[llvm-commits] [llvm] r95945 - in /llvm/trunk: docs/LangRef.html include/llvm/Attributes.h lib/AsmParser/LLParser.cpp lib/AsmParser/LLParser.h lib/VMCore/Attributes.cpp test/Feature/alignment.ll
Charles Davis
cdavis at mines.edu
Thu Feb 11 16:31:16 PST 2010
Author: cdavis
Date: Thu Feb 11 18:31:15 2010
New Revision: 95945
URL: http://llvm.org/viewvc/llvm-project?rev=95945&view=rev
Log:
Add a new function attribute, 'alignstack'. It will indicate (when the backends
implement support for it) that the stack should be forcibly realigned in the
prologue (and the process reversed in the epilogue).
Modified:
llvm/trunk/docs/LangRef.html
llvm/trunk/include/llvm/Attributes.h
llvm/trunk/lib/AsmParser/LLParser.cpp
llvm/trunk/lib/AsmParser/LLParser.h
llvm/trunk/lib/VMCore/Attributes.cpp
llvm/trunk/test/Feature/alignment.ll
Modified: llvm/trunk/docs/LangRef.html
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/docs/LangRef.html?rev=95945&r1=95944&r2=95945&view=diff
==============================================================================
--- llvm/trunk/docs/LangRef.html (original)
+++ llvm/trunk/docs/LangRef.html Thu Feb 11 18:31:15 2010
@@ -1078,6 +1078,11 @@
</div>
<dl>
+ <dt><tt><b>alignstack(<<em>n</em>>)</b></tt></dt>
+ <dd>This attribute indicates that, when emitting the prologue and epilogue,
+ the backend should forcibly align the stack pointer. Specify the
+ desired alignment, which must be a power of two, in parentheses.
+
<dt><tt><b>alwaysinline</b></tt></dt>
<dd>This attribute indicates that the inliner should attempt to inline this
function into callers whenever possible, ignoring any active inlining size
Modified: llvm/trunk/include/llvm/Attributes.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Attributes.h?rev=95945&r1=95944&r2=95945&view=diff
==============================================================================
--- llvm/trunk/include/llvm/Attributes.h (original)
+++ llvm/trunk/include/llvm/Attributes.h Thu Feb 11 18:31:15 2010
@@ -60,6 +60,11 @@
const Attributes Naked = 1<<24; ///< Naked function
const Attributes InlineHint = 1<<25; ///< source said inlining was
///desirable
+const Attributes StackAlignment = 31<<26; ///< Alignment of stack for
+ ///function (5 bits) stored as log2
+ ///of alignment with +1 bias
+ ///0 means unaligned (different from
+ ///alignstack(1))
/// @brief Attributes that only apply to function parameters.
const Attributes ParameterOnly = ByVal | Nest | StructRet | NoCapture;
@@ -68,7 +73,7 @@
/// be used on return values or function parameters.
const Attributes FunctionOnly = NoReturn | NoUnwind | ReadNone | ReadOnly |
NoInline | AlwaysInline | OptimizeForSize | StackProtect | StackProtectReq |
- NoRedZone | NoImplicitFloat | Naked | InlineHint;
+ NoRedZone | NoImplicitFloat | Naked | InlineHint | StackAlignment;
/// @brief Parameter attributes that do not apply to vararg call arguments.
const Attributes VarArgsIncompatible = StructRet;
@@ -105,6 +110,28 @@
return 1U << ((Align >> 16) - 1);
}
+/// This turns an int stack alignment (which must be a power of 2) into
+/// the form used internally in Attributes.
+inline Attributes constructStackAlignmentFromInt(unsigned i) {
+ // Default alignment, allow the target to define how to align it.
+ if (i == 0)
+ return 0;
+
+ assert(isPowerOf2_32(i) && "Alignment must be a power of two.");
+ assert(i <= 0x40000000 && "Alignment too large.");
+ return (Log2_32(i)+1) << 26;
+}
+
+/// This returns the stack alignment field of an attribute as a byte alignment
+/// value.
+inline unsigned getStackAlignmentFromAttrs(Attributes A) {
+ Attributes StackAlign = A & Attribute::StackAlignment;
+ if (StackAlign == 0)
+ return 0;
+
+ return 1U << ((StackAlign >> 26) - 1);
+}
+
/// The set of Attributes set in Attributes is converted to a
/// string of equivalent mnemonics. This is, presumably, for writing out
Modified: llvm/trunk/lib/AsmParser/LLParser.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/AsmParser/LLParser.cpp?rev=95945&r1=95944&r2=95945&view=diff
==============================================================================
--- llvm/trunk/lib/AsmParser/LLParser.cpp (original)
+++ llvm/trunk/lib/AsmParser/LLParser.cpp Thu Feb 11 18:31:15 2010
@@ -956,6 +956,14 @@
case lltok::kw_noimplicitfloat: Attrs |= Attribute::NoImplicitFloat; break;
case lltok::kw_naked: Attrs |= Attribute::Naked; break;
+ case lltok::kw_alignstack: {
+ unsigned Alignment;
+ if (ParseOptionalStackAlignment(Alignment))
+ return true;
+ Attrs |= Attribute::constructStackAlignmentFromInt(Alignment);
+ continue;
+ }
+
case lltok::kw_align: {
unsigned Alignment;
if (ParseOptionalAlignment(Alignment))
@@ -963,6 +971,7 @@
Attrs |= Attribute::constructAlignmentFromInt(Alignment);
continue;
}
+
}
Lex.Lex();
}
@@ -1131,6 +1140,25 @@
return false;
}
+/// ParseOptionalStackAlignment
+/// ::= /* empty */
+/// ::= 'alignstack' '(' 4 ')'
+bool LLParser::ParseOptionalStackAlignment(unsigned &Alignment) {
+ Alignment = 0;
+ if (!EatIfPresent(lltok::kw_alignstack))
+ return false;
+ LocTy ParenLoc = Lex.getLoc();
+ if (!EatIfPresent(lltok::lparen))
+ return Error(ParenLoc, "expected '('");
+ LocTy AlignLoc = Lex.getLoc();
+ if (ParseUInt32(Alignment)) return true;
+ ParenLoc = Lex.getLoc();
+ if (!EatIfPresent(lltok::rparen))
+ return Error(ParenLoc, "expected ')'");
+ if (!isPowerOf2_32(Alignment))
+ return Error(AlignLoc, "stack alignment is not a power of two");
+ return false;
+}
/// ParseIndexList - This parses the index list for an insert/extractvalue
/// instruction. This sets AteExtraComma in the case where we eat an extra
Modified: llvm/trunk/lib/AsmParser/LLParser.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/AsmParser/LLParser.h?rev=95945&r1=95944&r2=95945&view=diff
==============================================================================
--- llvm/trunk/lib/AsmParser/LLParser.h (original)
+++ llvm/trunk/lib/AsmParser/LLParser.h Thu Feb 11 18:31:15 2010
@@ -169,6 +169,7 @@
bool ParseOptionalVisibility(unsigned &Visibility);
bool ParseOptionalCallingConv(CallingConv::ID &CC);
bool ParseOptionalAlignment(unsigned &Alignment);
+ bool ParseOptionalStackAlignment(unsigned &Alignment);
bool ParseInstructionMetadata(SmallVectorImpl<std::pair<unsigned,
MDNode *> > &);
bool ParseOptionalCommaAlign(unsigned &Alignment, bool &AteExtraComma);
Modified: llvm/trunk/lib/VMCore/Attributes.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/VMCore/Attributes.cpp?rev=95945&r1=95944&r2=95945&view=diff
==============================================================================
--- llvm/trunk/lib/VMCore/Attributes.cpp (original)
+++ llvm/trunk/lib/VMCore/Attributes.cpp Thu Feb 11 18:31:15 2010
@@ -70,6 +70,11 @@
Result += "noimplicitfloat ";
if (Attrs & Attribute::Naked)
Result += "naked ";
+ if (Attrs & Attribute::StackAlignment) {
+ Result += "alignstack(";
+ Result += utostr(Attribute::getStackAlignmentFromAttrs(Attrs));
+ Result += ") ";
+ }
if (Attrs & Attribute::Alignment) {
Result += "align ";
Result += utostr(Attribute::getAlignmentFromAttrs(Attrs));
Modified: llvm/trunk/test/Feature/alignment.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Feature/alignment.ll?rev=95945&r1=95944&r2=95945&view=diff
==============================================================================
--- llvm/trunk/test/Feature/alignment.ll (original)
+++ llvm/trunk/test/Feature/alignment.ll Thu Feb 11 18:31:15 2010
@@ -19,3 +19,7 @@
ret i32* %X
}
+define void @test3() alignstack(16) {
+ ret void
+}
+
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