ldc/gen/asmstmt.cpp

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//===-- asmstmt.cpp -------------------------------------------------------===//
//
// LDC the LLVM D compiler
//
// This file originates from work by David Friedman for GDC released under
// the GPL 2 and Artistic licenses. See the LICENSE file for details.
//
//===----------------------------------------------------------------------===//
#include "dmd/declaration.h"
#include "dmd/dsymbol.h"
#include "dmd/errors.h"
#include "dmd/ldcbindings.h"
#include "dmd/scope.h"
#include "dmd/statement.h"
#include "gen/dvalue.h"
#include "gen/functions.h"
#include "gen/irstate.h"
#include "gen/llvm.h"
#include "gen/llvmhelpers.h"
#include "gen/logger.h"
#include "gen/tollvm.h"
#include "ir/irfunction.h"
#include "llvm/IR/InlineAsm.h"
#include <cassert>
#include <cstring>
#include <deque>
#include <string>
#include <sstream>
typedef enum {
Arg_Integer,
Arg_Pointer,
Arg_Memory,
Arg_FrameRelative,
Arg_LocalSize,
Arg_Dollar
} AsmArgType;
typedef enum { Mode_Input, Mode_Output, Mode_Update } AsmArgMode;
struct AsmArg {
Expression *expr;
AsmArgType type;
AsmArgMode mode;
AsmArg(AsmArgType type, Expression *expr, AsmArgMode mode) {
this->type = type;
this->expr = expr;
this->mode = mode;
}
};
struct AsmCode {
std::string insnTemplate;
std::vector<AsmArg> args;
std::vector<bool> regs;
unsigned dollarLabel;
int clobbersMemory;
explicit AsmCode(int n_regs) {
regs.resize(n_regs, false);
dollarLabel = 0;
clobbersMemory = 0;
}
};
struct AsmParserCommon {
virtual ~AsmParserCommon() = default;
virtual void run(Scope *sc, InlineAsmStatement *asmst) = 0;
virtual std::string getRegName(int i) = 0;
};
AsmParserCommon *asmparser = nullptr;
#include "asm-x86.h" // x86 assembly parser
#define ASM_X86_64
#include "asm-x86.h" // x86_64 assembly parser
#undef ASM_X86_64
using namespace dmd;
/**
* Replaces <<func>> with the name of the currently codegen'd function.
*
* This kludge is required to handle labels correctly, as the instruction
* strings for jumps, … are generated during semantic3, but attribute inference
* might change the function type (and hence the mangled name) right at the end
* of semantic3.
*/
static void replace_func_name(IRState *p, std::string &insnt) {
static const std::string needle("<<func>>");
const char *mangle = mangleExact(p->func()->decl);
size_t pos;
while (std::string::npos != (pos = insnt.find(needle))) {
// This will only happen for few instructions, and only once for those.
insnt.replace(pos, needle.size(), mangle);
}
}
Statement *asmSemantic(AsmStatement *s, Scope *sc) {
if (!s->tokens) {
return nullptr;
}
sc->func->hasReturnExp |= 8;
// GCC-style asm starts with a string literal or a `(`
if (s->tokens->value == TOK::string_ ||
s->tokens->value == TOK::leftParenthesis) {
auto gas = createGccAsmStatement(s->loc, s->tokens);
return gccAsmSemantic(gas, sc);
}
// this is DMD-style asm
sc->func->hasReturnExp |= 32;
const auto caseSensitive = s->caseSensitive;
auto ias = createInlineAsmStatement(s->loc, s->tokens);
s = ias;
s->caseSensitive = caseSensitive;
bool err = false;
llvm::Triple const &t = *global.params.targetTriple;
if (!(t.getArch() == llvm::Triple::x86 ||
t.getArch() == llvm::Triple::x86_64)) {
error(s->loc,
"DMD-style `asm { op; }` statements are not supported for the \"%s\" "
"architecture.",
t.getArchName().str().c_str());
errorSupplemental(s->loc, "Use GDC-style `asm { \"op\" : …; }` syntax or "
"`ldc.llvmasm.__asm` instead.");
err = true;
}
if (!global.params.useInlineAsm) {
error(s->loc,
"the `asm` statement is not allowed when the -noasm switch is used");
err = true;
}
if (err) {
if (!global.gag) {
fatal();
}
return s;
}
// puts(toChars());
if (!asmparser) {
if (t.getArch() == llvm::Triple::x86) {
asmparser = new AsmParserx8632::AsmParser;
} else if (t.getArch() == llvm::Triple::x86_64) {
asmparser = new AsmParserx8664::AsmParser;
}
}
asmparser->run(sc, ias);
return s;
}
void AsmStatement_toIR(InlineAsmStatement *stmt, IRState *irs) {
IF_LOG Logger::println("InlineAsmStatement::toIR(): %s", stmt->loc.toChars());
LOG_SCOPE;
// sanity check
assert((irs->func()->decl->hasReturnExp & 40) == 40);
// get asm block
IRAsmBlock *asmblock = irs->asmBlock;
assert(asmblock);
// debug info
gIR->DBuilder.EmitStopPoint(stmt->loc);
if (!stmt->asmcode) {
return;
}
static std::string i_cns = "i";
static std::string p_cns = "i";
static std::string m_cns = "*m";
static std::string mw_cns = "=*m";
static std::string mrw_cns = "+*m";
static std::string memory_name = "memory";
AsmCode *code = static_cast<AsmCode *>(stmt->asmcode);
auto asmStmt = new IRAsmStmt;
asmStmt->isBranchToLabel = stmt->isBranchToLabel;
std::vector<std::string> input_constraints;
std::vector<std::string> output_constraints;
std::vector<std::string> clobbers;
// FIXME
//#define HOST_WIDE_INT long
// HOST_WIDE_INT var_frame_offset; // "frame_offset" is a macro
bool clobbers_mem = code->clobbersMemory;
int input_idx = 0;
int n_outputs = 0;
int arg_map[10];
assert(code->args.size() <= 10);
auto arg = code->args.begin();
for (unsigned i = 0; i < code->args.size(); i++, ++arg) {
bool is_input = true;
LLValue *arg_val = nullptr;
std::string cns;
switch (arg->type) {
case Arg_Integer:
arg_val = DtoRVal(arg->expr);
do_integer:
cns = i_cns;
break;
case Arg_Pointer:
assert(arg->expr->isVarExp());
arg_val = DtoRVal(arg->expr);
cns = p_cns;
break;
case Arg_Memory:
arg_val = DtoRVal(arg->expr);
switch (arg->mode) {
case Mode_Input:
cns = m_cns;
break;
case Mode_Output:
cns = mw_cns;
is_input = false;
break;
case Mode_Update:
cns = mrw_cns;
is_input = false;
break;
}
break;
case Arg_FrameRelative:
// FIXME
llvm_unreachable("Arg_FrameRelative not supported.");
/* if (auto ve = arg->expr->isVarExp())
arg_val = ve->var->toSymbol()->Stree;
else
assert(0);
if ( getFrameRelativeValue(arg_val, & var_frame_offset) ) {
// arg_val = irs->integerConstant(var_frame_offset);
cns = i_cns;
} else {
error(stmt->loc, "argument not frame relative");
return;
}
if (arg->mode != Mode_Input)
clobbers_mem = true;
break;*/
case Arg_LocalSize:
// FIXME
llvm_unreachable("Arg_LocalSize not supported.");
/* var_frame_offset = cfun->x_frame_offset;
if (var_frame_offset < 0)
var_frame_offset = - var_frame_offset;
arg_val = irs->integerConstant( var_frame_offset );*/
goto do_integer;
default:
llvm_unreachable("Unknown inline asm reference type.");
}
if (is_input) {
arg_map[i] = --input_idx;
asmStmt->in.ops.push_back(arg_val);
input_constraints.push_back(cns);
asmStmt->in.dTypes.push_back(arg->expr->type);
} else {
arg_map[i] = n_outputs++;
asmStmt->out.ops.push_back(arg_val);
output_constraints.push_back(cns);
asmStmt->out.dTypes.push_back(arg->expr->type);
}
}
// Telling GCC that callee-saved registers are clobbered makes it preserve
// those registers. This changes the stack from what a naked function
// expects.
// FIXME
// if (!irs->func->isNaked()) {
assert(asmparser);
for (size_t i = 0; i < code->regs.size(); i++) {
if (code->regs[i]) {
clobbers.push_back(asmparser->getRegName(i));
}
}
if (clobbers_mem) {
clobbers.push_back(memory_name);
}
// }
// Remap argument numbers
for (unsigned i = 0; i < code->args.size(); i++) {
if (arg_map[i] < 0) {
arg_map[i] = -arg_map[i] - 1 + n_outputs;
}
}
bool pct = false;
auto p = code->insnTemplate.begin();
auto q = code->insnTemplate.end();
// printf("start: %.*s\n", code->insnTemplateLen, code->insnTemplate);
while (p < q) {
if (pct) {
if (*p >= '0' && *p <= '9') {
// %% doesn't check against nargs
*p = '0' + arg_map[*p - '0'];
pct = false;
} else if (*p == '$') {
pct = false;
}
// assert(*p == '%');// could be 'a', etc. so forget it..
} else if (*p == '$') {
pct = true;
}
++p;
}
IF_LOG {
Logger::cout() << "final asm: " << code->insnTemplate << '\n';
std::ostringstream ss;
ss << "GCC-style output constraints: {";
for (const auto &oc : output_constraints) {
ss << " " << oc;
}
ss << " }";
Logger::println("%s", ss.str().c_str());
ss.str("");
ss << "GCC-style input constraints: {";
for (const auto &ic : input_constraints) {
ss << " " << ic;
}
ss << " }";
Logger::println("%s", ss.str().c_str());
ss.str("");
ss << "GCC-style clobbers: {";
for (const auto &c : clobbers) {
ss << " " << c;
}
ss << " }";
Logger::println("%s", ss.str().c_str());
}
// rewrite GCC-style constraints to LLVM-style constraints
int n = 0;
for (auto &oc : output_constraints) {
// rewrite update constraint to in and out constraints
if (oc[0] == '+') {
assert(oc == mrw_cns && "What else are we updating except memory?");
/* LLVM doesn't support updating operands, so split into an input
* and an output operand.
*/
// Change update operand to pure output operand.
oc = mw_cns;
// Add input operand with same value, with original as "matching
// output".
std::ostringstream ss;
ss << '*' << (n + asmblock->outputcount);
// Must be at the back; unused operands before used ones screw up
// numbering.
input_constraints.push_back(ss.str());
asmStmt->in.ops.push_back(asmStmt->out.ops[n]);
asmStmt->in.dTypes.push_back(asmStmt->out.dTypes[n]);
}
asmStmt->out.c += oc;
asmStmt->out.c += ",";
n++;
}
asmblock->outputcount += n;
for (const auto &ic : input_constraints) {
asmStmt->in.c += ic;
asmStmt->in.c += ",";
}
std::string clobstr;
for (const auto &c : clobbers) {
clobstr = "~{" + c + "},";
asmblock->clobs.insert(clobstr);
}
IF_LOG {
{
Logger::println("Output values:");
LOG_SCOPE
size_t i = 0;
for (auto ov : asmStmt->out.ops) {
Logger::cout() << "Out " << i++ << " = " << *ov << '\n';
}
}
{
Logger::println("Input values:");
LOG_SCOPE
size_t i = 0;
for (auto iv : asmStmt->in.ops) {
Logger::cout() << "In " << i++ << " = " << *iv << '\n';
}
}
}
// excessive commas are removed later...
replace_func_name(irs, code->insnTemplate);
// push asm statement
asmStmt->code = code->insnTemplate;
asmblock->s.push_back(asmStmt);
}
//////////////////////////////////////////////////////////////////////////////
// rewrite argument indices to the block scope indices
static void remap_args(std::string &insnt, size_t nargs, size_t idx,
const std::string& prefix) {
static const std::string digits[10] = {"0", "1", "2", "3", "4",
"5", "6", "7", "8", "9"};
assert(nargs <= 10);
static const std::string suffix(">>");
std::string argnum;
std::string needle;
char buf[10];
for (unsigned i = 0; i < nargs; i++) {
needle = prefix + digits[i] + suffix;
size_t pos = insnt.find(needle);
if (std::string::npos != pos) {
snprintf(buf, 10, "%llu", static_cast<unsigned long long>(idx++));
}
while (std::string::npos != (pos = insnt.find(needle))) {
insnt.replace(pos, needle.size(), buf);
}
}
}
void CompoundAsmStatement_toIR(CompoundAsmStatement *stmt, IRState *p) {
IF_LOG Logger::println("CompoundAsmStatement::toIR(): %s",
stmt->loc.toChars());
LOG_SCOPE;
const bool isCompoundGccAsmStatement =
(stmt->statements && stmt->statements->length &&
stmt->statements->front()->isGccAsmStatement());
if (isCompoundGccAsmStatement) {
for (Statement *s : *stmt->statements) {
if (auto gas = s->isGccAsmStatement()) {
Statement_toIR(gas, p);
} else {
error(s->loc,
"DMD-style assembly statement unsupported within GCC-style "
"`asm` block");
fatal();
}
}
return;
}
// disable inlining by default
if (!p->func()->decl->allowInlining) {
p->func()->setNeverInline();
}
// create asm block structure
assert(!p->asmBlock);
auto asmblock = new IRAsmBlock(stmt);
assert(asmblock);
p->asmBlock = asmblock;
// do asm statements
for (Statement *s : *stmt->statements) {
if (s) {
if (s->isGccAsmStatement()) {
error(s->loc,
"GCC-style assembly statement unsupported within DMD-style "
"`asm` block");
fatal();
}
Statement_toIR(s, p);
}
}
// build forwarder for in-asm branches to external labels
// this additional asm code sets the __llvm_jump_target variable
// to a unique value that will identify the jump target in
// a post-asm switch
// maps each goto destination to its special value
std::map<LabelDsymbol *, int> gotoToVal;
// location of the special value determining the goto label
// will be set if post-asm dispatcher block is needed
LLValue *jump_target = nullptr;
{
FuncDeclaration *fd = gIR->func()->decl;
const char *fdmangle = mangleExact(fd);
// we use a simple static counter to make sure the new end labels are
// unique
static size_t uniqueLabelsId = 0;
std::ostringstream asmGotoEndLabel;
printLabelName(asmGotoEndLabel, fdmangle, "_llvm_asm_end");
asmGotoEndLabel << uniqueLabelsId++;
// initialize the setter statement we're going to build
auto outSetterStmt = new IRAsmStmt;
std::string asmGotoEnd = "\n\tjmp " + asmGotoEndLabel.str() + "\n";
std::ostringstream code;
code << asmGotoEnd;
int n_goto = 1;
for (IRAsmStmt *a : asmblock->s) {
// skip non-branch statements
LabelDsymbol *const targetLabel = a->isBranchToLabel;
if (!targetLabel) {
continue;
}
Identifier *const ident = targetLabel->ident;
// if internal, no special handling is necessary, skip
if (llvm::any_of(asmblock->internalLabels,
[ident](Identifier *i) { return i->equals(ident); })) {
continue;
}
// if we already set things up for this branch target, skip
if (gotoToVal.find(targetLabel) != gotoToVal.end()) {
continue;
}
// record that the jump needs to be handled in the post-asm dispatcher
gotoToVal[targetLabel] = n_goto;
// provide an in-asm target for the branch and set value
IF_LOG Logger::println(
"statement '%s' references outer label '%s': creating forwarder",
a->code.c_str(), ident->toChars());
printLabelName(code, fdmangle, ident->toChars());
code << ":\n\t";
code << "movl $<<in" << n_goto << ">>, $<<out0>>\n";
// FIXME: Store the value -> label mapping somewhere, so it can be
// referenced later
outSetterStmt->in.ops.push_back(DtoConstUint(n_goto));
outSetterStmt->in.dTypes.push_back(Type::tuns32);
outSetterStmt->in.c += "i,";
code << asmGotoEnd;
++n_goto;
}
if (code.str() != asmGotoEnd) {
// finalize code
outSetterStmt->code = code.str();
outSetterStmt->code += asmGotoEndLabel.str() + ":\n";
// create storage for and initialize the temporary
jump_target = DtoAllocaDump(DtoConstUint(0), 0, "__llvm_jump_target");
// setup variable for output from asm
outSetterStmt->out.c = "=*m,";
outSetterStmt->out.ops.push_back(jump_target);
outSetterStmt->out.dTypes.push_back(Type::tuns32);
asmblock->s.push_back(outSetterStmt);
} else {
delete outSetterStmt;
}
}
// build a fall-off-end-properly asm statement
FuncDeclaration *thisfunc = p->func()->decl;
bool useabiret = false;
p->asmBlock->asmBlock->abiret = nullptr;
if (thisfunc->fbody->endsWithAsm() == stmt &&
thisfunc->type->nextOf()->ty != TY::Tvoid) {
// there can't be goto forwarders in this case
assert(gotoToVal.empty());
emitABIReturnAsmStmt(asmblock, stmt->loc, thisfunc);
useabiret = true;
}
// build asm block
struct ArgBlock {
ArgBlock() = default;
std::vector<LLValue *> args;
std::vector<LLType *> types;
std::vector<Type *> dTypes;
std::string c;
} in, out;
std::string clobbers;
std::string code;
size_t asmIdx = asmblock->retn;
Logger::println("do outputs");
size_t n = asmblock->s.size();
for (size_t i = 0; i < n; ++i) {
IRAsmStmt *a = asmblock->s[i];
assert(a);
size_t onn = a->out.ops.size();
for (size_t j = 0; j < onn; ++j) {
out.args.push_back(a->out.ops[j]);
out.types.push_back(a->out.ops[j]->getType());
out.dTypes.push_back(a->out.dTypes[j]);
}
if (!a->out.c.empty()) {
out.c += a->out.c;
}
remap_args(a->code, onn + a->in.ops.size(), asmIdx, "<<out");
asmIdx += onn;
}
Logger::println("do inputs");
for (size_t i = 0; i < n; ++i) {
IRAsmStmt *a = asmblock->s[i];
assert(a);
size_t inn = a->in.ops.size();
for (size_t j = 0; j < inn; ++j) {
in.args.push_back(a->in.ops[j]);
in.types.push_back(a->in.ops[j]->getType());
in.dTypes.push_back(a->in.dTypes[j]);
}
if (!a->in.c.empty()) {
in.c += a->in.c;
}
remap_args(a->code, inn + a->out.ops.size(), asmIdx, "<<in");
asmIdx += inn;
if (!code.empty()) {
code += "\n\t";
}
code += a->code;
}
asmblock->s.clear();
// append inputs
out.c += in.c;
// append clobbers
for (const auto &c : asmblock->clobs) {
out.c += c;
}
// remove excessive comma
if (!out.c.empty()) {
out.c.resize(out.c.size() - 1);
}
IF_LOG {
Logger::println("code = \"%s\"", code.c_str());
Logger::println("constraints = \"%s\"", out.c.c_str());
}
// build return types
LLType *retty;
if (asmblock->retn) {
retty = asmblock->retty;
} else {
retty = llvm::Type::getVoidTy(gIR->context());
}
// build argument types
std::vector<LLType *> types;
types.insert(types.end(), out.types.begin(), out.types.end());
types.insert(types.end(), in.types.begin(), in.types.end());
llvm::FunctionType *fty = llvm::FunctionType::get(retty, types, false);
IF_LOG Logger::cout() << "function type = " << *fty << '\n';
std::vector<LLValue *> args;
args.insert(args.end(), out.args.begin(), out.args.end());
args.insert(args.end(), in.args.begin(), in.args.end());
auto constraintInfo = llvm::InlineAsm::ParseConstraints(out.c);
assert(constraintInfo.size() >= out.dTypes.size() + in.dTypes.size());
std::vector<LLType *> indirectTypes;
indirectTypes.reserve(out.dTypes.size() + in.dTypes.size());
size_t i = asmblock->retn;
for (Type *t : out.dTypes) {
assert(constraintInfo[i].Type == llvm::InlineAsm::ConstraintPrefix::isOutput);
if (constraintInfo[i].isIndirect) {
if (TypePointer *pt = t->isTypePointer())
indirectTypes.push_back(DtoMemType(pt->nextOf()));
else
indirectTypes.push_back(DtoMemType(t));
}
i++;
}
for (Type *t : in.dTypes) {
assert(constraintInfo[i].Type == llvm::InlineAsm::ConstraintPrefix::isInput);
if (constraintInfo[i].isIndirect) {
if (TypePointer *pt = t->isTypePointer())
indirectTypes.push_back(DtoType(pt->nextOf()));
else
indirectTypes.push_back(DtoType(t));
}
i++;
}
IF_LOG {
Logger::cout() << "Arguments:" << '\n';
Logger::indent();
size_t i = 0;
for (auto arg : args) {
Stream cout = Logger::cout();
cout << '$' << i << " ==> " << *arg;
if (!llvm::isa<llvm::Instruction>(arg) &&
!llvm::isa<LLGlobalValue>(arg)) {
cout << '\n';
}
++i;
}
Logger::undent();
}
for (; i < constraintInfo.size(); i++) {
if (!constraintInfo[i].isIndirect)
continue;
llvm::errs() << "unhandled indirect constraint in" << out.c << "\nindex i = " << i << '\n';
llvm::errs() << "function type = " << *fty << '\n';
for (size_t j = 0; j < indirectTypes.size(); j++) {
llvm::errs() << " " << *(indirectTypes[j]) << '\n';
}
llvm_unreachable("unhandled indirect constraint");
}
llvm::InlineAsm *ia = llvm::InlineAsm::get(fty, code, out.c, true);
auto call = p->createInlineAsmCall(stmt->loc, ia, args, indirectTypes);
if (!retty->isVoidTy()) {
call->setName("asm");
}
IF_LOG Logger::cout() << "Complete asm statement: " << *call << '\n';
// capture abi return value
if (useabiret) {
IRAsmBlock *block = p->asmBlock;
if (block->retfixup) {
block->asmBlock->abiret = (*block->retfixup)(p->ir, call);
} else if (p->asmBlock->retemu) {
block->asmBlock->abiret = DtoLoad(block->retty, block->asmBlock->abiret);
} else {
block->asmBlock->abiret = call;
}
}
p->asmBlock = nullptr;
// if asm contained external branches, emit goto forwarder code
if (!gotoToVal.empty()) {
assert(jump_target);
// make new blocks
llvm::BasicBlock *bb = p->insertBB("afterasmgotoforwarder");
auto val = DtoLoad(LLType::getInt32Ty(gIR->context()), jump_target, "__llvm_jump_target_value");
llvm::SwitchInst *sw = p->ir->CreateSwitch(val, bb, gotoToVal.size());
// add all cases
for (const auto &pair : gotoToVal) {
llvm::BasicBlock *casebb = p->insertBBBefore(bb, "case");
sw->addCase(LLConstantInt::get(llvm::IntegerType::get(gIR->context(), 32),
pair.second),
casebb);
p->ir->SetInsertPoint(casebb);
DtoGoto(stmt->loc, pair.first);
}
p->ir->SetInsertPoint(bb);
}
}
//////////////////////////////////////////////////////////////////////////////
void AsmStatement_toNakedIR(InlineAsmStatement *stmt, IRState *irs) {
IF_LOG Logger::println("InlineAsmStatement::toNakedIR(): %s",
stmt->loc.toChars());
LOG_SCOPE;
// is there code?
if (!stmt->asmcode) {
return;
}
AsmCode *code = static_cast<AsmCode *>(stmt->asmcode);
// build asm stmt
replace_func_name(irs, code->insnTemplate);
irs->nakedAsm << "\t" << code->insnTemplate << std::endl;
}