[llvm] 4cb016c - [X86][ELF] Prefer lowering MC_GlobalAddress operands to .Lfoo$local for STV_DEFAULT only
Ben Dunbobbin via llvm-commits
llvm-commits at lists.llvm.org
Thu Aug 13 16:09:30 PDT 2020
Author: Ben Dunbobbin
Date: 2020-08-14T00:09:15+01:00
New Revision: 4cb016cd2d8467c572b2e5c5d34f376ee79e4ac1
URL: https://github.com/llvm/llvm-project/commit/4cb016cd2d8467c572b2e5c5d34f376ee79e4ac1
DIFF: https://github.com/llvm/llvm-project/commit/4cb016cd2d8467c572b2e5c5d34f376ee79e4ac1.diff
LOG: [X86][ELF] Prefer lowering MC_GlobalAddress operands to .Lfoo$local for STV_DEFAULT only
This patch restricts the behaviour of referencing via .Lfoo$local
local aliases, introduced in https://reviews.llvm.org/D73230, to
STV_DEFAULT globals only.
Hidden symbols via --fvisiblity=hidden (https://gcc.gnu.org/wiki/Visibility)
is an important scenario.
Benefits:
- Improves the size of object files by using fewer STT_SECTION symbols.
- The code reads a bit better (it was not obvious to me without going
back to the code reviews why the canBenefitFromLocalAlias function
currently doesn't consider visibility).
- There is also a side benefit in restoring the effectiveness of the
--wrap linker option and making the behavior of --wrap consistent
between LTO and normal builds for references within a translation-unit.
Note: this --wrap behavior (which is specific to LLD) should not be
considered reliable. See comments on https://reviews.llvm.org/D73230
for more.
Differential Revision: https://reviews.llvm.org/D85782
Added:
Modified:
llvm/lib/IR/Globals.cpp
llvm/test/CodeGen/AArch64/emutls.ll
llvm/test/CodeGen/ARM/emutls.ll
llvm/test/CodeGen/X86/2008-03-12-ThreadLocalAlias.ll
llvm/test/CodeGen/X86/linux-preemption.ll
llvm/test/CodeGen/X86/semantic-interposition-comdat.ll
llvm/test/CodeGen/X86/tailcallpic1.ll
llvm/test/CodeGen/X86/tailcallpic3.ll
llvm/test/CodeGen/X86/tailccpic1.ll
Removed:
################################################################################
diff --git a/llvm/lib/IR/Globals.cpp b/llvm/lib/IR/Globals.cpp
index dd8e62164de1..ed946ef3fd12 100644
--- a/llvm/lib/IR/Globals.cpp
+++ b/llvm/lib/IR/Globals.cpp
@@ -104,7 +104,8 @@ bool GlobalValue::isInterposable() const {
bool GlobalValue::canBenefitFromLocalAlias() const {
// See AsmPrinter::getSymbolPreferLocal().
- return GlobalObject::isExternalLinkage(getLinkage()) && !isDeclaration() &&
+ return hasDefaultVisibility() &&
+ GlobalObject::isExternalLinkage(getLinkage()) && !isDeclaration() &&
!isa<GlobalIFunc>(this) && !hasComdat();
}
diff --git a/llvm/test/CodeGen/AArch64/emutls.ll b/llvm/test/CodeGen/AArch64/emutls.ll
index 85d2c1a3b315..25be391bbfaa 100644
--- a/llvm/test/CodeGen/AArch64/emutls.ll
+++ b/llvm/test/CodeGen/AArch64/emutls.ll
@@ -155,7 +155,6 @@ entry:
; ARM64: .data{{$}}
; ARM64: .globl __emutls_v.i4
; ARM64-LABEL: __emutls_v.i4:
-; ARM64-NEXT: .L__emutls_v.i4$local:
; ARM64-NEXT: .xword 4
; ARM64-NEXT: .xword 4
; ARM64-NEXT: .xword 0
@@ -163,7 +162,6 @@ entry:
; ARM64: .section .rodata,
; ARM64-LABEL: __emutls_t.i4:
-; ARM64-NEXT: .L__emutls_t.i4$local:
; ARM64-NEXT: .word 15
; ARM64-NOT: __emutls_v.i5:
diff --git a/llvm/test/CodeGen/ARM/emutls.ll b/llvm/test/CodeGen/ARM/emutls.ll
index 4327086685e9..92b656d9ba09 100644
--- a/llvm/test/CodeGen/ARM/emutls.ll
+++ b/llvm/test/CodeGen/ARM/emutls.ll
@@ -238,7 +238,6 @@ entry:
; ARM32: .data{{$}}
; ARM32: .globl __emutls_v.i4
; ARM32-LABEL: __emutls_v.i4:
-; ARM32-NEXT: .L__emutls_v.i4$local:
; ARM32-NEXT: .long 4
; ARM32-NEXT: .long 4
; ARM32-NEXT: .long 0
@@ -246,7 +245,6 @@ entry:
; ARM32: .section .rodata,
; ARM32-LABEL: __emutls_t.i4:
-; ARM32-NEXT: .L__emutls_t.i4$local:
; ARM32-NEXT: .long 15
; ARM32-NOT: __emutls_v.i5:
diff --git a/llvm/test/CodeGen/X86/2008-03-12-ThreadLocalAlias.ll b/llvm/test/CodeGen/X86/2008-03-12-ThreadLocalAlias.ll
index 89d249c09178..2ca003e052aa 100644
--- a/llvm/test/CodeGen/X86/2008-03-12-ThreadLocalAlias.ll
+++ b/llvm/test/CodeGen/X86/2008-03-12-ThreadLocalAlias.ll
@@ -12,7 +12,7 @@ target triple = "i386-pc-linux-gnu"
define i32 @foo() {
; CHECK-LABEL: foo:
-; CHECK: leal .L__libc_resp$local at TLSLDM
+; CHECK: leal __libc_resp at TLSLD
entry:
%retval = alloca i32 ; <i32*> [#uses=1]
%"alloca point" = bitcast i32 0 to i32 ; <i32> [#uses=0]
@@ -27,7 +27,7 @@ return: ; preds = %entry
define i32 @bar() {
; CHECK-LABEL: bar:
-; CHECK: leal .L__libc_resp$local at TLSLDM
+; CHECK: leal __libc_resp at TLSLD
entry:
%retval = alloca i32 ; <i32*> [#uses=1]
%"alloca point" = bitcast i32 0 to i32 ; <i32> [#uses=0]
diff --git a/llvm/test/CodeGen/X86/linux-preemption.ll b/llvm/test/CodeGen/X86/linux-preemption.ll
index 49a7becf1343..15265f401992 100644
--- a/llvm/test/CodeGen/X86/linux-preemption.ll
+++ b/llvm/test/CodeGen/X86/linux-preemption.ll
@@ -20,6 +20,14 @@ define i32* @get_strong_default_global() {
; STATIC: movl $strong_default_global, %eax
; CHECK32: movl strong_default_global at GOT(%eax), %eax
+ at strong_hidden_global = hidden global i32 42
+define i32* @get_hidden_default_global() {
+ ret i32* @strong_hidden_global
+}
+; CHECK: leaq strong_hidden_global(%rip), %rax
+; STATIC: movl $strong_hidden_global, %eax
+; CHECK32: leal strong_hidden_global at GOTOFF(%eax), %eax
+
@weak_default_global = weak global i32 42
define i32* @get_weak_default_global() {
ret i32* @weak_default_global
@@ -96,6 +104,14 @@ define i32* @get_strong_default_alias() {
; STATIC: movl $strong_default_alias, %eax
; CHECK32: movl strong_default_alias at GOT(%eax), %eax
+ at strong_hidden_alias = hidden alias i32, i32* @aliasee
+define i32* @get_strong_hidden_alias() {
+ ret i32* @strong_hidden_alias
+}
+; CHECK: leaq strong_hidden_alias(%rip), %rax
+; STATIC: movl $strong_hidden_alias, %eax
+; CHECK32: leal strong_hidden_alias at GOTOFF(%eax), %eax
+
@weak_default_alias = weak alias i32, i32* @aliasee
define i32* @get_weak_default_alias() {
ret i32* @weak_default_alias
@@ -149,6 +165,16 @@ define void()* @get_strong_default_function() {
; STATIC: movl $strong_default_function, %eax
; CHECK32: movl strong_default_function at GOT(%eax), %eax
+define hidden void @strong_hidden_function() {
+ ret void
+}
+define void()* @get_strong_hidden_function() {
+ ret void()* @strong_hidden_function
+}
+; CHECK: leaq strong_hidden_function(%rip), %rax
+; STATIC: movl $strong_hidden_function, %eax
+; CHECK32: leal strong_hidden_function at GOTOFF(%eax), %eax
+
define weak void @weak_default_function() {
ret void
}
@@ -234,6 +260,9 @@ define void()* @get_external_preemptable_function() {
; COMMON: .globl strong_default_alias
; COMMON-NEXT: .set strong_default_alias, aliasee
+; COMMON-NEXT: .globl strong_hidden_alias
+; COMMON-NEXT: .hidden strong_hidden_alias
+; COMMON-NEXT: .set strong_hidden_alias, aliasee
; COMMON-NEXT: .weak weak_default_alias
; COMMON-NEXT: .set weak_default_alias, aliasee
; COMMON-NEXT: .globl strong_local_alias
diff --git a/llvm/test/CodeGen/X86/semantic-interposition-comdat.ll b/llvm/test/CodeGen/X86/semantic-interposition-comdat.ll
index d0efd4d11c95..d11be2d6bd0c 100644
--- a/llvm/test/CodeGen/X86/semantic-interposition-comdat.ll
+++ b/llvm/test/CodeGen/X86/semantic-interposition-comdat.ll
@@ -3,7 +3,7 @@
$comdat_func = comdat any
; CHECK-LABEL: func2:
-; CHECK-NEXT: .Lfunc2$local
+; CHECK-NOT: .Lfunc2$local
declare void @func()
diff --git a/llvm/test/CodeGen/X86/tailcallpic1.ll b/llvm/test/CodeGen/X86/tailcallpic1.ll
index 717cc1fddec9..ed101fcccd2d 100644
--- a/llvm/test/CodeGen/X86/tailcallpic1.ll
+++ b/llvm/test/CodeGen/X86/tailcallpic1.ll
@@ -12,5 +12,5 @@ define fastcc i32 @tailcaller(i32 %in1, i32 %in2) {
entry:
%tmp11 = tail call fastcc i32 @tailcallee( i32 %in1, i32 %in2, i32 %in1, i32 %in2 ) ; <i32> [#uses=1]
ret i32 %tmp11
-; CHECK: jmp .Ltailcallee$local
+; CHECK: jmp tailcallee
}
diff --git a/llvm/test/CodeGen/X86/tailcallpic3.ll b/llvm/test/CodeGen/X86/tailcallpic3.ll
index 13b160aae2f6..edc58052d82f 100644
--- a/llvm/test/CodeGen/X86/tailcallpic3.ll
+++ b/llvm/test/CodeGen/X86/tailcallpic3.ll
@@ -16,7 +16,7 @@ entry:
ret void
}
; CHECK: tailcall_hidden:
-; CHECK: jmp .Ltailcallee_hidden$local
+; CHECK: jmp tailcallee_hidden
define internal void @tailcallee_internal() {
entry:
diff --git a/llvm/test/CodeGen/X86/tailccpic1.ll b/llvm/test/CodeGen/X86/tailccpic1.ll
index dbdc56aa61c7..de8f2219bc2f 100644
--- a/llvm/test/CodeGen/X86/tailccpic1.ll
+++ b/llvm/test/CodeGen/X86/tailccpic1.ll
@@ -12,5 +12,5 @@ define tailcc i32 @tailcaller(i32 %in1, i32 %in2) {
entry:
%tmp11 = tail call tailcc i32 @tailcallee( i32 %in1, i32 %in2, i32 %in1, i32 %in2 ) ; <i32> [#uses=1]
ret i32 %tmp11
-; CHECK: jmp .Ltailcallee$local
+; CHECK: jmp tailcallee
}
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