Simplify LDMD quite a bit by translating the few different command-line
options directly in-place. This puts some more stress onto LDC's
command-line parsing, especially due to multiple occurrences of a single
Boolean option (e.g., '-o-') or mixtures of `-m64` and `-m32` etc. for
dmd-testsuite.
Also add new command-line option `-verrors-spec` showing gagged errors
(DMD's equivalent is `-verrors=<spec|limit>`) and sync the usage text with
DMD. LDMD now also recognizes `-h` (and `/?` on Windows).
The part needing most attention was ddmd.root.ctfloat, ddmd.target (incl.
gen/target.cpp) and ddmd.builtin. The front-end is now prepared for
elaborate compile-time floating-point types to allow for proper cross-
compilation.
This version still uses the host's `real` type for compile-time reals,
except for MSVC hosts, which still use 64-bit doubles (when compiled with
DMD host compiler too).
Some other changes:
* semantic*() of Statements extracted from statement.d to statementsem.d
* mangle() -> mangleToBuffer()
* Identifier::string -> toChars()
* Token::float80value => floatvalue
* Dsymbol::isAggregateMember() => isMember()
* BoolExp is no more
* ddmd.root.ctfloat: LDC-specific CTFE builtins
Introduce a hidden `-dwarf-version=<uint>` switch to support old gdb versions
used by Travis. Older versions only supporting DWARF-2 and/or not supporting
TLS correctly are detected in dmd-testsuite's CMakefile.
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.
There is a LLVM 3.7 command line option named color. This option is
only available if ldc is linked against shared LLVM libraries.
Because the LDC color option uses a FlagParser simple renaming does
not work. The solution is now:
- Rename LLVM option `color` to `llvm-color` and hide this option
- Dynamically create the LDC option `color`
This finally enables building with shared LLVM libraries.
