[llvm-commits] [llvm] r102515 - in /llvm/trunk: include/llvm/CodeGen/AsmPrinter.h lib/CodeGen/AsmPrinter/AsmPrinter.cpp test/CodeGen/X86/alignment.ll test/CodeGen/X86/unaligned-load.ll test/FrontendC/cstring-align.c
Chris Lattner
sabre at nondot.org
Wed Apr 28 12:58:08 PDT 2010
Author: lattner
Date: Wed Apr 28 14:58:07 2010
New Revision: 102515
URL: http://llvm.org/viewvc/llvm-project?rev=102515&view=rev
Log:
Rework global alignment computation again. Now we do round up
alignment of globals to the preferred alignment, but only when
there is no section specified on the global (by far the common
case).
Modified:
llvm/trunk/include/llvm/CodeGen/AsmPrinter.h
llvm/trunk/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
llvm/trunk/test/CodeGen/X86/alignment.ll
llvm/trunk/test/CodeGen/X86/unaligned-load.ll
llvm/trunk/test/FrontendC/cstring-align.c
Modified: llvm/trunk/include/llvm/CodeGen/AsmPrinter.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/CodeGen/AsmPrinter.h?rev=102515&r1=102514&r2=102515&view=diff
==============================================================================
--- llvm/trunk/include/llvm/CodeGen/AsmPrinter.h (original)
+++ llvm/trunk/include/llvm/CodeGen/AsmPrinter.h Wed Apr 28 14:58:07 2010
@@ -204,12 +204,8 @@
/// EmitAlignment - Emit an alignment directive to the specified power of
/// two boundary. For example, if you pass in 3 here, you will get an 8
/// byte alignment. If a global value is specified, and if that global has
- /// an explicit alignment requested, it will unconditionally override the
- /// alignment request.
- ///
- /// The algorithm is:
- /// Align = NumBits;
- /// if (GV && GV->hasalignment) Align = GV->getAlignment();
+ /// an explicit alignment requested, it will override the alignment request
+ /// if required for correctness.
///
void EmitAlignment(unsigned NumBits, const GlobalValue *GV = 0) const;
@@ -218,7 +214,6 @@
/// it if appropriate.
void EmitBasicBlockStart(const MachineBasicBlock *MBB) const;
-
/// EmitGlobalConstant - Print a general LLVM constant to the .s file.
void EmitGlobalConstant(const Constant *CV, unsigned AddrSpace = 0);
Modified: llvm/trunk/lib/CodeGen/AsmPrinter/AsmPrinter.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/AsmPrinter/AsmPrinter.cpp?rev=102515&r1=102514&r2=102515&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/AsmPrinter/AsmPrinter.cpp (original)
+++ llvm/trunk/lib/CodeGen/AsmPrinter/AsmPrinter.cpp Wed Apr 28 14:58:07 2010
@@ -61,6 +61,35 @@
}
+/// getGVAlignmentLog2 - Return the alignment to use for the specified global
+/// value in log2 form. This rounds up to the preferred alignment if possible
+/// and legal.
+static unsigned getGVAlignmentLog2(const GlobalValue *GV, const TargetData &TD,
+ unsigned InBits = 0) {
+ unsigned NumBits = 0;
+ if (const GlobalVariable *GVar = dyn_cast<GlobalVariable>(GV))
+ NumBits = TD.getPreferredAlignmentLog(GVar);
+
+ // If InBits is specified, round it to it.
+ if (InBits > NumBits)
+ NumBits = InBits;
+
+ // If the GV has a specified alignment, take it into account.
+ if (GV->getAlignment() == 0)
+ return NumBits;
+
+ unsigned GVAlign = Log2_32(GV->getAlignment());
+
+ // If the GVAlign is larger than NumBits, or if we are required to obey
+ // NumBits because the GV has an assigned section, obey it.
+ if (GVAlign > NumBits || GV->hasSection())
+ NumBits = GVAlign;
+ return NumBits;
+}
+
+
+
+
AsmPrinter::AsmPrinter(TargetMachine &tm, MCStreamer &Streamer)
: MachineFunctionPass(&ID),
TM(tm), MAI(tm.getMCAsmInfo()),
@@ -227,16 +256,12 @@
SectionKind GVKind = TargetLoweringObjectFile::getKindForGlobal(GV, TM);
const TargetData *TD = TM.getTargetData();
- unsigned Size = TD->getTypeAllocSize(GV->getType()->getElementType());
+ uint64_t Size = TD->getTypeAllocSize(GV->getType()->getElementType());
// If the alignment is specified, we *must* obey it. Overaligning a global
// with a specified alignment is a prompt way to break globals emitted to
// sections and expected to be contiguous (e.g. ObjC metadata).
- unsigned AlignLog;
- if (unsigned GVAlign = GV->getAlignment())
- AlignLog = Log2_32(GVAlign);
- else
- AlignLog = TD->getPreferredAlignmentLog(GV);
+ unsigned AlignLog = getGVAlignmentLog2(GV, *TD);
// Handle common and BSS local symbols (.lcomm).
if (GVKind.isCommon() || GVKind.isBSSLocal()) {
@@ -1010,7 +1035,7 @@
unsigned Align = Log2_32(TD->getPointerPrefAlignment());
if (GV->getName() == "llvm.global_ctors") {
OutStreamer.SwitchSection(getObjFileLowering().getStaticCtorSection());
- EmitAlignment(Align, 0);
+ EmitAlignment(Align);
EmitXXStructorList(GV->getInitializer());
if (TM.getRelocationModel() == Reloc::Static &&
@@ -1024,7 +1049,7 @@
if (GV->getName() == "llvm.global_dtors") {
OutStreamer.SwitchSection(getObjFileLowering().getStaticDtorSection());
- EmitAlignment(Align, 0);
+ EmitAlignment(Align);
EmitXXStructorList(GV->getInitializer());
if (TM.getRelocationModel() == Reloc::Static &&
@@ -1153,20 +1178,13 @@
// EmitAlignment - Emit an alignment directive to the specified power of
// two boundary. For example, if you pass in 3 here, you will get an 8
// byte alignment. If a global value is specified, and if that global has
-// an explicit alignment requested, it will unconditionally override the
-// alignment request. However, if ForcedAlignBits is specified, this value
-// has final say: the ultimate alignment will be the max of ForcedAlignBits
-// and the alignment computed with NumBits and the global.
-//
-// The algorithm is:
-// Align = NumBits;
-// if (GV && GV->hasalignment) Align = GV->getAlignment();
+// an explicit alignment requested, it will override the alignment request
+// if required for correctness.
//
void AsmPrinter::EmitAlignment(unsigned NumBits, const GlobalValue *GV) const {
- if (GV && GV->getAlignment())
- NumBits = Log2_32(GV->getAlignment());
+ if (GV) NumBits = getGVAlignmentLog2(GV, *TM.getTargetData(), NumBits);
- if (NumBits == 0) return; // No need to emit alignment.
+ if (NumBits == 0) return; // 1-byte aligned: no need to emit alignment.
if (getCurrentSection()->getKind().isText())
OutStreamer.EmitCodeAlignment(1 << NumBits);
Modified: llvm/trunk/test/CodeGen/X86/alignment.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/alignment.ll?rev=102515&r1=102514&r2=102515&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/X86/alignment.ll (original)
+++ llvm/trunk/test/CodeGen/X86/alignment.ll Wed Apr 28 14:58:07 2010
@@ -6,7 +6,7 @@
; CHECK: .bss
; CHECK: .globl GlobalA
-; CHECK: .align 8
+; CHECK: .align 16
; CHECK: GlobalA:
; CHECK: .zero 384
@@ -15,4 +15,29 @@
; PR6921
@GlobalB = common global { [384 x i8] } zeroinitializer, align 8
-; CHECK: .comm GlobalB,384,8
\ No newline at end of file
+; CHECK: .comm GlobalB,384,16
+
+
+ at GlobalC = common global { [384 x i8] } zeroinitializer, align 2
+
+; CHECK: .comm GlobalC,384,16
+
+
+
+; This cannot get rounded up to the preferred alignment (16) if they have an
+; explicit alignment specified *and* a section specified.
+ at GlobalAS = global { [384 x i8] } zeroinitializer, align 8, section "foo"
+
+; CHECK: .globl GlobalAS
+; CHECK: .align 8
+; CHECK: GlobalAS:
+; CHECK: .zero 384
+
+; Common variables should not get rounded up to the preferred alignment (16) if
+; they have an explicit alignment specified and a section specified.
+; PR6921
+ at GlobalBS = common global { [384 x i8] } zeroinitializer, align 8, section "foo"
+; CHECK: .comm GlobalBS,384,8
+
+ at GlobalCS = common global { [384 x i8] } zeroinitializer, align 2, section "foo"
+; CHECK: .comm GlobalCS,384,2
\ No newline at end of file
Modified: llvm/trunk/test/CodeGen/X86/unaligned-load.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/unaligned-load.ll?rev=102515&r1=102514&r2=102515&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/X86/unaligned-load.ll (original)
+++ llvm/trunk/test/CodeGen/X86/unaligned-load.ll Wed Apr 28 14:58:07 2010
@@ -29,8 +29,8 @@
declare void @llvm.memcpy.i64(i8* nocapture, i8* nocapture, i64, i32) nounwind
; CORE2: .section
-; CORE2: .align 3
+; CORE2: .align 4
; CORE2-NEXT: _.str1:
; CORE2-NEXT: .asciz "DHRYSTONE PROGRAM, SOME STRING"
-; CORE2: .align 3
+; CORE2: .align 4
; CORE2-NEXT: _.str3:
Modified: llvm/trunk/test/FrontendC/cstring-align.c
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/FrontendC/cstring-align.c?rev=102515&r1=102514&r2=102515&view=diff
==============================================================================
--- llvm/trunk/test/FrontendC/cstring-align.c (original)
+++ llvm/trunk/test/FrontendC/cstring-align.c Wed Apr 28 14:58:07 2010
@@ -1,6 +1,5 @@
// RUN: %llvmgcc %s -c -Os -m32 -emit-llvm -o - | llc -march=x86 -mtriple=i386-apple-darwin10 | FileCheck %s -check-prefix=DARWIN32
// RUN: %llvmgcc %s -c -Os -m64 -emit-llvm -o - | llc -march=x86-64 -mtriple=x86_64-apple-darwin10 | FileCheck %s -check-prefix=DARWIN64
-// XFAIL: *
// XTARGET: darwin
extern void func(const char *, const char *);
@@ -9,10 +8,10 @@
func("%s: the function name", __func__);
}
-// DARWIN64: .align 3
+// DARWIN64: .align 4
// DARWIN64: ___func__.
// DARWIN64: .asciz "long_function_name"
-// DARWIN32: .align 2
+// DARWIN32: .align 4
// DARWIN32: ___func__.
// DARWIN32: .asciz "long_function_name"
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