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Crash fixes and small improvements to inline asm. (#1756)

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* codegen: LLVMConstInlineAsm is deprecated.

* codegen: replace commas in asm constraint strings by pipes as required by LLVM.

* ir: enforce usage of '=' constraint modifier for inline assembly outputs.

Others are not currently supported and this was just asserted alter in `ir_render_asm`.

* asm: forbid comptime_int/floats as inputs in favor of explicitely sized constants.

Fixes a crash due to comptime_int/floats having no type_ref.

* asm: handle inputs with integers of <8 or non power of 2 bitsize.

We widen them to the next highest power of two.
This commit is contained in:
Sahnvour
2018-11-19 22:22:21 +01:00
committed by Andrew Kelley
parent 89e82281be
commit 703c6684d1
6 changed files with 121 additions and 6 deletions
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31
src/codegen.cpp
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@@ -3660,6 +3660,13 @@ static LLVMValueRef ir_render_asm(CodeGen *g, IrExecutable *executable, IrInstru
AsmOutput *asm_output = asm_expr->output_list.at(i);
bool is_return = (asm_output->return_type != nullptr);
assert(*buf_ptr(asm_output->constraint) == '=');
// LLVM uses commas internally to separate different constraints,
// alternative constraints are achieved with pipes.
// We still allow the user to use commas in a way that is similar
// to GCC's inline assembly.
// http://llvm.org/docs/LangRef.html#constraint-codes
buf_replace(asm_output->constraint, ',', '|');
if (is_return) {
buf_appendf(&constraint_buf, "=%s", buf_ptr(asm_output->constraint) + 1);
} else {
@@ -3679,14 +3686,30 @@ static LLVMValueRef ir_render_asm(CodeGen *g, IrExecutable *executable, IrInstru
}
for (size_t i = 0; i < asm_expr->input_list.length; i += 1, total_index += 1, param_index += 1) {
AsmInput *asm_input = asm_expr->input_list.at(i);
buf_replace(asm_input->constraint, ',', '|');
IrInstruction *ir_input = instruction->input_list[i];
buf_append_buf(&constraint_buf, asm_input->constraint);
if (total_index + 1 < total_constraint_count) {
buf_append_char(&constraint_buf, ',');
}
param_types[param_index] = ir_input->value.type->type_ref;
param_values[param_index] = ir_llvm_value(g, ir_input);
ZigType *const type = ir_input->value.type;
LLVMTypeRef type_ref = type->type_ref;
LLVMValueRef value_ref = ir_llvm_value(g, ir_input);
// Handle integers of non pot bitsize by widening them.
if (type->id == ZigTypeIdInt) {
const size_t bitsize = type->data.integral.bit_count;
if (bitsize < 8 || !is_power_of_2(bitsize)) {
const bool is_signed = type->data.integral.is_signed;
const size_t wider_bitsize = bitsize < 8 ? 8 : round_to_next_power_of_2(bitsize);
ZigType *const wider_type = get_int_type(g, is_signed, wider_bitsize);
type_ref = wider_type->type_ref;
value_ref = gen_widen_or_shorten(g, false, type, wider_type, value_ref);
}
}
param_types[param_index] = type_ref;
param_values[param_index] = value_ref;
}
for (size_t i = 0; i < asm_expr->clobber_list.length; i += 1, total_index += 1) {
Buf *clobber_buf = asm_expr->clobber_list.at(i);
@@ -3705,8 +3728,8 @@ static LLVMValueRef ir_render_asm(CodeGen *g, IrExecutable *executable, IrInstru
LLVMTypeRef function_type = LLVMFunctionType(ret_type, param_types, (unsigned)input_and_output_count, false);
bool is_volatile = asm_expr->is_volatile || (asm_expr->output_list.length == 0);
LLVMValueRef asm_fn = LLVMConstInlineAsm(function_type, buf_ptr(&llvm_template),
buf_ptr(&constraint_buf), is_volatile, false);
LLVMValueRef asm_fn = LLVMGetInlineAsm(function_type, buf_ptr(&llvm_template), buf_len(&llvm_template),
buf_ptr(&constraint_buf), buf_len(&constraint_buf), is_volatile, false, LLVMInlineAsmDialectATT);
return LLVMBuildCall(g->builder, asm_fn, param_values, (unsigned)input_and_output_count, "");
}