compilers/clike: Speedup cross_compute_int

Expand the expression passed into cross_compute_int using the
preprocessor first and then try to evaluate the expanded expression
using the host machine compiler and test if the result is valid.

Co-authored-by: Charles Brunet <charles.brunet@optelgroup.com>

1 files changed, 15 insertions, 0 deletions

diff --git a/mesonbuild/compilers/mixins/clike.py b/mesonbuild/compilers/mixins/clike.py
index a75cd2a81..19a6bb487 100644
--- a/mesonbuild/compilers/mixins/clike.py
+++ b/mesonbuild/compilers/mixins/clike.py
@@ -476,6 +476,21 @@ class CLikeCompiler(Compiler):
             if self._compile_int(f'{expression} == {guess}', prefix, env, extra_args, dependencies):
                 return guess
 
+        # Try to expand the expression and evaluate it on the build machines compiler
+        if self.language in env.coredata.compilers.build:
+            try:
+                expanded, _ = self.get_define(expression, prefix, env, extra_args, dependencies, False)
+                evaluate_expanded = f'''
+                #include <stdio.h>
+                #include <stdint.h>
+                int main(void) {{ int expression = {expanded}; printf("%d", expression); return 0; }}'''
+                run = env.coredata.compilers.build[self.language].run(evaluate_expanded, env)
+                if run and run.compiled and run.returncode == 0:
+                    if self._compile_int(f'{expression} == {run.stdout}', prefix, env, extra_args, dependencies):
+                        return int(run.stdout)
+            except mesonlib.EnvironmentException:
+                pass
+
         # If no bounds are given, compute them in the limit of int32
         maxint = 0x7fffffff
         minint = -0x80000000