[llvm] 9b4f747 - [ms] [llvm-ml] Implement support for PROC NEAR/FAR (#131707)
via llvm-commits
llvm-commits at lists.llvm.org
Fri May 2 15:09:46 PDT 2025
Author: Eric Astor
Date: 2025-05-02T18:09:43-04:00
New Revision: 9b4f747827489c5969ff903c728e65c545f58eaa
URL: https://github.com/llvm/llvm-project/commit/9b4f747827489c5969ff903c728e65c545f58eaa
DIFF: https://github.com/llvm/llvm-project/commit/9b4f747827489c5969ff903c728e65c545f58eaa.diff
LOG: [ms] [llvm-ml] Implement support for PROC NEAR/FAR (#131707)
Matches ML.EXE by translating "ret" instructions inside a `PROC FAR` to "retf", and automatically prepending a `push cs` to all near calls to a `PROC FAR`.
Added:
llvm/include/llvm/MC/MCParser/MCMasmParser.h
llvm/test/tools/llvm-ml/proc_distance.asm
Modified:
llvm/include/llvm/MC/MCSymbolCOFF.h
llvm/lib/MC/MCParser/COFFMasmParser.cpp
llvm/lib/MC/MCParser/MasmParser.cpp
llvm/lib/Target/X86/AsmParser/X86AsmParser.cpp
Removed:
################################################################################
diff --git a/llvm/include/llvm/MC/MCParser/MCMasmParser.h b/llvm/include/llvm/MC/MCParser/MCMasmParser.h
new file mode 100644
index 0000000000000..a34c6eba8bc59
--- /dev/null
+++ b/llvm/include/llvm/MC/MCParser/MCMasmParser.h
@@ -0,0 +1,29 @@
+//===- llvm/MC/MasmParser.h - MASM Parser Interface -------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_MC_MCPARSER_MCMASMPARSER_H
+#define LLVM_MC_MCPARSER_MCMASMPARSER_H
+
+#include "llvm/MC/MCParser/MCAsmParser.h"
+
+namespace llvm {
+
+/// MASM-type assembler parser interface.
+class MCMasmParser : public MCAsmParser {
+public:
+ virtual bool getDefaultRetIsFar() const = 0;
+ virtual void setDefaultRetIsFar(bool IsFar) = 0;
+
+ bool isParsingMasm() const override { return true; }
+
+ static bool classof(const MCAsmParser *AP) { return AP->isParsingMasm(); }
+};
+
+} // end namespace llvm
+
+#endif // LLVM_MC_MCPARSER_MCMASMPARSER_H
diff --git a/llvm/include/llvm/MC/MCSymbolCOFF.h b/llvm/include/llvm/MC/MCSymbolCOFF.h
index 2964c521e8e44..c0ddef5cfee50 100644
--- a/llvm/include/llvm/MC/MCSymbolCOFF.h
+++ b/llvm/include/llvm/MC/MCSymbolCOFF.h
@@ -25,6 +25,7 @@ class MCSymbolCOFF : public MCSymbol {
SF_ClassShift = 0,
SF_SafeSEH = 0x0100,
+ SF_FarProc = 0x0200,
SF_WeakExternalCharacteristicsMask = 0x0E00,
SF_WeakExternalCharacteristicsShift = 9,
};
@@ -66,6 +67,9 @@ class MCSymbolCOFF : public MCSymbol {
modifyFlags(SF_SafeSEH, SF_SafeSEH);
}
+ bool isFarProc() const { return getFlags() & SF_FarProc; }
+ void setIsFarProc() const { modifyFlags(SF_FarProc, SF_FarProc); }
+
static bool classof(const MCSymbol *S) { return S->isCOFF(); }
};
diff --git a/llvm/lib/MC/MCParser/COFFMasmParser.cpp b/llvm/lib/MC/MCParser/COFFMasmParser.cpp
index 8464a2392680b..94f69402ad082 100644
--- a/llvm/lib/MC/MCParser/COFFMasmParser.cpp
+++ b/llvm/lib/MC/MCParser/COFFMasmParser.cpp
@@ -12,7 +12,9 @@
#include "llvm/MC/MCAsmMacro.h"
#include "llvm/MC/MCContext.h"
#include "llvm/MC/MCParser/MCAsmLexer.h"
+#include "llvm/MC/MCParser/MCAsmParser.h"
#include "llvm/MC/MCParser/MCAsmParserExtension.h"
+#include "llvm/MC/MCParser/MCMasmParser.h"
#include "llvm/MC/MCParser/MCTargetAsmParser.h"
#include "llvm/MC/MCSectionCOFF.h"
#include "llvm/MC/MCStreamer.h"
@@ -41,6 +43,7 @@ class COFFMasmParser : public MCAsmParserExtension {
StringRef COMDATSymName, COFF::COMDATType Type,
Align Alignment);
+ bool parseDirectiveModel(StringRef, SMLoc);
bool parseDirectiveProc(StringRef, SMLoc);
bool parseDirectiveEndProc(StringRef, SMLoc);
bool parseDirectiveSegment(StringRef, SMLoc);
@@ -167,7 +170,7 @@ class COFFMasmParser : public MCAsmParserExtension {
// .exit
// .fardata
// .fardata?
- addDirectiveHandler<&COFFMasmParser::IgnoreDirective>(".model");
+ addDirectiveHandler<&COFFMasmParser::parseDirectiveModel>(".model");
// .stack
// .startup
@@ -201,8 +204,13 @@ class COFFMasmParser : public MCAsmParserExtension {
}
/// Stack of active procedure definitions.
- SmallVector<StringRef, 1> CurrentProcedures;
- SmallVector<bool, 1> CurrentProceduresFramed;
+ enum ProcDistance { PROC_DISTANCE_NEAR = 0, PROC_DISTANCE_FAR = 1 };
+ struct ProcInfo {
+ StringRef Name;
+ ProcDistance Distance = PROC_DISTANCE_NEAR;
+ bool IsFramed = false;
+ };
+ SmallVector<ProcInfo, 1> CurrentProcedures;
public:
COFFMasmParser() = default;
@@ -435,48 +443,75 @@ bool COFFMasmParser::parseDirectiveOption(StringRef Directive, SMLoc Loc) {
return false;
}
+/// parseDirectiveModel
+/// ::= ".model" "flat"
+bool COFFMasmParser::parseDirectiveModel(StringRef Directive, SMLoc Loc) {
+ if (!getLexer().is(AsmToken::Identifier))
+ return TokError("expected identifier in directive");
+
+ StringRef ModelType = getTok().getIdentifier();
+ if (!ModelType.equals_insensitive("flat")) {
+ return TokError(
+ "expected 'flat' for memory model; no other models supported");
+ }
+
+ // Ignore; no action necessary.
+ Lex();
+ return false;
+}
+
/// parseDirectiveProc
/// TODO(epastor): Implement parameters and other attributes.
-/// ::= label "proc" [[distance]]
+/// ::= label "proc" [[distance]] [[frame]]
/// statements
/// label "endproc"
bool COFFMasmParser::parseDirectiveProc(StringRef Directive, SMLoc Loc) {
if (!getStreamer().getCurrentFragment())
return Error(getTok().getLoc(), "expected section directive");
- StringRef Label;
- if (getParser().parseIdentifier(Label))
+ ProcInfo Proc;
+ if (getParser().parseIdentifier(Proc.Name))
return Error(Loc, "expected identifier for procedure");
- if (getLexer().is(AsmToken::Identifier)) {
+ while (getLexer().is(AsmToken::Identifier)) {
StringRef nextVal = getTok().getString();
SMLoc nextLoc = getTok().getLoc();
if (nextVal.equals_insensitive("far")) {
- // TODO(epastor): Handle far procedure definitions.
Lex();
- return Error(nextLoc, "far procedure definitions not yet supported");
+ Proc.Distance = PROC_DISTANCE_FAR;
+ nextVal = getTok().getString();
+ nextLoc = getTok().getLoc();
} else if (nextVal.equals_insensitive("near")) {
Lex();
+ Proc.Distance = PROC_DISTANCE_NEAR;
+ nextVal = getTok().getString();
+ nextLoc = getTok().getLoc();
+ } else if (nextVal.equals_insensitive("frame")) {
+ Lex();
+ Proc.IsFramed = true;
nextVal = getTok().getString();
nextLoc = getTok().getLoc();
+ } else {
+ break;
}
}
- MCSymbolCOFF *Sym = cast<MCSymbolCOFF>(getContext().getOrCreateSymbol(Label));
+ MCSymbolCOFF *Sym =
+ cast<MCSymbolCOFF>(getContext().getOrCreateSymbol(Proc.Name));
// Define symbol as simple external function
Sym->setExternal(true);
Sym->setType(COFF::IMAGE_SYM_DTYPE_FUNCTION << COFF::SCT_COMPLEX_TYPE_SHIFT);
+ if (Proc.Distance == PROC_DISTANCE_FAR)
+ Sym->setIsFarProc();
+
+ cast<MCMasmParser>(getParser())
+ .setDefaultRetIsFar(Proc.Distance == PROC_DISTANCE_FAR);
- bool Framed = false;
- if (getLexer().is(AsmToken::Identifier) &&
- getTok().getString().equals_insensitive("frame")) {
- Lex();
- Framed = true;
+ if (Proc.IsFramed) {
getStreamer().emitWinCFIStartProc(Sym, Loc);
}
getStreamer().emitLabel(Sym, Loc);
- CurrentProcedures.push_back(Label);
- CurrentProceduresFramed.push_back(Framed);
+ CurrentProcedures.push_back(std::move(Proc));
return false;
}
bool COFFMasmParser::parseDirectiveEndProc(StringRef Directive, SMLoc Loc) {
@@ -487,15 +522,18 @@ bool COFFMasmParser::parseDirectiveEndProc(StringRef Directive, SMLoc Loc) {
if (CurrentProcedures.empty())
return Error(Loc, "endp outside of procedure block");
- else if (!CurrentProcedures.back().equals_insensitive(Label))
+ else if (!CurrentProcedures.back().Name.equals_insensitive(Label))
return Error(LabelLoc, "endp does not match current procedure '" +
- CurrentProcedures.back() + "'");
+ CurrentProcedures.back().Name + "'");
- if (CurrentProceduresFramed.back()) {
+ if (CurrentProcedures.back().IsFramed) {
getStreamer().emitWinCFIEndProc(Loc);
}
CurrentProcedures.pop_back();
- CurrentProceduresFramed.pop_back();
+ cast<MCMasmParser>(getParser())
+ .setDefaultRetIsFar(!CurrentProcedures.empty() &&
+ CurrentProcedures.back().Distance ==
+ PROC_DISTANCE_FAR);
return false;
}
diff --git a/llvm/lib/MC/MCParser/MasmParser.cpp b/llvm/lib/MC/MCParser/MasmParser.cpp
index 51ac19c623732..2e3d3d3890add 100644
--- a/llvm/lib/MC/MCParser/MasmParser.cpp
+++ b/llvm/lib/MC/MCParser/MasmParser.cpp
@@ -36,6 +36,7 @@
#include "llvm/MC/MCParser/MCAsmLexer.h"
#include "llvm/MC/MCParser/MCAsmParser.h"
#include "llvm/MC/MCParser/MCAsmParserExtension.h"
+#include "llvm/MC/MCParser/MCMasmParser.h"
#include "llvm/MC/MCParser/MCParsedAsmOperand.h"
#include "llvm/MC/MCParser/MCTargetAsmParser.h"
#include "llvm/MC/MCRegisterInfo.h"
@@ -65,6 +66,7 @@
#include <memory>
#include <optional>
#include <sstream>
+#include <stdbool.h>
#include <string>
#include <tuple>
#include <utility>
@@ -373,7 +375,7 @@ FieldInitializer &FieldInitializer::operator=(FieldInitializer &&Initializer) {
/// The concrete assembly parser instance.
// Note that this is a full MCAsmParser, not an MCAsmParserExtension!
// It's a peer of AsmParser, not of COFFAsmParser, WasmAsmParser, etc.
-class MasmParser : public MCAsmParser {
+class MasmParser : public MCMasmParser {
private:
SourceMgr::DiagHandlerTy SavedDiagHandler;
void *SavedDiagContext;
@@ -448,6 +450,9 @@ class MasmParser : public MCAsmParser {
/// Are we parsing ms-style inline assembly?
bool ParsingMSInlineAsm = false;
+ /// Is the current default `ret` instruction far?
+ bool DefaultRetIsFar = false;
+
// Current <...> expression depth.
unsigned AngleBracketDepth = 0U;
@@ -473,6 +478,14 @@ class MasmParser : public MCAsmParser {
DirectiveKindMap[Directive] = DirectiveKindMap[Alias];
}
+ /// @name MCMasmParser Interface
+ /// {
+
+ bool getDefaultRetIsFar() const override { return DefaultRetIsFar; }
+ void setDefaultRetIsFar(bool IsFar) override { DefaultRetIsFar = IsFar; }
+
+ /// }
+
/// @name MCAsmParser Interface
/// {
@@ -504,8 +517,6 @@ class MasmParser : public MCAsmParser {
}
bool isParsingMSInlineAsm() override { return ParsingMSInlineAsm; }
- bool isParsingMasm() const override { return true; }
-
bool defineMacro(StringRef Name, StringRef Value) override;
bool lookUpField(StringRef Name, AsmFieldInfo &Info) const override;
diff --git a/llvm/lib/Target/X86/AsmParser/X86AsmParser.cpp b/llvm/lib/Target/X86/AsmParser/X86AsmParser.cpp
index 8221679f1969c..3c52997d08c7e 100644
--- a/llvm/lib/Target/X86/AsmParser/X86AsmParser.cpp
+++ b/llvm/lib/Target/X86/AsmParser/X86AsmParser.cpp
@@ -25,6 +25,7 @@
#include "llvm/MC/MCInstrInfo.h"
#include "llvm/MC/MCParser/MCAsmLexer.h"
#include "llvm/MC/MCParser/MCAsmParser.h"
+#include "llvm/MC/MCParser/MCMasmParser.h"
#include "llvm/MC/MCParser/MCParsedAsmOperand.h"
#include "llvm/MC/MCParser/MCTargetAsmParser.h"
#include "llvm/MC/MCRegisterInfo.h"
@@ -32,6 +33,7 @@
#include "llvm/MC/MCStreamer.h"
#include "llvm/MC/MCSubtargetInfo.h"
#include "llvm/MC/MCSymbol.h"
+#include "llvm/MC/MCSymbolCOFF.h"
#include "llvm/MC/TargetRegistry.h"
#include "llvm/Support/CommandLine.h"
#include "llvm/Support/Compiler.h"
@@ -1200,6 +1202,10 @@ class X86AsmParser : public MCTargetAsmParser {
void MatchFPUWaitAlias(SMLoc IDLoc, X86Operand &Op, OperandVector &Operands,
MCStreamer &Out, bool MatchingInlineAsm);
+ void MatchMASMFarCallToNear(SMLoc IDLoc, X86Operand &Op,
+ OperandVector &Operands, MCStreamer &Out,
+ bool MatchingInlineAsm);
+
bool ErrorMissingFeature(SMLoc IDLoc, const FeatureBitset &MissingFeatures,
bool MatchingInlineAsm);
@@ -2738,11 +2744,11 @@ bool X86AsmParser::parseIntelOperand(OperandVector &Operands, StringRef Name) {
if ((BaseReg || IndexReg || RegNo || DefaultBaseReg))
Operands.push_back(X86Operand::CreateMem(
getPointerWidth(), RegNo, Disp, BaseReg, IndexReg, Scale, Start, End,
- Size, DefaultBaseReg, /*SymName=*/StringRef(), /*OpDecl=*/nullptr,
+ Size, DefaultBaseReg, /*SymName=*/SM.getSymName(), /*OpDecl=*/nullptr,
/*FrontendSize=*/0, /*UseUpRegs=*/false, MaybeDirectBranchDest));
else
Operands.push_back(X86Operand::CreateMem(
- getPointerWidth(), Disp, Start, End, Size, /*SymName=*/StringRef(),
+ getPointerWidth(), Disp, Start, End, Size, /*SymName=*/SM.getSymName(),
/*OpDecl=*/nullptr, /*FrontendSize=*/0, /*UseUpRegs=*/false,
MaybeDirectBranchDest));
return false;
@@ -3440,6 +3446,14 @@ bool X86AsmParser::parseInstruction(ParseInstructionInfo &Info, StringRef Name,
}
}
+ if (Parser.isParsingMasm() && !is64BitMode()) {
+ // MASM implicitly converts "ret" to "retf" in far procedures; this is
+ // reflected in the default return type in the MCContext.
+ if (PatchedName == "ret" &&
+ cast<MCMasmParser>(getParser()).getDefaultRetIsFar())
+ PatchedName = "retf";
+ }
+
// Determine whether this is an instruction prefix.
// FIXME:
// Enhance prefixes integrity robustness. for example, following forms
@@ -4128,6 +4142,11 @@ bool X86AsmParser::matchAndEmitInstruction(SMLoc IDLoc, unsigned &Opcode,
// First, handle aliases that expand to multiple instructions.
MatchFPUWaitAlias(IDLoc, static_cast<X86Operand &>(*Operands[0]), Operands,
Out, MatchingInlineAsm);
+ if (getParser().isParsingMasm() && !is64BitMode()) {
+ MatchMASMFarCallToNear(IDLoc, static_cast<X86Operand &>(*Operands[0]),
+ Operands, Out, MatchingInlineAsm);
+ }
+
unsigned Prefixes = getPrefixes(Operands);
MCInst Inst;
@@ -4189,6 +4208,37 @@ void X86AsmParser::MatchFPUWaitAlias(SMLoc IDLoc, X86Operand &Op,
}
}
+void X86AsmParser::MatchMASMFarCallToNear(SMLoc IDLoc, X86Operand &Op,
+ OperandVector &Operands,
+ MCStreamer &Out,
+ bool MatchingInlineAsm) {
+ // FIXME: This should be replaced with a real .td file alias mechanism.
+ // Also, MatchInstructionImpl should actually *do* the EmitInstruction
+ // call.
+ if (Op.getToken() != "call")
+ return;
+ // This is a call instruction...
+
+ X86Operand &Operand = static_cast<X86Operand &>(*Operands[1]);
+ MCSymbol *Sym = getContext().lookupSymbol(Operand.getSymName());
+ if (Sym == nullptr || !Sym->isInSection() || !Sym->isCOFF() ||
+ !dyn_cast<MCSymbolCOFF>(Sym)->isFarProc())
+ return;
+ // Sym is a reference to a far proc in a code section....
+
+ if (Out.getCurrentSectionOnly() == &Sym->getSection()) {
+ // This is a call to a symbol declared as a far proc, and will be emitted as
+ // a near call... so we need to explicitly push the code section register
+ // before the call.
+ MCInst Inst;
+ Inst.setOpcode(X86::PUSH32r);
+ Inst.addOperand(MCOperand::createReg(MCRegister(X86::CS)));
+ Inst.setLoc(IDLoc);
+ if (!MatchingInlineAsm)
+ emitInstruction(Inst, Operands, Out);
+ }
+}
+
bool X86AsmParser::ErrorMissingFeature(SMLoc IDLoc,
const FeatureBitset &MissingFeatures,
bool MatchingInlineAsm) {
diff --git a/llvm/test/tools/llvm-ml/proc_distance.asm b/llvm/test/tools/llvm-ml/proc_distance.asm
new file mode 100644
index 0000000000000..71db903640b42
--- /dev/null
+++ b/llvm/test/tools/llvm-ml/proc_distance.asm
@@ -0,0 +1,56 @@
+; RUN: llvm-ml -m32 -filetype=s %s /Fo - | FileCheck %s
+
+.code
+
+DefaultProc PROC
+ ret
+DefaultProc ENDP
+; CHECK: DefaultProc:
+; CHECK: {{^ *}}ret{{ *$}}
+
+t1:
+call DefaultProc
+; CHECK: t1:
+; CHECK-NEXT: call DefaultProc
+
+NearProc PROC NEAR
+ ret
+NearProc ENDP
+; CHECK: NearProc:
+; CHECK: {{^ *}}ret{{ *$}}
+
+t2:
+call NearProc
+; CHECK: t2:
+; CHECK-NEXT: call NearProc
+
+FarProcInCode PROC FAR
+ ret
+FarProcInCode ENDP
+; CHECK: FarProcInCode:
+; CHECK: {{^ *}}retf{{ *$}}
+
+t3:
+call FarProcInCode
+; CHECK: t3:
+; CHECK-NEXT: push cs
+; CHECK-NEXT: call FarProcInCode
+
+FarCode SEGMENT SHARED NOPAGE NOCACHE INFO READ WRITE EXECUTE DISCARD
+
+FarProcInFarCode PROC FAR
+ ret
+FarProcInFarCode ENDP
+; CHECK: FarProcInFarCode:
+; CHECK: {{^ *}}retf{{ *$}}
+
+FarCode ENDS
+
+.code
+
+t4:
+call FarProcInFarCode
+; CHECK: t4:
+; CHECK-NEXT: call FarProcInFarCode
+
+END
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