[llvm] r211349 - Emit the ARM build attributes ABI_PCS_wchar_t and ABI_enum_size.
Oliver Stannard
oliver.stannard at arm.com
Fri Jun 20 03:08:12 PDT 2014
Author: olista01
Date: Fri Jun 20 05:08:11 2014
New Revision: 211349
URL: http://llvm.org/viewvc/llvm-project?rev=211349&view=rev
Log:
Emit the ARM build attributes ABI_PCS_wchar_t and ABI_enum_size.
Emit the ARM build attributes ABI_PCS_wchar_t and ABI_enum_size based on
module flags metadata.
Added:
llvm/trunk/test/CodeGen/ARM/metadata-default.ll
llvm/trunk/test/CodeGen/ARM/metadata-short-enums.ll
llvm/trunk/test/CodeGen/ARM/metadata-short-wchar.ll
Modified:
llvm/trunk/docs/LangRef.rst
llvm/trunk/include/llvm/Support/ARMBuildAttributes.h
llvm/trunk/lib/Target/ARM/ARMAsmPrinter.cpp
Modified: llvm/trunk/docs/LangRef.rst
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/docs/LangRef.rst?rev=211349&r1=211348&r2=211349&view=diff
==============================================================================
--- llvm/trunk/docs/LangRef.rst (original)
+++ llvm/trunk/docs/LangRef.rst Fri Jun 20 05:08:11 2014
@@ -3146,6 +3146,42 @@ Each individual option is required to be
linker, or an option that is reserved by the target specific assembly writer or
object file emitter. No other aspect of these options is defined by the IR.
+C type width Module Flags Metadata
+----------------------------------
+
+The ARM backend emits a section into each generated object file describing the
+options that it was compiled with (in a compiler-independent way) to prevent
+linking incompatible objects, and to allow automatic library selection. Some
+of these options are not visible at the IR level, namely wchar_t width and enum
+width.
+
+To pass this information to the backend, these options are encoded in module
+flags metadata, using the following key-value pairs:
+
+.. list-table::
+ :header-rows: 1
+ :widths: 30 70
+
+ * - Key
+ - Value
+
+ * - short_wchar
+ - * 0 --- sizeof(wchar_t) == 4
+ * 1 --- sizeof(wchar_t) == 2
+
+ * - short_enum
+ - * 0 --- Enums are at least as large as an ``int``.
+ * 1 --- Enums are stored in the smallest integer type which can
+ represent all of its values.
+
+For example, the following metadata section specifies that the module was
+compiled with a ``wchar_t`` width of 4 bytes, and the underlying type of an
+enum is the smallest type which can represent all of its values::
+
+ !llvm.module.flags = !{!0, !1}
+ !0 = metadata !{i32 1, metadata !"short_wchar", i32 1}
+ !1 = metadata !{i32 1, metadata !"short_enum", i32 0}
+
.. _intrinsicglobalvariables:
Intrinsic Global Variables
Modified: llvm/trunk/include/llvm/Support/ARMBuildAttributes.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Support/ARMBuildAttributes.h?rev=211349&r1=211348&r2=211349&view=diff
==============================================================================
--- llvm/trunk/include/llvm/Support/ARMBuildAttributes.h (original)
+++ llvm/trunk/include/llvm/Support/ARMBuildAttributes.h Fri Jun 20 05:08:11 2014
@@ -159,6 +159,11 @@ enum {
AddressDirect = 1, // Address imported data directly
AddressGOT = 2, // Address imported data indirectly (via GOT)
+ // Tag_ABI_PCS_wchar_t, (=18), uleb128
+ WCharProhibited = 0, // wchar_t is not used
+ WCharWidth2Bytes = 2, // sizeof(wchar_t) == 2
+ WCharWidth4Bytes = 4, // sizeof(wchar_t) == 4
+
// Tag_ABI_FP_denormal, (=20), uleb128
PreserveFPSign = 2, // sign when flushed-to-zero is preserved
@@ -166,6 +171,16 @@ enum {
AllowRTABI = 2, // numbers, infinities, and one quiet NaN (see [RTABI])
AllowIEE754 = 3, // this code to use all the IEEE 754-defined FP encodings
+ // Tag_ABI_enum_size, (=26), uleb128
+ EnumProhibited = 0, // The user prohibited the use of enums when building
+ // this entity.
+ EnumSmallest = 1, // Enum is smallest container big enough to hold all
+ // values.
+ Enum32Bit = 2, // Enum is at least 32 bits.
+ Enum32BitABI = 3, // Every enumeration visible across an ABI-complying
+ // interface contains a value needing 32 bits to encode
+ // it; other enums can be containerized.
+
// Tag_ABI_HardFP_use, (=27), uleb128
HardFPImplied = 0, // FP use should be implied by Tag_FP_arch
HardFPSinglePrecision = 1, // Single-precision only
Modified: llvm/trunk/lib/Target/ARM/ARMAsmPrinter.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/ARM/ARMAsmPrinter.cpp?rev=211349&r1=211348&r2=211349&view=diff
==============================================================================
--- llvm/trunk/lib/Target/ARM/ARMAsmPrinter.cpp (original)
+++ llvm/trunk/lib/Target/ARM/ARMAsmPrinter.cpp Fri Jun 20 05:08:11 2014
@@ -730,6 +730,32 @@ void ARMAsmPrinter::emitAttributes() {
if (Subtarget->hasDivideInARMMode() && !Subtarget->hasV8Ops())
ATS.emitAttribute(ARMBuildAttrs::DIV_use, ARMBuildAttrs::AllowDIVExt);
+ if (MMI) {
+ if (const Module *SourceModule = MMI->getModule()) {
+ // ABI_PCS_wchar_t to indicate wchar_t width
+ // FIXME: There is no way to emit value 0 (wchar_t prohibited).
+ if (auto WCharWidthValue = cast_or_null<ConstantInt>(
+ SourceModule->getModuleFlag("wchar_size"))) {
+ int WCharWidth = WCharWidthValue->getZExtValue();
+ assert((WCharWidth == 2 || WCharWidth == 4) &&
+ "wchar_t width must be 2 or 4 bytes");
+ ATS.emitAttribute(ARMBuildAttrs::ABI_PCS_wchar_t, WCharWidth);
+ }
+
+ // ABI_enum_size to indicate enum width
+ // FIXME: There is no way to emit value 0 (enums prohibited) or value 3
+ // (all enums contain a value needing 32 bits to encode).
+ if (auto EnumWidthValue = cast_or_null<ConstantInt>(
+ SourceModule->getModuleFlag("min_enum_size"))) {
+ int EnumWidth = EnumWidthValue->getZExtValue();
+ assert((EnumWidth == 1 || EnumWidth == 4) &&
+ "Minimum enum width must be 1 or 4 bytes");
+ int EnumBuildAttr = EnumWidth == 1 ? 1 : 2;
+ ATS.emitAttribute(ARMBuildAttrs::ABI_enum_size, EnumBuildAttr);
+ }
+ }
+ }
+
if (Subtarget->hasTrustZone() && Subtarget->hasVirtualization())
ATS.emitAttribute(ARMBuildAttrs::Virtualization_use,
ARMBuildAttrs::AllowTZVirtualization);
Added: llvm/trunk/test/CodeGen/ARM/metadata-default.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/ARM/metadata-default.ll?rev=211349&view=auto
==============================================================================
--- llvm/trunk/test/CodeGen/ARM/metadata-default.ll (added)
+++ llvm/trunk/test/CodeGen/ARM/metadata-default.ll Fri Jun 20 05:08:11 2014
@@ -0,0 +1,16 @@
+; RUN: llc < %s -mtriple=armv7-linux-gnueabi | FileCheck %s
+
+target datalayout = "e-m:e-p:32:32-i64:64-v128:64:128-n32-S64"
+target triple = "armv7--none-eabi"
+
+define i32 @f(i64 %z) {
+ ret i32 0
+}
+
+!llvm.module.flags = !{!0, !1}
+
+!0 = metadata !{i32 1, metadata !"wchar_size", i32 4}
+!1 = metadata !{i32 1, metadata !"min_enum_size", i32 4}
+
+; CHECK: .eabi_attribute 18, 4 @ Tag_ABI_PCS_wchar_t
+; CHECK: .eabi_attribute 26, 2 @ Tag_ABI_enum_size
Added: llvm/trunk/test/CodeGen/ARM/metadata-short-enums.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/ARM/metadata-short-enums.ll?rev=211349&view=auto
==============================================================================
--- llvm/trunk/test/CodeGen/ARM/metadata-short-enums.ll (added)
+++ llvm/trunk/test/CodeGen/ARM/metadata-short-enums.ll Fri Jun 20 05:08:11 2014
@@ -0,0 +1,16 @@
+; RUN: llc < %s | FileCheck %s
+
+target datalayout = "e-m:e-p:32:32-i64:64-v128:64:128-n32-S64"
+target triple = "armv7--none-eabi"
+
+define i32 @f(i64 %z) {
+ ret i32 0
+}
+
+!llvm.module.flags = !{!0, !1}
+
+!0 = metadata !{i32 1, metadata !"wchar_size", i32 4}
+!1 = metadata !{i32 1, metadata !"min_enum_size", i32 1}
+
+; CHECK: .eabi_attribute 18, 4 @ Tag_ABI_PCS_wchar_t
+; CHECK: .eabi_attribute 26, 1 @ Tag_ABI_enum_size
Added: llvm/trunk/test/CodeGen/ARM/metadata-short-wchar.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/ARM/metadata-short-wchar.ll?rev=211349&view=auto
==============================================================================
--- llvm/trunk/test/CodeGen/ARM/metadata-short-wchar.ll (added)
+++ llvm/trunk/test/CodeGen/ARM/metadata-short-wchar.ll Fri Jun 20 05:08:11 2014
@@ -0,0 +1,16 @@
+; RUN: llc < %s | FileCheck %s
+
+target datalayout = "e-m:e-p:32:32-i64:64-v128:64:128-n32-S64"
+target triple = "armv7--none-eabi"
+
+define i32 @f(i64 %z) {
+ ret i32 0
+}
+
+!llvm.module.flags = !{!0, !1}
+
+!0 = metadata !{i32 1, metadata !"wchar_size", i32 2}
+!1 = metadata !{i32 1, metadata !"min_enum_size", i32 4}
+
+; CHECK: .eabi_attribute 18, 2 @ Tag_ABI_PCS_wchar_t
+; CHECK: .eabi_attribute 26, 2 @ Tag_ABI_enum_size
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