This revision was automatically updated to reflect the committed changes.
Closed by commit rL365407: [Attributor] Deduce the "returned"
argument attribute (authored by jdoerfert, committed by ).
Changed prior to commit:
https://reviews.llvm.org/D59919?vs=207924&id=208536#toc
Repository:
rL LLVM
CHANGES SINCE LAST ACTION
https://reviews.llvm.org/D59919/new/
https://reviews.llvm.org/D59919
Files:
llvm/trunk/include/llvm/Transforms/IPO/Attributor.h
llvm/trunk/lib/Transforms/IPO/Attributor.cpp
llvm/trunk/test/Transforms/FunctionAttrs/arg_nocapture.ll
llvm/trunk/test/Transforms/FunctionAttrs/arg_returned.ll
llvm/trunk/test/Transforms/FunctionAttrs/read_write_returned_arguments_scc.ll
Index: llvm/trunk/include/llvm/Transforms/IPO/Attributor.h
===================================================================
--- llvm/trunk/include/llvm/Transforms/IPO/Attributor.h
+++ llvm/trunk/include/llvm/Transforms/IPO/Attributor.h
@@ -642,6 +642,27 @@
/// Abstract Attribute Classes
/// ----------------------------------------------------------------------------
+/// An abstract attribute for the returned values of a function.
+struct AAReturnedValues : public AbstractAttribute {
+ /// See AbstractAttribute::AbstractAttribute(...).
+ AAReturnedValues(Function &F, InformationCache &InfoCache)
+ : AbstractAttribute(F, InfoCache) {}
+
+ /// Check \p Pred on all returned values.
+ ///
+ /// This method will evaluate \p Pred on returned values and return
+ /// true if (1) all returned values are known, and (2) \p Pred returned true
+ /// for all returned values.
+ virtual bool
+ checkForallReturnedValues(std::function<bool(Value &)> &Pred) const = 0;
+
+ /// See AbstractAttribute::getAttrKind()
+ virtual Attribute::AttrKind getAttrKind() const override { return ID; }
+
+ /// The identifier used by the Attributor for this class of attributes.
+ static constexpr Attribute::AttrKind ID = Attribute::Returned;
+};
+
struct AANoUnwind : public AbstractAttribute {
/// An abstract interface for all nosync attributes.
AANoUnwind(Value &V, InformationCache &InfoCache)
Index: llvm/trunk/test/Transforms/FunctionAttrs/arg_nocapture.ll
===================================================================
--- llvm/trunk/test/Transforms/FunctionAttrs/arg_nocapture.ll
+++ llvm/trunk/test/Transforms/FunctionAttrs/arg_nocapture.ll
@@ -112,18 +112,15 @@
; TEST SCC with various calls, casts, and comparisons agains NULL
;
-; FIXME: returned missing for %a
; FIXME: no-capture missing for %a
-; CHECK: define float* @scc_A(i32* readnone %a)
+; CHECK: define float* @scc_A(i32* readnone returned %a)
;
-; FIXME: returned missing for %a
; FIXME: no-capture missing for %a
-; CHECK: define i64* @scc_B(double* readnone %a)
+; CHECK: define i64* @scc_B(double* readnone returned %a)
;
-; FIXME: returned missing for %a
; FIXME: readnone missing for %s
; FIXME: no-capture missing for %a
-; CHECK: define i8* @scc_C(i16* %a)
+; CHECK: define i8* @scc_C(i16* returned %a)
;
; float *scc_A(int *a) {
; return (float*)(a ? (int*)scc_A((int*)scc_B((double*)scc_C((short*)a))) : a);
Index: llvm/trunk/test/Transforms/FunctionAttrs/arg_returned.ll
===================================================================
--- llvm/trunk/test/Transforms/FunctionAttrs/arg_returned.ll
+++ llvm/trunk/test/Transforms/FunctionAttrs/arg_returned.ll
@@ -1,5 +1,6 @@
-; RUN: opt -functionattrs -attributor -attributor-disable=false -S < %s | FileCheck %s
-; RUN: opt -functionattrs -attributor -attributor-disable=false -attributor-verify=true -S < %s | FileCheck %s
+; RUN: opt -functionattrs -S < %s | FileCheck %s --check-prefix=FNATTR
+; RUN: opt -attributor -attributor-disable=false -S < %s | FileCheck %s --check-prefix=ATTRIBUTOR
+; RUN: opt -attributor -attributor-disable=false -functionattrs -S < %s | FileCheck %s --check-prefix=BOTH
;
; Test cases specifically designed for the "returned" argument attribute.
; We use FIXME's to indicate problems and missing attributes.
@@ -7,16 +8,24 @@
; TEST SCC test returning an integer value argument
;
-; CHECK: Function Attrs: noinline norecurse nounwind readnone uwtable
-; CHECK: define i32 @sink_r0(i32 returned %r)
-;
-; FIXME: returned on %r missing:
-; CHECK: Function Attrs: noinline nounwind readnone uwtable
-; CHECK: define i32 @scc_r1(i32 %a, i32 %r, i32 %b)
-;
-; FIXME: returned on %r missing:
-; CHECK: Function Attrs: noinline nounwind readnone uwtable
-; CHECK: define i32 @scc_r2(i32 %a, i32 %b, i32 %r)
+; BOTH: Function Attrs: noinline norecurse nounwind readnone uwtable
+; BOTH-NEXT: define i32 @sink_r0(i32 returned %r)
+; BOTH: Function Attrs: noinline nounwind readnone uwtable
+; BOTH-NEXT: define i32 @scc_r1(i32 %a, i32 returned %r, i32 %b)
+; BOTH: Function Attrs: noinline nounwind readnone uwtable
+; BOTH-NEXT: define i32 @scc_r2(i32 %a, i32 %b, i32 returned %r)
+; BOTH: Function Attrs: noinline nounwind readnone uwtable
+; BOTH-NEXT: define i32 @scc_rX(i32 %a, i32 %b, i32 %r)
+;
+; FNATTR: define i32 @sink_r0(i32 returned %r)
+; FNATTR: define i32 @scc_r1(i32 %a, i32 %r, i32 %b)
+; FNATTR: define i32 @scc_r2(i32 %a, i32 %b, i32 %r)
+; FNATTR: define i32 @scc_rX(i32 %a, i32 %b, i32 %r)
+;
+; ATTRIBUTOR: define i32 @sink_r0(i32 returned %r)
+; ATTRIBUTOR: define i32 @scc_r1(i32 %a, i32 returned %r, i32 %b)
+; ATTRIBUTOR: define i32 @scc_r2(i32 %a, i32 %b, i32 returned %r)
+; ATTRIBUTOR: define i32 @scc_rX(i32 %a, i32 %b, i32 %r)
;
; int scc_r1(int a, int b, int r);
; int scc_r2(int a, int b, int r);
@@ -150,16 +159,20 @@
; TEST SCC test returning a pointer value argument
;
-; CHECK: Function Attrs: noinline norecurse nounwind readnone uwtable
-; CHECK: define double* @ptr_sink_r0(double* readnone returned %r)
-;
-; FIXME: returned on %r missing:
-; CHECK: Function Attrs: noinline nounwind readnone uwtable
-; CHECK: define double* @ptr_scc_r1(double* %a, double* readnone %r, double* nocapture readnone %b)
-;
-; FIXME: returned on %r missing:
-; CHECK: Function Attrs: noinline nounwind readnone uwtable
-; CHECK: define double* @ptr_scc_r2(double* readnone %a, double* readnone %b, double* readnone %r)
+; BOTH: Function Attrs: noinline norecurse nounwind readnone uwtable
+; BOTH-NEXT: define double* @ptr_sink_r0(double* readnone returned %r)
+; BOTH: Function Attrs: noinline nounwind readnone uwtable
+; BOTH-NEXT: define double* @ptr_scc_r1(double* %a, double* readnone returned %r, double* nocapture readnone %b)
+; BOTH: Function Attrs: noinline nounwind readnone uwtable
+; BOTH-NEXT: define double* @ptr_scc_r2(double* readnone %a, double* readnone %b, double* readnone returned %r)
+;
+; FNATTR: define double* @ptr_sink_r0(double* readnone returned %r)
+; FNATTR: define double* @ptr_scc_r1(double* %a, double* readnone %r, double* nocapture readnone %b)
+; FNATTR: define double* @ptr_scc_r2(double* readnone %a, double* readnone %b, double* readnone %r)
+;
+; ATTRIBUTOR: define double* @ptr_sink_r0(double* returned %r)
+; ATTRIBUTOR: define double* @ptr_scc_r1(double* %a, double* returned %r, double* %b)
+; ATTRIBUTOR: define double* @ptr_scc_r2(double* %a, double* %b, double* returned %r)
;
; double* ptr_scc_r1(double* a, double* b, double* r);
; double* ptr_scc_r2(double* a, double* b, double* r);
@@ -237,41 +250,95 @@
}
-; TEST a singleton SCC with a lot of recursive calls
+; TEST a no-return singleton SCC
;
-; int* ret0(int *a) {
-; return *a ? a : ret0(ret0(ret0(...ret0(a)...)));
+; int* rt0(int *a) {
+; return *a ? a : rt0(a);
; }
;
-; FIXME: returned on %a missing:
-; CHECK: Function Attrs: noinline nounwind readonly uwtable
-; CHECK: define i32* @ret0(i32* readonly %a)
-define i32* @ret0(i32* %a) #0 {
+; FIXME: no-return missing
+; FNATTR: define i32* @rt0(i32* readonly %a)
+; BOTH: Function Attrs: noinline nounwind readonly uwtable
+; BOTH-NEXT: define i32* @rt0(i32* readonly returned %a)
+define i32* @rt0(i32* %a) #0 {
entry:
%v = load i32, i32* %a, align 4
%tobool = icmp ne i32 %v, 0
- %call = call i32* @ret0(i32* %a)
- %call1 = call i32* @ret0(i32* %call)
- %call2 = call i32* @ret0(i32* %call1)
- %call3 = call i32* @ret0(i32* %call2)
- %call4 = call i32* @ret0(i32* %call3)
- %call5 = call i32* @ret0(i32* %call4)
- %call6 = call i32* @ret0(i32* %call5)
- %call7 = call i32* @ret0(i32* %call6)
- %call8 = call i32* @ret0(i32* %call7)
- %call9 = call i32* @ret0(i32* %call8)
- %call10 = call i32* @ret0(i32* %call9)
- %call11 = call i32* @ret0(i32* %call10)
- %call12 = call i32* @ret0(i32* %call11)
- %call13 = call i32* @ret0(i32* %call12)
- %call14 = call i32* @ret0(i32* %call13)
- %call15 = call i32* @ret0(i32* %call14)
- %call16 = call i32* @ret0(i32* %call15)
- %call17 = call i32* @ret0(i32* %call16)
- %sel = select i1 %tobool, i32* %a, i32* %call17
+ %call = call i32* @rt0(i32* %a)
+ %sel = select i1 %tobool, i32* %a, i32* %call
+ ret i32* %sel
+}
+
+; TEST a no-return singleton SCC
+;
+; int* rt1(int *a) {
+; return *a ? undef : rt1(a);
+; }
+;
+; FIXME: no-return missing
+; FNATTR: define noalias i32* @rt1(i32* nocapture readonly %a)
+; BOTH: Function Attrs: noinline nounwind readonly uwtable
+; BOTH-NEXT: define noalias i32* @rt1(i32* nocapture readonly %a)
+define i32* @rt1(i32* %a) #0 {
+entry:
+ %v = load i32, i32* %a, align 4
+ %tobool = icmp ne i32 %v, 0
+ %call = call i32* @rt1(i32* %a)
+ %sel = select i1 %tobool, i32* undef, i32* %call
+ ret i32* %sel
+}
+
+; TEST another SCC test
+;
+; FNATTR: define i32* @rt2_helper(i32* %a)
+; FNATTR: define i32* @rt2(i32* readnone %a, i32* readnone %b)
+; BOTH: define i32* @rt2_helper(i32* %a)
+; BOTH: define i32* @rt2(i32* readnone %a, i32* readnone %b)
+define i32* @rt2_helper(i32* %a) #0 {
+entry:
+ %call = call i32* @rt2(i32* %a, i32* %a)
+ ret i32* %call
+}
+
+define i32* @rt2(i32* %a, i32 *%b) #0 {
+entry:
+ %cmp = icmp eq i32* %a, null
+ br i1 %cmp, label %if.then, label %if.end
+
+if.then:
+ %call = call i32* @rt2_helper(i32* %a)
+ br label %if.end
+
+if.end:
+ %sel = phi i32* [ %b, %entry], [%call, %if.then]
ret i32* %sel
}
+; TEST another SCC test
+;
+; FNATTR: define i32* @rt3_helper(i32* %a, i32* %b)
+; FNATTR: define i32* @rt3(i32* readnone %a, i32* readnone %b)
+; BOTH: define i32* @rt3_helper(i32* %a, i32* returned %b)
+; BOTH: define i32* @rt3(i32* readnone %a, i32* readnone returned %b)
+define i32* @rt3_helper(i32* %a, i32* %b) #0 {
+entry:
+ %call = call i32* @rt3(i32* %a, i32* %b)
+ ret i32* %call
+}
+
+define i32* @rt3(i32* %a, i32 *%b) #0 {
+entry:
+ %cmp = icmp eq i32* %a, null
+ br i1 %cmp, label %if.then, label %if.end
+
+if.then:
+ %call = call i32* @rt3_helper(i32* %a, i32* %b)
+ br label %if.end
+
+if.end:
+ %sel = phi i32* [ %b, %entry], [%call, %if.then]
+ ret i32* %sel
+}
; TEST address taken function with call to an external functions
;
@@ -282,11 +349,12 @@
; return r;
; }
;
-; CHECK: Function Attrs: noinline nounwind uwtable
-; CHECK: declare void @unknown_fn(i32* (i32*)*)
+; BOTH: declare void @unknown_fn(i32* (i32*)*)
;
-; CHECK: Function Attrs: noinline nounwind uwtable
-; CHECK: define i32* @calls_unknown_fn(i32* readnone returned %r)
+; BOTH: Function Attrs: noinline nounwind uwtable
+; BOTH-NEXT: define i32* @calls_unknown_fn(i32* readnone returned %r)
+; FNATTR: define i32* @calls_unknown_fn(i32* readnone returned %r)
+; ATTRIBUTOR: define i32* @calls_unknown_fn(i32* returned %r)
declare void @unknown_fn(i32* (i32*)*) #0
define i32* @calls_unknown_fn(i32* %r) #0 {
@@ -313,6 +381,12 @@
;
; CHECK: Function Attrs: noinline nounwind uwtable
; CHECK: define i32* @calls_maybe_redefined_fn(i32* returned %r)
+;
+; BOTH: Function Attrs: noinline nounwind uwtable
+; BOTH-NEXT: define linkonce_odr i32* @maybe_redefined_fn(i32* %r)
+;
+; BOTH: Function Attrs: noinline nounwind uwtable
+; BOTH-NEXT: define i32* @calls_maybe_redefined_fn(i32* returned %r)
define linkonce_odr i32* @maybe_redefined_fn(i32* %r) #0 {
entry:
ret i32* %r
@@ -324,6 +398,36 @@
ret i32* %r
}
+; TEST return call to a function that might be redifined at link time
+;
+; int *maybe_redefined_fn2(int *r) {
+; return r;
+; }
+;
+; int *calls_maybe_redefined_fn2(int *r) {
+; return maybe_redefined_fn2(r);
+; }
+;
+; Verify the maybe-redefined function is not annotated:
+;
+; BOTH: Function Attrs: noinline nounwind uwtable
+; BOTH-NEXT: define linkonce_odr i32* @maybe_redefined_fn2(i32* %r)
+; BOTH: Function Attrs: noinline nounwind uwtable
+; BOTH-NEXT: define i32* @calls_maybe_redefined_fn2(i32* %r)
+;
+; FNATTR: define i32* @calls_maybe_redefined_fn2(i32* %r)
+; ATTRIBUTOR: define i32* @calls_maybe_redefined_fn2(i32* %r)
+define linkonce_odr i32* @maybe_redefined_fn2(i32* %r) #0 {
+entry:
+ ret i32* %r
+}
+
+define i32* @calls_maybe_redefined_fn2(i32* %r) #0 {
+entry:
+ %call = call i32* @maybe_redefined_fn2(i32* %r)
+ ret i32* %call
+}
+
; TEST returned argument goes through select and phi
;
@@ -334,9 +438,11 @@
; return b == 0? b : x;
; }
;
-; FIXME: returned on %b missing:
-; CHECK: Function Attrs: noinline norecurse nounwind readnone uwtable
-; CHECK: define double @select_and_phi(double %b)
+; BOTH: Function Attrs: noinline norecurse nounwind readnone uwtable
+; BOTH-NEXT: define double @select_and_phi(double returned %b)
+;
+; FNATTR: define double @select_and_phi(double %b)
+; ATTRIBUTOR: define double @select_and_phi(double returned %b)
define double @select_and_phi(double %b) #0 {
entry:
%cmp = fcmp ogt double %b, 0.000000e+00
@@ -362,9 +468,11 @@
; return b == 0? b : x;
; }
;
-; FIXME: returned on %b missing:
-; CHECK: Function Attrs: noinline nounwind readnone uwtable
-; CHECK: define double @recursion_select_and_phi(i32 %a, double %b)
+; BOTH: Function Attrs: noinline nounwind readnone uwtable
+; BOTH-NEXT: define double @recursion_select_and_phi(i32 %a, double returned %b)
+;
+; FNATTR: define double @recursion_select_and_phi(i32 %a, double %b)
+; ATTRIBUTOR: define double @recursion_select_and_phi(i32 %a, double returned %b)
define double @recursion_select_and_phi(i32 %a, double %b) #0 {
entry:
%dec = add nsw i32 %a, -1
@@ -389,9 +497,11 @@
; return (double*)b;
; }
;
-; FIXME: returned on %b missing:
-; CHECK: Function Attrs: noinline norecurse nounwind readnone uwtable
-; CHECK: define double* @bitcast(i32* readnone %b)
+; BOTH: Function Attrs: noinline norecurse nounwind readnone uwtable
+; BOTH-NEXT: define double* @bitcast(i32* readnone returned %b)
+;
+; FNATTR: define double* @bitcast(i32* readnone %b)
+; ATTRIBUTOR: define double* @bitcast(i32* returned %b)
define double* @bitcast(i32* %b) #0 {
entry:
%bc0 = bitcast i32* %b to double*
@@ -408,9 +518,11 @@
; return b != 0 ? b : x;
; }
;
-; FIXME: returned on %b missing:
-; CHECK: Function Attrs: noinline norecurse nounwind readnone uwtable
-; CHECK: define double* @bitcasts_select_and_phi(i32* readnone %b)
+; BOTH: Function Attrs: noinline norecurse nounwind readnone uwtable
+; BOTH-NEXT: define double* @bitcasts_select_and_phi(i32* readnone returned %b)
+;
+; FNATTR: define double* @bitcasts_select_and_phi(i32* readnone %b)
+; ATTRIBUTOR: define double* @bitcasts_select_and_phi(i32* returned %b)
define double* @bitcasts_select_and_phi(i32* %b) #0 {
entry:
%bc0 = bitcast i32* %b to double*
@@ -442,8 +554,11 @@
; /* return undef */
; }
;
-; CHECK: Function Attrs: noinline norecurse nounwind readnone uwtable
-; CHECK: define double* @ret_arg_arg_undef(i32* readnone %b)
+; BOTH: Function Attrs: noinline norecurse nounwind readnone uwtable
+; BOTH-NEXT: define double* @ret_arg_arg_undef(i32* readnone returned %b)
+;
+; FNATTR: define double* @ret_arg_arg_undef(i32* readnone %b)
+; ATTRIBUTOR: define double* @ret_arg_arg_undef(i32* returned %b)
define double* @ret_arg_arg_undef(i32* %b) #0 {
entry:
%bc0 = bitcast i32* %b to double*
@@ -475,8 +590,11 @@
; /* return undef */
; }
;
-; CHECK: Function Attrs: noinline norecurse nounwind readnone uwtable
-; CHECK: define double* @ret_undef_arg_arg(i32* readnone %b)
+; BOTH: Function Attrs: noinline norecurse nounwind readnone uwtable
+; BOTH-NEXT: define double* @ret_undef_arg_arg(i32* readnone returned %b)
+;
+; FNATTR: define double* @ret_undef_arg_arg(i32* readnone %b)
+; ATTRIBUTOR: define double* @ret_undef_arg_arg(i32* returned %b)
define double* @ret_undef_arg_arg(i32* %b) #0 {
entry:
%bc0 = bitcast i32* %b to double*
@@ -508,8 +626,11 @@
; /* return undef */
; }
;
-; CHECK: Function Attrs: noinline norecurse nounwind readnone uwtable
-; CHECK: define double* @ret_undef_arg_undef(i32* readnone %b)
+; BOTH: Function Attrs: noinline norecurse nounwind readnone uwtable
+; BOTH-NEXT: define double* @ret_undef_arg_undef(i32* readnone returned %b)
+;
+; FNATTR: define double* @ret_undef_arg_undef(i32* readnone %b)
+; ATTRIBUTOR: define double* @ret_undef_arg_undef(i32* returned %b)
define double* @ret_undef_arg_undef(i32* %b) #0 {
entry:
%bc0 = bitcast i32* %b to double*
@@ -534,13 +655,17 @@
; int* ret_arg_or_unknown(int* b) {
; if (b == 0)
; return b;
-; return unknown(b);
+; return unknown();
; }
;
-; Verify we do not assume b is returned>
+; Verify we do not assume b is returned
;
-; CHECK: define i32* @ret_arg_or_unknown(i32* %b)
-; CHECK: define i32* @ret_arg_or_unknown_through_phi(i32* %b)
+; FNATTR: define i32* @ret_arg_or_unknown(i32* %b)
+; FNATTR: define i32* @ret_arg_or_unknown_through_phi(i32* %b)
+; ATTRIBUTOR: define i32* @ret_arg_or_unknown(i32* %b)
+; ATTRIBUTOR: define i32* @ret_arg_or_unknown_through_phi(i32* %b)
+; BOTH: define i32* @ret_arg_or_unknown(i32* %b)
+; BOTH: define i32* @ret_arg_or_unknown_through_phi(i32* %b)
declare i32* @unknown(i32*)
define i32* @ret_arg_or_unknown(i32* %b) #0 {
@@ -573,11 +698,40 @@
ret i32* %phi
}
+; TEST inconsistent IR in dead code.
+;
+; FNATTR: define i32 @deadblockcall1(i32 %A)
+; FNATTR: define i32 @deadblockcall2(i32 %A)
+; ATTRIBUTOR: define i32 @deadblockcall1(i32 returned %A)
+; ATTRIBUTOR: define i32 @deadblockcall2(i32 returned %A)
+; BOTH: define i32 @deadblockcall1(i32 returned %A)
+; BOTH: define i32 @deadblockcall2(i32 returned %A)
+define i32 @deadblockcall1(i32 %A) #0 {
+entry:
+ ret i32 %A
+unreachableblock:
+ %B = call i32 @deadblockcall1(i32 %B)
+ ret i32 %B
+}
+
+declare i32 @deadblockcall_helper(i32 returned %A);
+
+define i32 @deadblockcall2(i32 %A) #0 {
+entry:
+ ret i32 %A
+unreachableblock1:
+ %B = call i32 @deadblockcall_helper(i32 %B)
+ ret i32 %B
+unreachableblock2:
+ %C = call i32 @deadblockcall1(i32 %C)
+ ret i32 %C
+}
+
attributes #0 = { noinline nounwind uwtable }
-; CHECK-NOT: attributes #
-; CHECK-DAG: attributes #{{[0-9]*}} = { noinline norecurse nounwind readnone uwtable }
-; CHECK-DAG: attributes #{{[0-9]*}} = { noinline nounwind readnone uwtable }
-; CHECK-DAG: attributes #{{[0-9]*}} = { noinline nounwind readonly uwtable }
-; CHECK-DAG: attributes #{{[0-9]*}} = { noinline nounwind uwtable }
-; CHECK-NOT: attributes #
+; BOTH-NOT: attributes #
+; BOTH-DAG: attributes #{{[0-9]*}} = { noinline norecurse nounwind readnone uwtable }
+; BOTH-DAG: attributes #{{[0-9]*}} = { noinline nounwind readnone uwtable }
+; BOTH-DAG: attributes #{{[0-9]*}} = { noinline nounwind readonly uwtable }
+; BOTH-DAG: attributes #{{[0-9]*}} = { noinline nounwind uwtable }
+; BOTH-NOT: attributes #
Index: llvm/trunk/test/Transforms/FunctionAttrs/read_write_returned_arguments_scc.ll
===================================================================
--- llvm/trunk/test/Transforms/FunctionAttrs/read_write_returned_arguments_scc.ll
+++ llvm/trunk/test/Transforms/FunctionAttrs/read_write_returned_arguments_scc.ll
@@ -31,7 +31,7 @@
target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
; CHECK: Function Attrs: nofree nounwind
-; CHECK-NEXT: define i32* @external_ret2_nrw(i32* %n0, i32* %r0, i32* %w0)
+; CHECK-NEXT: define i32* @external_ret2_nrw(i32* %n0, i32* %r0, i32* returned %w0)
define i32* @external_ret2_nrw(i32* %n0, i32* %r0, i32* %w0) {
entry:
%call = call i32* @internal_ret0_nw(i32* %n0, i32* %w0)
@@ -42,7 +42,7 @@
}
; CHECK: Function Attrs: nofree nounwind
-; CHECK-NEXT: define internal i32* @internal_ret0_nw(i32* %n0, i32* %w0)
+; CHECK-NEXT: define internal i32* @internal_ret0_nw(i32* returned %n0, i32* %w0)
define internal i32* @internal_ret0_nw(i32* %n0, i32* %w0) {
entry:
%r0 = alloca i32, align 4
@@ -71,7 +71,7 @@
}
; CHECK: Function Attrs: nofree nounwind
-; CHECK-NEXT: define internal i32* @internal_ret1_rrw(i32* %r0, i32* %r1, i32* %w0)
+; CHECK-NEXT: define internal i32* @internal_ret1_rrw(i32* %r0, i32* returned %r1, i32* %w0)
define internal i32* @internal_ret1_rrw(i32* %r0, i32* %r1, i32* %w0) {
entry:
%0 = load i32, i32* %r0, align 4
@@ -122,7 +122,7 @@
}
; CHECK: Function Attrs: nofree nounwind
-; CHECK-NEXT: define internal i32* @internal_ret1_rw(i32* %r0, i32* %w0)
+; CHECK-NEXT: define internal i32* @internal_ret1_rw(i32* %r0, i32* returned %w0)
define internal i32* @internal_ret1_rw(i32* %r0, i32* %w0) {
entry:
%0 = load i32, i32* %r0, align 4
@@ -148,7 +148,7 @@
}
; CHECK: Function Attrs: nofree nounwind
-; CHECK-NEXT: define i32* @external_source_ret2_nrw(i32* %n0, i32* %r0, i32* %w0)
+; CHECK-NEXT: define i32* @external_source_ret2_nrw(i32* %n0, i32* %r0, i32* returned %w0)
define i32* @external_source_ret2_nrw(i32* %n0, i32* %r0, i32* %w0) {
entry:
%call = call i32* @external_sink_ret2_nrw(i32* %n0, i32* %r0, i32* %w0)
Index: llvm/trunk/lib/Transforms/IPO/Attributor.cpp
===================================================================
--- llvm/trunk/lib/Transforms/IPO/Attributor.cpp
+++ llvm/trunk/lib/Transforms/IPO/Attributor.cpp
@@ -44,6 +44,11 @@
"Number of abstract attributes manifested in IR");
STATISTIC(NumFnNoUnwind, "Number of functions marked nounwind");
+STATISTIC(NumFnUniqueReturned, "Number of function with unique return");
+STATISTIC(NumFnKnownReturns, "Number of function with known return values");
+STATISTIC(NumFnArgumentReturned,
+ "Number of function arguments marked returned");
+
// TODO: Determine a good default value.
//
// In the LLVM-TS and SPEC2006, 32 seems to not induce compile time overheads
@@ -91,11 +96,97 @@
case Attribute::NoUnwind:
NumFnNoUnwind++;
return;
+ case Attribute::Returned:
+ NumFnArgumentReturned++;
+ return;
default:
return;
}
}
+template <typename StateTy>
+using followValueCB_t = std::function<bool(Value *, StateTy &State)>;
+template <typename StateTy>
+using visitValueCB_t = std::function<void(Value *, StateTy &State)>;
+
+/// Recursively visit all values that might become \p InitV at some point. This
+/// will be done by looking through cast instructions, selects, phis, and calls
+/// with the "returned" attribute. The callback \p FollowValueCB is asked before
+/// a potential origin value is looked at. If no \p FollowValueCB is passed, a
+/// default one is used that will make sure we visit every value only once. Once
+/// we cannot look through the value any further, the callback \p VisitValueCB
+/// is invoked and passed the current value and the \p State. To limit how much
+/// effort is invested, we will never visit more than \p MaxValues values.
+template <typename StateTy>
+static bool genericValueTraversal(
+ Value *InitV, StateTy &State, visitValueCB_t<StateTy> &VisitValueCB,
+ followValueCB_t<StateTy> *FollowValueCB = nullptr, int MaxValues = 8) {
+
+ SmallPtrSet<Value *, 16> Visited;
+ followValueCB_t<bool> DefaultFollowValueCB = [&](Value *Val, bool &) {
+ return Visited.insert(Val).second;
+ };
+
+ if (!FollowValueCB)
+ FollowValueCB = &DefaultFollowValueCB;
+
+ SmallVector<Value *, 16> Worklist;
+ Worklist.push_back(InitV);
+
+ int Iteration = 0;
+ do {
+ Value *V = Worklist.pop_back_val();
+
+ // Check if we should process the current value. To prevent endless
+ // recursion keep a record of the values we followed!
+ if (!(*FollowValueCB)(V, State))
+ continue;
+
+ // Make sure we limit the compile time for complex expressions.
+ if (Iteration++ >= MaxValues)
+ return false;
+
+ // Explicitly look through calls with a "returned" attribute if we do
+ // not have a pointer as stripPointerCasts only works on them.
+ if (V->getType()->isPointerTy()) {
+ V = V->stripPointerCasts();
+ } else {
+ CallSite CS(V);
+ if (CS && CS.getCalledFunction()) {
+ Value *NewV = nullptr;
+ for (Argument &Arg : CS.getCalledFunction()->args())
+ if (Arg.hasReturnedAttr()) {
+ NewV = CS.getArgOperand(Arg.getArgNo());
+ break;
+ }
+ if (NewV) {
+ Worklist.push_back(NewV);
+ continue;
+ }
+ }
+ }
+
+ // Look through select instructions, visit both potential values.
+ if (auto *SI = dyn_cast<SelectInst>(V)) {
+ Worklist.push_back(SI->getTrueValue());
+ Worklist.push_back(SI->getFalseValue());
+ continue;
+ }
+
+ // Look through phi nodes, visit all operands.
+ if (auto *PHI = dyn_cast<PHINode>(V)) {
+ Worklist.append(PHI->op_begin(), PHI->op_end());
+ continue;
+ }
+
+ // Once a leaf is reached we inform the user through the callback.
+ VisitValueCB(V, State);
+ } while (!Worklist.empty());
+
+ // All values have been visited.
+ return true;
+}
+
/// Helper to identify the correct offset into an attribute list.
static unsigned getAttrIndex(AbstractAttribute::ManifestPosition MP,
unsigned ArgNo = 0) {
@@ -303,6 +394,331 @@
return ChangeStatus::UNCHANGED;
}
+/// --------------------- Function Return Values -------------------------------
+
+/// "Attribute" that collects all potential returned values and the return
+/// instructions that they arise from.
+///
+/// If there is a unique returned value R, the manifest method will:
+/// - mark R with the "returned" attribute, if R is an argument.
+class AAReturnedValuesImpl final : public AAReturnedValues, AbstractState {
+
+ /// Mapping of values potentially returned by the associated function to the
+ /// return instructions that might return them.
+ DenseMap<Value *, SmallPtrSet<ReturnInst *, 2>> ReturnedValues;
+
+ /// State flags
+ ///
+ ///{
+ bool IsFixed;
+ bool IsValidState;
+ bool HasOverdefinedReturnedCalls;
+ ///}
+
+ /// Collect values that could become \p V in the set \p Values, each mapped to
+ /// \p ReturnInsts.
+ void collectValuesRecursively(
+ Attributor &A, Value *V, SmallPtrSetImpl<ReturnInst *> &ReturnInsts,
+ DenseMap<Value *, SmallPtrSet<ReturnInst *, 2>> &Values) {
+
+ visitValueCB_t<bool> VisitValueCB = [&](Value *Val, bool &) {
+ assert(!isa<Instruction>(Val) ||
+ &getAnchorScope() == cast<Instruction>(Val)->getFunction());
+ Values[Val].insert(ReturnInsts.begin(), ReturnInsts.end());
+ };
+
+ bool UnusedBool;
+ bool Success = genericValueTraversal(V, UnusedBool, VisitValueCB);
+
+ // If we did abort the above traversal we haven't see all the values.
+ // Consequently, we cannot know if the information we would derive is
+ // accurate so we give up early.
+ if (!Success)
+ indicatePessimisticFixpoint();
+ }
+
+public:
+ /// See AbstractAttribute::AbstractAttribute(...).
+ AAReturnedValuesImpl(Function &F, InformationCache &InfoCache)
+ : AAReturnedValues(F, InfoCache) {
+ // We do not have an associated argument yet.
+ AssociatedVal = nullptr;
+ }
+
+ /// See AbstractAttribute::initialize(...).
+ void initialize(Attributor &A) override {
+ // Reset the state.
+ AssociatedVal = nullptr;
+ IsFixed = false;
+ IsValidState = true;
+ HasOverdefinedReturnedCalls = false;
+ ReturnedValues.clear();
+
+ Function &F = cast<Function>(getAnchoredValue());
+
+ // The map from instruction opcodes to those instructions in the function.
+ auto &OpcodeInstMap = InfoCache.getOpcodeInstMapForFunction(F);
+
+ // Look through all arguments, if one is marked as returned we are done.
+ for (Argument &Arg : F.args()) {
+ if (Arg.hasReturnedAttr()) {
+
+ auto &ReturnInstSet = ReturnedValues[&Arg];
+ for (Instruction *RI : OpcodeInstMap[Instruction::Ret])
+ ReturnInstSet.insert(cast<ReturnInst>(RI));
+
+ indicateOptimisticFixpoint();
+ return;
+ }
+ }
+
+ // If no argument was marked as returned we look at all return instructions
+ // and collect potentially returned values.
+ for (Instruction *RI : OpcodeInstMap[Instruction::Ret]) {
+ SmallPtrSet<ReturnInst *, 1> RISet({cast<ReturnInst>(RI)});
+ collectValuesRecursively(A, cast<ReturnInst>(RI)->getReturnValue(), RISet,
+ ReturnedValues);
+ }
+ }
+
+ /// See AbstractAttribute::manifest(...).
+ virtual ChangeStatus manifest(Attributor &A) override;
+
+ /// See AbstractAttribute::getState(...).
+ virtual AbstractState &getState() override { return *this; }
+
+ /// See AbstractAttribute::getState(...).
+ virtual const AbstractState &getState() const override { return *this; }
+
+ /// See AbstractAttribute::getManifestPosition().
+ virtual ManifestPosition getManifestPosition() const override {
+ return MP_ARGUMENT;
+ }
+
+ /// See AbstractAttribute::updateImpl(Attributor &A).
+ virtual ChangeStatus updateImpl(Attributor &A) override;
+
+ /// Return the number of potential return values, -1 if unknown.
+ size_t getNumReturnValues() const {
+ return isValidState() ? ReturnedValues.size() : -1;
+ }
+
+ /// Return an assumed unique return value if a single candidate is found. If
+ /// there cannot be one, return a nullptr. If it is not clear yet, return the
+ /// Optional::NoneType.
+ Optional<Value *> getAssumedUniqueReturnValue() const;
+
+ /// See AbstractState::checkForallReturnedValues(...).
+ virtual bool
+ checkForallReturnedValues(std::function<bool(Value &)> &Pred) const override;
+
+ /// Pretty print the attribute similar to the IR representation.
+ virtual const std::string getAsStr() const override;
+
+ /// See AbstractState::isAtFixpoint().
+ bool isAtFixpoint() const override { return IsFixed; }
+
+ /// See AbstractState::isValidState().
+ bool isValidState() const override { return IsValidState; }
+
+ /// See AbstractState::indicateOptimisticFixpoint(...).
+ void indicateOptimisticFixpoint() override {
+ IsFixed = true;
+ IsValidState &= true;
+ }
+ void indicatePessimisticFixpoint() override {
+ IsFixed = true;
+ IsValidState = false;
+ }
+};
+
+ChangeStatus AAReturnedValuesImpl::manifest(Attributor &A) {
+ ChangeStatus Changed = ChangeStatus::UNCHANGED;
+
+ // Bookkeeping.
+ assert(isValidState());
+ NumFnKnownReturns++;
+
+ // Check if we have an assumed unique return value that we could manifest.
+ Optional<Value *> UniqueRV = getAssumedUniqueReturnValue();
+
+ if (!UniqueRV.hasValue() || !UniqueRV.getValue())
+ return Changed;
+
+ // Bookkeeping.
+ NumFnUniqueReturned++;
+
+ // If the assumed unique return value is an argument, annotate it.
+ if (auto *UniqueRVArg = dyn_cast<Argument>(UniqueRV.getValue())) {
+ AssociatedVal = UniqueRVArg;
+ Changed = AbstractAttribute::manifest(A) | Changed;
+ }
+
+ return Changed;
+}
+
+const std::string AAReturnedValuesImpl::getAsStr() const {
+ return (isAtFixpoint() ? "returns(#" : "may-return(#") +
+ (isValidState() ? std::to_string(getNumReturnValues()) : "?") + ")";
+}
+
+Optional<Value *> AAReturnedValuesImpl::getAssumedUniqueReturnValue() const {
+ // If checkForallReturnedValues provides a unique value, ignoring potential
+ // undef values that can also be present, it is assumed to be the actual
+ // return value and forwarded to the caller of this method. If there are
+ // multiple, a nullptr is returned indicating there cannot be a unique
+ // returned value.
+ Optional<Value *> UniqueRV;
+
+ std::function<bool(Value &)> Pred = [&](Value &RV) -> bool {
+ // If we found a second returned value and neither the current nor the saved
+ // one is an undef, there is no unique returned value. Undefs are special
+ // since we can pretend they have any value.
+ if (UniqueRV.hasValue() && UniqueRV != &RV &&
+ !(isa<UndefValue>(RV) || isa<UndefValue>(UniqueRV.getValue()))) {
+ UniqueRV = nullptr;
+ return false;
+ }
+
+ // Do not overwrite a value with an undef.
+ if (!UniqueRV.hasValue() || !isa<UndefValue>(RV))
+ UniqueRV = &RV;
+
+ return true;
+ };
+
+ if (!checkForallReturnedValues(Pred))
+ UniqueRV = nullptr;
+
+ return UniqueRV;
+}
+
+bool AAReturnedValuesImpl::checkForallReturnedValues(
+ std::function<bool(Value &)> &Pred) const {
+ if (!isValidState())
+ return false;
+
+ // Check all returned values but ignore call sites as long as we have not
+ // encountered an overdefined one during an update.
+ for (auto &It : ReturnedValues) {
+ Value *RV = It.first;
+
+ ImmutableCallSite ICS(RV);
+ if (ICS && !HasOverdefinedReturnedCalls)
+ continue;
+
+ if (!Pred(*RV))
+ return false;
+ }
+
+ return true;
+}
+
+ChangeStatus AAReturnedValuesImpl::updateImpl(Attributor &A) {
+
+ // Check if we know of any values returned by the associated function,
+ // if not, we are done.
+ if (getNumReturnValues() == 0) {
+ indicateOptimisticFixpoint();
+ return ChangeStatus::UNCHANGED;
+ }
+
+ // Check if any of the returned values is a call site we can refine.
+ decltype(ReturnedValues) AddRVs;
+ bool HasCallSite = false;
+
+ // Look at all returned call sites.
+ for (auto &It : ReturnedValues) {
+ SmallPtrSet<ReturnInst *, 2> &ReturnInsts = It.second;
+ Value *RV = It.first;
+ LLVM_DEBUG(dbgs() << "[AAReturnedValues] Potentially returned value " << *RV
+ << "\n");
+
+ // Only call sites can change during an update, ignore the rest.
+ CallSite RetCS(RV);
+ if (!RetCS)
+ continue;
+
+ // For now, any call site we see will prevent us from directly fixing the
+ // state. However, if the information on the callees is fixed, the call
+ // sites will be removed and we will fix the information for this state.
+ HasCallSite = true;
+
+ // Try to find a assumed unique return value for the called function.
+ auto *RetCSAA = A.getAAFor<AAReturnedValuesImpl>(*this, *RV);
+ if (!RetCSAA || !RetCSAA->isValidState()) {
+ HasOverdefinedReturnedCalls = true;
+ LLVM_DEBUG(dbgs() << "[AAReturnedValues] Returned call site (" << *RV
+ << ") with " << (RetCSAA ? "invalid" : "no")
+ << " associated state\n");
+ continue;
+ }
+
+ // Try to find a assumed unique return value for the called function.
+ Optional<Value *> AssumedUniqueRV = RetCSAA->getAssumedUniqueReturnValue();
+
+ // If no assumed unique return value was found due to the lack of
+ // candidates, we may need to resolve more calls (through more update
+ // iterations) or the called function will not return. Either way, we simply
+ // stick with the call sites as return values. Because there were not
+ // multiple possibilities, we do not treat it as overdefined.
+ if (!AssumedUniqueRV.hasValue())
+ continue;
+
+ // If multiple, non-refinable values were found, there cannot be a unique
+ // return value for the called function. The returned call is overdefined!
+ if (!AssumedUniqueRV.getValue()) {
+ HasOverdefinedReturnedCalls = true;
+ LLVM_DEBUG(dbgs() << "[AAReturnedValues] Returned call site has multiple "
+ "potentially returned values\n");
+ continue;
+ }
+
+ LLVM_DEBUG({
+ bool UniqueRVIsKnown = RetCSAA->isAtFixpoint();
+ dbgs() << "[AAReturnedValues] Returned call site "
+ << (UniqueRVIsKnown ? "known" : "assumed")
+ << " unique return value: " << *AssumedUniqueRV << "\n";
+ });
+
+ // The assumed unique return value.
+ Value *AssumedRetVal = AssumedUniqueRV.getValue();
+
+ // If the assumed unique return value is an argument, lookup the matching
+ // call site operand and recursively collect new returned values.
+ // If it is not an argument, it is just put into the set of returned values
+ // as we would have already looked through casts, phis, and similar values.
+ if (Argument *AssumedRetArg = dyn_cast<Argument>(AssumedRetVal))
+ collectValuesRecursively(A,
+ RetCS.getArgOperand(AssumedRetArg->getArgNo()),
+ ReturnInsts, AddRVs);
+ else
+ AddRVs[AssumedRetVal].insert(ReturnInsts.begin(), ReturnInsts.end());
+ }
+
+ // Keep track of any change to trigger updates on dependent attributes.
+ ChangeStatus Changed = ChangeStatus::UNCHANGED;
+
+ for (auto &It : AddRVs) {
+ assert(!It.second.empty() && "Entry does not add anything.");
+ auto &ReturnInsts = ReturnedValues[It.first];
+ for (ReturnInst *RI : It.second)
+ if (ReturnInsts.insert(RI).second) {
+ LLVM_DEBUG(dbgs() << "[AAReturnedValues] Add new returned value "
+ << *It.first << " => " << *RI << "\n");
+ Changed = ChangeStatus::CHANGED;
+ }
+ }
+
+ // If there is no call site in the returned values we are done.
+ if (!HasCallSite) {
+ indicateOptimisticFixpoint();
+ return ChangeStatus::CHANGED;
+ }
+
+ return Changed;
+}
+
/// ----------------------------------------------------------------------------
/// Attributor
/// ----------------------------------------------------------------------------
@@ -448,6 +864,15 @@
// Every function can be nounwind.
registerAA(*new AANoUnwindFunction(F, InfoCache));
+ // Return attributes are only appropriate if the return type is non void.
+ Type *ReturnType = F.getReturnType();
+ if (!ReturnType->isVoidTy()) {
+ // Argument attribute "returned" --- Create only one per function even
+ // though it is an argument attribute.
+ if (!Whitelist || Whitelist->count(AAReturnedValues::ID))
+ registerAA(*new AAReturnedValuesImpl(F, InfoCache));
+ }
+
// Walk all instructions to find more attribute opportunities and also
// interesting instructions that might be queried by abstract attributes
// during their initialization or update.
@@ -474,6 +899,7 @@
case Instruction::CleanupRet:
case Instruction::CatchSwitch:
case Instruction::Resume:
+ case Instruction::Ret:
IsInterestingOpcode = true;
}
if (IsInterestingOpcode)
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