Add the commandline options -fprofile-instr-generate[=filename] and -profile-instr-use=filename
-fprofile-instr-generate
-- Add instrumentation on branches, switches, and function entry; uses LLVM's InstrProf pass.
-- Link to profile runtime that writes instrumentation counters to a file.
-fprofile-instr-use
-- Read profile data from a file and apply branch weights to branches and switches, and annotate functions with entrycount in LLVM IR.
-- Functions with low or high entrycount are marked with 'cold' or 'inlinehint'.
The only statement type without PGO yet is "try-finally".
A new pragma, `pragma(LDC_profile_instr, [ true | false ])`, is added to selectively disable/enable instrumentation of functions (granularity = whole functions).
The runtime library ldc-profile-rt is a copy of LLVM compiler-rt lib/profile. It has to be exactly in-sync with the LLVM version, and thus we need a copy for each PGO-supported LLVM (>=3.7).
import ldc.profile for a D interface to ldc-profile-rt (for example to reset execution counts after a program startup phase).
The instrumentation data is mainly passed on to LLVM: function-entry counts and branch counts/probabilities. LDC marks functions as hot when "execution count is 30% of the maximum function execution count", and marks functions as cold if their count is 1% of maximum function execution count.
The source of LLVM's llvm-profdata tool is hereby included in LDCs repository (different source for each LLVM version), and the binary is included in the install bin folder.
The executable is named "ldc-profdata" to avoid clashing with llvm-profdata on the same machine. This is needed because profdata executable has to be in-sync with the LLVM version used to build LDC.
Maintenance burden: for trunk LLVM, we have to keep ldc-profile-rt and llvm-profdata in sync. There is no diff with upstream; but because of active development there are the occasional API changes.
Also adds the CMake infrastructure to compile and link the D source files.
The build is partially broken:
- A few files in Phobos and druntime do not build
- MSVC build is broken because of unresolved symbols involving reals
1. Main include corresponding to .cpp file, if any.
2. DMD and LDC includes.
3. LLVM includes.
4. System includes.
Also updated a few include guards to match the default format.
DMD has the obscure functionality to install functions starting with
_STI_ as global ctors and funtions starting with _STD_ as global
dtors. IMHO a pragma is a better way to specify the behaviour.
This commit adds pragma(LDC_global_crt_ctor) and
pragma(LDC_global_crt_dtor). If the pragma is specified on a function
or static method then an entry is made in the corresponding list. E.g.
in monitor_.d:
extern (C) {
#pragma(LDC_global_crt_ctor)
void _STI_monitor_staticctor()
{
// ...
}
}
This works on Linux without problems. On Windows with MS C Runtime
ctors work always but dtors are invoked only if linked against the
static C runtime. Dtors on Windows require at least LLVM 3.2.
Adding pragma llvm_inline_ir.
Improved the error messages.
Append "ret void" when the return type is void
Improved the error message
in case when the string passed as llvm inline ir isn't valid llvm
assembly language.
LLVM 3.2 fix.
Add attribute AlwaysInline inside DtoInlineIRFunction.
Always generate a body for llvm_inline_ir
Also, always make llvm_inline_ir functions linkonce_odr. Because
the body is always generated when a module uses a llvm_inline_ir
function, the fact that the linker removes the function shouldn't
cause problems.
