Author: Ben Dunbobbin Date: 2020-09-17T13:23:29+02:00 New Revision: 80e2fc1e6e68d6ed57dccc03c6a5121e216bfd43
URL: https://github.com/llvm/llvm-project/commit/80e2fc1e6e68d6ed57dccc03c6a5121e216bfd43 DIFF: https://github.com/llvm/llvm-project/commit/80e2fc1e6e68d6ed57dccc03c6a5121e216bfd43.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 (cherry picked from commit 4cb016cd2d8467c572b2e5c5d34f376ee79e4ac1) 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$local@TLSLDM +; CHECK: leal __libc_resp@TLSLD entry: %retval = alloca i32 ; <i32*> [#uses=1] %"alloca point" = bitcast i32 0 to i32 ; <i32> [#uses=0] @@ -27,7 +27,7 @@ return: ; preds = %entry define i32 @bar() { ; CHECK-LABEL: bar: -; CHECK: leal .L__libc_resp$local@TLSLDM +; CHECK: leal __libc_resp@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@GOT(%eax), %eax +@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@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@GOT(%eax), %eax +@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@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@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@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 } _______________________________________________ llvm-branch-commits mailing list llvm-branch-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-branch-commits
