maxjhandsome
/
llvm-project
forked from OSchip/llvm-project
1
0
Fork 0
Code Issues Pull Requests Packages Releases Wiki Activity

[PowerPC] Fix missing nop after call to weak callee. 

Weak functions can be replaced by other functions at link time. Previously it
was assumed that no matter what the weak callee function was replaced with it
would still share the same TOC as the caller. This is no longer true as a weak
callee with a TOC setup can be replaced by another function that was compiled
with PC Relative and does not have a TOC at all.

This patch makes sure that all calls to functions defined as weak from a caller
that has a valid TOC have a nop after the call to allow a place for the linker
to restore the TOC.

Reviewed By: NeHuang

Differential Revision: https://reviews.llvm.org/D91983
This commit is contained in:
Stefan Pintilie 2020-12-08 08:57:37 -06:00
parent 45878ede7e
commit 2812c15156
7 changed files with 31 additions and 33 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

13
llvm/lib/Target/PowerPC/PPCISelLowering.cpp
View File

@ -4799,6 +4799,13 @@ static bool callsShareTOCBase(const Function *Caller, SDValue Callee,
if (STICallee->isUsingPCRelativeCalls())
return false;
// If the GV is not a strong definition then we need to assume it can be
// replaced by another function at link time. The function that replaces
// it may not share the same TOC as the caller since the callee may be
// replaced by a PC Relative version of the same function.
if (!GV->isStrongDefinitionForLinker())
return false;
// The medium and large code models are expected to provide a sufficiently
// large TOC to provide all data addressing needs of a module with a
// single TOC.
@ -4806,12 +4813,6 @@ static bool callsShareTOCBase(const Function *Caller, SDValue Callee,
CodeModel::Large == TM.getCodeModel())
return true;
// Otherwise we need to ensure callee and caller are in the same section,
// since the linker may allocate multiple TOCs, and we don't know which
// sections will belong to the same TOC base.
if (!GV->isStrongDefinitionForLinker())
return false;
// Any explicitly-specified sections and section prefixes must also match.
// Also, if we're using -ffunction-sections, then each function is always in
// a different section (the same is true for COMDAT functions).

8
llvm/test/CodeGen/PowerPC/ppc64-blnop.ll
View File

@ -76,7 +76,7 @@ define void @wo_hcaller(%class.T* %this, i8* %c) {
; CHECK-LABEL: wo_hcaller:
; CHECK: bl wo_hcallee
; CHECK-NOT: nop
; CHECK-NEXT: nop
; SCM-LABEL: wo_hcaller:
; SCM: bl wo_hcallee
@ -90,7 +90,7 @@ define void @wo_pcaller(%class.T* %this, i8* %c) {
; CHECK-LABEL: wo_pcaller:
; CHECK: bl wo_pcallee
; CHECK-NOT: nop
; CHECK-NEXT: nop
; SCM-LABEL: wo_pcaller:
; SCM: bl wo_pcallee
@ -114,7 +114,7 @@ define void @w_pcaller(i8* %ptr) {
; CHECK-LABEL: w_pcaller:
; CHECK: bl w_pcallee
; CHECK-NOT: nop
; CHECK-NEXT: nop
; SCM-LABEL: w_pcaller:
; SCM: bl w_pcallee
@ -128,7 +128,7 @@ define void @w_hcaller(i8* %ptr) {
; CHECK-LABEL: w_hcaller:
; CHECK: bl w_hcallee
; CHECK-NOT: nop
; CHECK-NEXT: nop
; SCM-LABEL: w_hcaller:
; SCM: bl w_hcallee

12
llvm/test/CodeGen/PowerPC/ppc64-calls.ll
View File

@ -23,18 +23,14 @@ define void @test_direct() nounwind readnone {
ret void
}
; Calls to weak function requires a TOC restore 'nop' with the small codemodel
; Calls to weak function requires a TOC restore 'nop' with all code models
; because the definition that gets choosen at link time may come from a
; different section even though we have seen a weak definition in the same
; section at compile time.
; With large and medium codemodels no TOC restore is needed, since we know
; whichever definition is choosen it resides within the same DSO boundaries and
; therefore shares the same TOC.
; different compilation unit that was compiled with PC Relative and has no TOC.
define void @test_weak() nounwind readnone {
tail call void @foo_weak() nounwind
; CHECK-LABEL: test_weak:
; CHECK: b foo_weak
; CHECK-NOT: nop
; CHECK: bl foo_weak
; CHECK-NEXT: nop
; SCM-LABEL: test_weak:
; SCM: bl foo_weak

12
llvm/test/CodeGen/PowerPC/ppc64-sibcall.ll
View File

@ -135,7 +135,7 @@ define void @wo_hcaller(%class.T* %this, i8* %c) {
ret void
; CHECK-SCO-LABEL: wo_hcaller:
; CHECK-SCO: b wo_hcallee
; CHECK-SCO: bl wo_hcallee
; SCM-LABEL: wo_hcaller:
; SCM: bl wo_hcallee
@ -147,7 +147,7 @@ define void @wo_pcaller(%class.T* %this, i8* %c) {
ret void
; CHECK-SCO-LABEL: wo_pcaller:
; CHECK-SCO: b wo_pcallee
; CHECK-SCO: bl wo_pcallee
; SCM-LABEL: wo_pcaller:
; SCM: bl wo_pcallee
@ -159,7 +159,7 @@ define void @wo_caller(%class.T* %this, i8* %c) {
ret void
; CHECK-SCO-LABEL: wo_caller:
; CHECK-SCO: b wo_callee
; CHECK-SCO: bl wo_callee
; SCM-LABEL: wo_caller:
; SCM: bl wo_callee
@ -171,7 +171,7 @@ define void @w_pcaller(i8* %ptr) {
ret void
; CHECK-SCO-LABEL: w_pcaller:
; CHECK-SCO: b w_pcallee
; CHECK-SCO: bl w_pcallee
; SCM-LABEL: w_pcaller:
; SCM: bl w_pcallee
@ -183,7 +183,7 @@ define void @w_hcaller(i8* %ptr) {
ret void
; CHECK-SCO-LABEL: w_hcaller:
; CHECK-SCO: b w_hcallee
; CHECK-SCO: bl w_hcallee
; SCM-LABEL: w_hcaller:
; SCM: bl w_hcallee
@ -195,7 +195,7 @@ define void @w_caller(i8* %ptr) {
ret void
; CHECK-SCO-LABEL: w_caller:
; CHECK-SCO: b w_callee
; CHECK-SCO: bl w_callee
; SCM-LABEL: w_caller:
; SCM: bl w_callee

1
llvm/test/CodeGen/PowerPC/pr41088.ll
View File

@ -54,6 +54,7 @@ define void @test(%6* %arg, %7* %arg1, %12* %arg2) unnamed_addr personality i32
; CHECK-NEXT: # %bb.2: # %bb12
; CHECK-NEXT: clrldi r4, r3, 32
; CHECK-NEXT: bl test3
; CHECK-NEXT: nop
; CHECK-NEXT: addi r1, r1, 32
; CHECK-NEXT: ld r0, 16(r1)
; CHECK-NEXT: mtlr r0

12
llvm/test/CodeGen/PowerPC/preemption.ll
View File

@ -170,7 +170,7 @@ define signext i32 @weak_default_function_caller(i32 %i) {
; STATIC-LABEL: @weak_default_function_caller
; STATIC: bl weak_default_function
; STATIC-NOT: nop
; STATIC-NEXT: nop
; STATIC: blr
; CHECK-LABEL: @weak_default_function_caller
@ -223,12 +223,12 @@ define signext i32 @weak_local_function_caller(i32 %i) {
; STATIC-LABEL: @weak_local_function_caller
; STATIC: bl weak_local_function
; STATIC-NOT: nop
; STATIC-NEXT: nop
; STATIC: blr
; CHECK-LABEL: @weak_local_function_caller
; CHECK: bl weak_local_function
; CHECK-NOT: nop
; CHECK-NEXT: nop
; CHECK: blr
}
@ -239,12 +239,12 @@ define i32 @external_local_function_caller(i32 %i) {
; STATIC-LABEL: @external_local_function_caller
; STATIC: bl external_local_function
; STATIC-NOT: nop
; STATIC-NEXT: nop
; STATIC: blr
; CHECK-LABEL: @external_local_function_caller
; CHECK: bl external_local_function
; CHECK-NOT: nop
; CHECK-NEXT: nop
; CHECK: blr
}
@ -275,7 +275,7 @@ define signext i32 @weak_preemptable_function_caller(i32 %i) {
; STATIC-LABEL: @weak_preemptable_function_caller
; STATIC: bl weak_preemptable_function
; STATIC-NOT: nop
; STATIC-NEXT: nop
; STATIC: blr
; CHECK-LABEL: @weak_preemptable_function_caller

6
llvm/test/CodeGen/PowerPC/xray-tail-call-hidden.ll
View File

@ -12,12 +12,12 @@ define i32 @caller() nounwind noinline uwtable "function-instrument"="xray-alway
; CHECK-NEXT: nop
; CHECK-NEXT: mtlr 0
; CHECK-LABEL: .Ltmp1:
; CHECK: bl callee
; CHECK-NEXT: nop
%retval = tail call i32 @callee()
ret i32 %retval
; CHECK-LABEL: .Ltmp2:
; CHECK: b callee
; CHECK-NEXT: nop
; CHECK-NEXT: std 0, -8(1)
; CHECK: std 0, -8(1)
; CHECK-NEXT: mflr 0
; CHECK-NEXT: bl __xray_FunctionExit
; CHECK-NEXT: nop