[PATCH] D132406: [LibCalls] Mark puts/printf/perror as inaccessible_mem_or_argmem.

[Florian Hahn via Phabricator via llvm-commits]

fhahn created this revision.
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Unless I am missing something, those functions should only access
either memory accessible through their arguments or inaccessible memory.

If I am not missing anything, it would probably be worth to add that
attribute to most libcalls.


Repository:
  rG LLVM Github Monorepo

https://reviews.llvm.org/D132406

Files:
  llvm/lib/Transforms/Utils/BuildLibCalls.cpp
  llvm/test/Transforms/InferFunctionAttrs/annotate.ll


Index: llvm/test/Transforms/InferFunctionAttrs/annotate.ll
===================================================================
--- llvm/test/Transforms/InferFunctionAttrs/annotate.ll
+++ llvm/test/Transforms/InferFunctionAttrs/annotate.ll
@@ -739,8 +739,7 @@
 
 ; CHECK: declare noundef i32 @pclose(%opaque* nocapture noundef) [[NOFREE_NOUNWIND]]
 declare i32 @pclose(%opaque*)
-
-; CHECK: declare void @perror(i8* nocapture noundef readonly) [[NOFREE_NOUNWIND]]
+; CHECK: declare void @perror(i8* nocapture noundef readonly) [[INACCESSIBLEMEMORARGONLY_NOFREE_NOUNWIND:#[0-9]+]]
 declare void @perror(i8*)
 
 ; CHECK: declare noalias noundef %opaque* @popen(i8* nocapture noundef readonly, i8* nocapture noundef readonly) [[NOFREE_NOUNWIND]]
@@ -761,7 +760,7 @@
 ; CHECK: declare noundef i64 @pread(i32 noundef, i8* nocapture noundef, i64 noundef, i64 noundef) [[NOFREE]]
 declare i64 @pread(i32, i8*, i64, i64)
 
-; CHECK: declare noundef i32 @printf(i8* nocapture noundef readonly, ...) [[NOFREE_NOUNWIND]]
+; CHECK: declare noundef i32 @printf(i8* nocapture noundef readonly, ...) [[INACCESSIBLEMEMORARGONLY_NOFREE_NOUNWIND]]
 declare i32 @printf(i8*, ...)
 
 ; CHECK: declare noundef i32 @putc(i32 noundef, %opaque* nocapture noundef) [[NOFREE_NOUNWIND]]
@@ -774,7 +773,7 @@
 ; CHECK-UNKNOWN: declare i32 @putchar_unlocked(i32){{$}}
 declare i32 @putchar_unlocked(i32)
 
-; CHECK: declare noundef i32 @puts(i8* nocapture noundef readonly) [[NOFREE_NOUNWIND]]
+; CHECK: declare noundef i32 @puts(i8* nocapture noundef readonly) [[INACCESSIBLEMEMORARGONLY_NOFREE_NOUNWIND]]
 declare i32 @puts(i8*)
 
 ; CHECK: declare noundef i64 @pwrite(i32 noundef, i8* nocapture noundef readonly, i64 noundef, i64 noundef) [[NOFREE]]
@@ -1096,6 +1095,7 @@
 ; CHECK-DAG: attributes [[ARGMEMONLY_NOFREE_NOUNWIND]] = { argmemonly nofree nounwind }
 ; CHECK-DAG: attributes [[INACCESSIBLEMEMORARGMEMONLY_NOUNWIND_WILLRETURN_ALLOCKIND_REALLOC_ALLOCSIZE1_FAMILY_MALLOC]] = { inaccessiblemem_or_argmemonly mustprogress nounwind willreturn allockind("realloc") allocsize(1) "alloc-family"="malloc" }
 ; CHECK-DAG: attributes [[INACCESSIBLEMEMORARGONLY_NOFREE_NOUNWIND_WILLRETURN_FAMILY_MALLOC]] = { inaccessiblemem_or_argmemonly mustprogress nofree nounwind willreturn "alloc-family"="malloc" }
+; CHECK-DAG: attributes [[INACCESSIBLEMEMORARGONLY_NOFREE_NOUNWIND]] = { inaccessiblemem_or_argmemonly nofree nounwind }
 
 ; CHECK-NVPTX-DAG: attributes [[NOFREE_NOUNWIND_READNONE]] = { nofree nosync nounwind readnone }
 
Index: llvm/lib/Transforms/Utils/BuildLibCalls.cpp
===================================================================
--- llvm/lib/Transforms/Utils/BuildLibCalls.cpp
+++ llvm/lib/Transforms/Utils/BuildLibCalls.cpp
@@ -860,6 +860,7 @@
     Changed |= setRetAndArgsNoUndef(F);
     Changed |= setDoesNotThrow(F);
     Changed |= setDoesNotCapture(F, 0);
+    Changed |= setOnlyAccessesInaccessibleMemOrArgMem(F);
     Changed |= setOnlyReadsMemory(F, 0);
     break;
   case LibFunc_pread:


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