf(i8*, i8*, ...)

; CHECK: declare double @sqrt(double) [[G0]]
Expand All @@ -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* noalias, i8* noalias nocapture readonly) [[ARGMEMONLY_NOFREE_NOUNWIND]]
; CHECK: declare i8* @stpcpy(i8* noalias writeonly, i8* noalias nocapture readonly) [[ARGMEMONLY_NOFREE_NOUNWIND]]
declare i8* @stpcpy(i8*, i8*)

; CHECK: declare i8* @stpncpy(i8* noalias, i8* noalias nocapture readonly, i64) [[ARGMEMONLY_NOFREE_NOUNWIND]]
; CHECK: declare i8* @stpncpy(i8* noalias writeonly, i8* noalias nocapture readonly, i64) [[ARGMEMONLY_NOFREE_NOUNWIND]]
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* noalias returned, i8* noalias nocapture readonly) [[ARGMEMONLY_NOFREE_NOUNWIND]]
; CHECK: declare i8* @strcat(i8* noalias returned writeonly, i8* noalias nocapture readonly) [[ARGMEMONLY_NOFREE_NOUNWIND]]
declare i8* @strcat(i8*, i8*)

; CHECK: declare i8* @strchr(i8*, i32) [[ARGMEMONLY_NOFREE_NOUNWIND_READONLY]]
Expand All @@ -846,7 +846,7 @@ declare i32 @strcmp(i8*, i8*)
; CHECK: declare i32 @strcoll(i8* nocapture, i8* nocapture) [[G2]]
declare i32 @strcoll(i8*, i8*)

; CHECK: declare i8* @strcpy(i8* noalias returned, i8* noalias nocapture readonly) [[ARGMEMONLY_NOFREE_NOUNWIND]]
; CHECK: declare i8* @strcpy(i8* noalias returned writeonly, i8* noalias nocapture readonly) [[ARGMEMONLY_NOFREE_NOUNWIND]]
declare i8* @strcpy(i8*, i8*)

; CHECK: declare i64 @strcspn(i8* nocapture, i8* nocapture) [[ARGMEMONLY_NOFREE_NOUNWIND_READONLY]]
Expand All @@ -861,13 +861,13 @@ 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* noalias returned, i8* noalias nocapture readonly, i64) [[ARGMEMONLY_NOFREE_NOUNWIND]]
; CHECK: declare i8* @strncat(i8* noalias returned writeonly, i8* noalias nocapture readonly, i64) [[ARGMEMONLY_NOFREE_NOUNWIND]]
declare i8* @strncat(i8*, i8*, i64)

; CHECK: declare i32 @strncmp(i8* nocapture, i8* nocapture, i64) [[ARGMEMONLY_NOFREE_NOUNWIND_READONLY]]
declare i32 @strncmp(i8*, i8*, i64)

; CHECK: declare i8* @strncpy(i8* noalias returned, i8* noalias nocapture readonly, i64) [[ARGMEMONLY_NOFREE_NOUNWIND]]
; CHECK: declare i8* @strncpy(i8* noalias returned writeonly, i8* noalias nocapture readonly, i64) [[ARGMEMONLY_NOFREE_NOUNWIND]]
declare i8* @strncpy(i8*, i8*, i64)

; CHECK: declare noalias i8* @strndup(i8* nocapture readonly, i64) [[G1]]
Expand Down Expand Up @@ -1007,7 +1007,7 @@ declare i64 @write(i32, i8*, i64)


; memset_pattern16 isn't available everywhere.
; CHECK-DARWIN: declare void @memset_pattern16(i8* nocapture, i8* nocapture readonly, i64) [[ARGMEMONLY_NOFREE:#[0-9]+]]
; CHECK-DARWIN: declare void @memset_pattern16(i8* nocapture writeonly, i8* nocapture readonly, i64) [[ARGMEMONLY_NOFREE:#[0-9]+]]
declare void @memset_pattern16(i8*, i8*, i64)

; CHECK: attributes [[G0]] = { nofree }
Expand Down
2 changes: 1 addition & 1 deletion llvm/test/Transforms/LoopIdiom/basic.ll
View file
Expand Up @@ -1064,5 +1064,5 @@ exit:
}

; Validate that "memset_pattern" has the proper attributes.
; CHECK: declare void @memset_pattern16(i8* nocapture, i8* nocapture readonly, i64) [[ATTRS:#[0-9]+]]
; CHECK: declare void @memset_pattern16(i8* nocapture writeonly, i8* nocapture readonly, i64) [[ATTRS:#[0-9]+]]
; CHECK: [[ATTRS]] = { argmemonly nofree }

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