对于像 C 这样相对简单(算法上)的语言，与解析/词法分析/语义分析相比，代码生成阶段花费了多少时间？我对更笼统的答案感兴趣，甚至对特定于实现的答案感兴趣。
最佳答案
您可以使用 GCC 通过 -fstats 发出统计信息。以下是 gcc4.5 生成的示例摘要:
Execution times (seconds)
callgraph construction: 0.05 ( 1%) usr 0.06 ( 2%) sys 0.14 ( 1%) wall 2885 kB ( 1%) ggc
callgraph optimization: 0.14 ( 2%) usr 0.05 ( 2%) sys 0.26 ( 2%) wall 4433 kB ( 1%) ggc
ipa cp : 0.02 ( 0%) usr 0.00 ( 0%) sys 0.02 ( 0%) wall 430 kB ( 0%) ggc
ipa reference : 0.01 ( 0%) usr 0.00 ( 0%) sys 0.02 ( 0%) wall 11 kB ( 0%) ggc
ipa pure const : 0.03 ( 0%) usr 0.01 ( 0%) sys 0.04 ( 0%) wall 31 kB ( 0%) ggc
ipa SRA : 0.02 ( 0%) usr 0.00 ( 0%) sys 0.08 ( 1%) wall 5280 kB ( 2%) ggc
cfg cleanup : 0.08 ( 1%) usr 0.02 ( 1%) sys 0.12 ( 1%) wall 102 kB ( 0%) ggc
trivially dead code : 0.03 ( 0%) usr 0.00 ( 0%) sys 0.05 ( 0%) wall 0 kB ( 0%) ggc
df multiple defs : 0.03 ( 0%) usr 0.00 ( 0%) sys 0.01 ( 0%) wall 0 kB ( 0%) ggc
df reaching defs : 0.04 ( 0%) usr 0.00 ( 0%) sys 0.00 ( 0%) wall 0 kB ( 0%) ggc
df live regs : 0.06 ( 1%) usr 0.01 ( 0%) sys 0.17 ( 1%) wall 0 kB ( 0%) ggc
df live&initialized regs: 0.05 ( 1%) usr 0.00 ( 0%) sys 0.08 ( 1%) wall 0 kB ( 0%) ggc
df use-def / def-use chains: 0.01 ( 0%) usr 0.00 ( 0%) sys 0.02 ( 0%) wall 0 kB ( 0%) ggc
df reg dead/unused notes: 0.08 ( 1%) usr 0.01 ( 0%) sys 0.08 ( 1%) wall 1165 kB ( 0%) ggc
register information : 0.02 ( 0%) usr 0.01 ( 0%) sys 0.03 ( 0%) wall 0 kB ( 0%) ggc
alias analysis : 0.07 ( 1%) usr 0.01 ( 0%) sys 0.06 ( 0%) wall 2993 kB ( 1%) ggc
alias stmt walking : 0.05 ( 1%) usr 0.02 ( 1%) sys 0.10 ( 1%) wall 5 kB ( 0%) ggc
register scan : 0.01 ( 0%) usr 0.00 ( 0%) sys 0.00 ( 0%) wall 10 kB ( 0%) ggc
rebuild jump labels : 0.02 ( 0%) usr 0.01 ( 0%) sys 0.05 ( 0%) wall 0 kB ( 0%) ggc
preprocessing : 0.16 ( 2%) usr 0.15 ( 6%) sys 0.34 ( 3%) wall 1508 kB ( 0%) ggc
parser : 0.99 (12%) usr 0.36 (14%) sys 1.24 (10%) wall 102915 kB (33%) ggc
name lookup : 0.50 ( 6%) usr 0.68 (26%) sys 1.25 (10%) wall 19025 kB ( 6%) ggc
inline heuristics : 0.10 ( 1%) usr 0.02 ( 1%) sys 0.13 ( 1%) wall 2310 kB ( 1%) ggc
integration : 0.24 ( 3%) usr 0.08 ( 3%) sys 0.29 ( 2%) wall 32982 kB (10%) ggc
tree gimplify : 0.12 ( 1%) usr 0.00 ( 0%) sys 0.06 ( 0%) wall 10967 kB ( 3%) ggc
tree eh : 0.02 ( 0%) usr 0.00 ( 0%) sys 0.02 ( 0%) wall 2932 kB ( 1%) ggc
tree CFG construction : 0.01 ( 0%) usr 0.00 ( 0%) sys 0.04 ( 0%) wall 6725 kB ( 2%) ggc
tree CFG cleanup : 0.15 ( 2%) usr 0.03 ( 1%) sys 0.15 ( 1%) wall 531 kB ( 0%) ggc
tree VRP : 0.11 ( 1%) usr 0.00 ( 0%) sys 0.12 ( 1%) wall 9477 kB ( 3%) ggc
tree copy propagation : 0.09 ( 1%) usr 0.01 ( 0%) sys 0.09 ( 1%) wall 2850 kB ( 1%) ggc
tree find ref. vars : 0.02 ( 0%) usr 0.00 ( 0%) sys 0.03 ( 0%) wall 422 kB ( 0%) ggc
tree PTA : 0.27 ( 3%) usr 0.00 ( 0%) sys 0.33 ( 3%) wall 2279 kB ( 1%) ggc
tree PHI insertion : 0.02 ( 0%) usr 0.00 ( 0%) sys 0.00 ( 0%) wall 325 kB ( 0%) ggc
tree SSA rewrite : 0.04 ( 0%) usr 0.00 ( 0%) sys 0.06 ( 0%) wall 5069 kB ( 2%) ggc
tree SSA other : 0.02 ( 0%) usr 0.03 ( 1%) sys 0.06 ( 0%) wall 547 kB ( 0%) ggc
tree SSA incremental : 0.15 ( 2%) usr 0.03 ( 1%) sys 0.17 ( 1%) wall 819 kB ( 0%) ggc
tree operand scan : 0.12 ( 1%) usr 0.08 ( 3%) sys 0.25 ( 2%) wall 16876 kB ( 5%) ggc
dominator optimization: 0.07 ( 1%) usr 0.02 ( 1%) sys 0.04 ( 0%) wall 2663 kB ( 1%) ggc
tree SRA : 0.04 ( 0%) usr 0.01 ( 0%) sys 0.02 ( 0%) wall 94 kB ( 0%) ggc
tree CCP : 0.07 ( 1%) usr 0.00 ( 0%) sys 0.06 ( 0%) wall 2507 kB ( 1%) ggc
tree PHI const/copy prop: 0.01 ( 0%) usr 0.00 ( 0%) sys 0.00 ( 0%) wall 7 kB ( 0%) ggc
tree split crit edges : 0.00 ( 0%) usr 0.00 ( 0%) sys 0.02 ( 0%) wall 991 kB ( 0%) ggc
tree reassociation : 0.02 ( 0%) usr 0.00 ( 0%) sys 0.02 ( 0%) wall 888 kB ( 0%) ggc
tree PRE : 0.15 ( 2%) usr 0.02 ( 1%) sys 0.15 ( 1%) wall 3586 kB ( 1%) ggc
tree FRE : 0.07 ( 1%) usr 0.01 ( 0%) sys 0.14 ( 1%) wall 2627 kB ( 1%) ggc
tree code sinking : 0.00 ( 0%) usr 0.00 ( 0%) sys 0.03 ( 0%) wall 470 kB ( 0%) ggc
tree linearize phis : 0.02 ( 0%) usr 0.00 ( 0%) sys 0.02 ( 0%) wall 17 kB ( 0%) ggc
tree forward propagate: 0.02 ( 0%) usr 0.00 ( 0%) sys 0.03 ( 0%) wall 878 kB ( 0%) ggc
tree phiprop : 0.01 ( 0%) usr 0.00 ( 0%) sys 0.00 ( 0%) wall 24 kB ( 0%) ggc
tree conservative DCE : 0.03 ( 0%) usr 0.04 ( 2%) sys 0.04 ( 0%) wall 27 kB ( 0%) ggc
tree aggressive DCE : 0.12 ( 1%) usr 0.01 ( 0%) sys 0.15 ( 1%) wall 7686 kB ( 2%) ggc
tree DSE : 0.08 ( 1%) usr 0.00 ( 0%) sys 0.03 ( 0%) wall 285 kB ( 0%) ggc
PHI merge : 0.00 ( 0%) usr 0.01 ( 0%) sys 0.01 ( 0%) wall 44 kB ( 0%) ggc
tree loop bounds : 0.00 ( 0%) usr 0.01 ( 0%) sys 0.01 ( 0%) wall 33 kB ( 0%) ggc
tree loop invariant motion: 0.01 ( 0%) usr 0.00 ( 0%) sys 0.00 ( 0%) wall 0 kB ( 0%) ggc
complete unrolling : 0.00 ( 0%) usr 0.00 ( 0%) sys 0.01 ( 0%) wall 1000 kB ( 0%) ggc
tree vectorization : 0.02 ( 0%) usr 0.00 ( 0%) sys 0.02 ( 0%) wall 686 kB ( 0%) ggc
tree slp vectorization: 0.06 ( 1%) usr 0.00 ( 0%) sys 0.07 ( 1%) wall 4623 kB ( 1%) ggc
tree iv optimization : 0.02 ( 0%) usr 0.00 ( 0%) sys 0.00 ( 0%) wall 671 kB ( 0%) ggc
predictive commoning : 0.01 ( 0%) usr 0.00 ( 0%) sys 0.01 ( 0%) wall 58 kB ( 0%) ggc
tree loop init : 0.00 ( 0%) usr 0.00 ( 0%) sys 0.01 ( 0%) wall 824 kB ( 0%) ggc
tree NRV optimization : 0.01 ( 0%) usr 0.00 ( 0%) sys 0.02 ( 0%) wall 18 kB ( 0%) ggc
tree rename SSA copies: 0.03 ( 0%) usr 0.00 ( 0%) sys 0.02 ( 0%) wall 0 kB ( 0%) ggc
dominance frontiers : 0.01 ( 0%) usr 0.01 ( 0%) sys 0.01 ( 0%) wall 0 kB ( 0%) ggc
dominance computation : 0.27 ( 3%) usr 0.04 ( 2%) sys 0.23 ( 2%) wall 0 kB ( 0%) ggc
control dependences : 0.00 ( 0%) usr 0.01 ( 0%) sys 0.01 ( 0%) wall 0 kB ( 0%) ggc
expand : 0.93 (11%) usr 0.34 (13%) sys 1.18 (10%) wall 22542 kB ( 7%) ggc
varconst : 0.02 ( 0%) usr 0.00 ( 0%) sys 0.03 ( 0%) wall 456 kB ( 0%) ggc
jump : 0.00 ( 0%) usr 0.01 ( 0%) sys 0.00 ( 0%) wall 351 kB ( 0%) ggc
forward prop : 0.08 ( 1%) usr 0.01 ( 0%) sys 0.10 ( 1%) wall 1368 kB ( 0%) ggc
CSE : 0.13 ( 2%) usr 0.00 ( 0%) sys 0.12 ( 1%) wall 162 kB ( 0%) ggc
dead code elimination : 0.03 ( 0%) usr 0.00 ( 0%) sys 0.05 ( 0%) wall 0 kB ( 0%) ggc
dead store elim1 : 0.11 ( 1%) usr 0.00 ( 0%) sys 0.05 ( 0%) wall 612 kB ( 0%) ggc
dead store elim2 : 0.13 ( 2%) usr 0.00 ( 0%) sys 0.09 ( 1%) wall 932 kB ( 0%) ggc
loop analysis : 0.02 ( 0%) usr 0.00 ( 0%) sys 0.01 ( 0%) wall 503 kB ( 0%) ggc
loop invariant motion : 0.01 ( 0%) usr 0.01 ( 0%) sys 0.01 ( 0%) wall 67 kB ( 0%) ggc
CPROP : 0.13 ( 2%) usr 0.00 ( 0%) sys 0.10 ( 1%) wall 1024 kB ( 0%) ggc
PRE : 0.01 ( 0%) usr 0.00 ( 0%) sys 0.02 ( 0%) wall 118 kB ( 0%) ggc
CSE 2 : 0.09 ( 1%) usr 0.02 ( 1%) sys 0.05 ( 0%) wall 221 kB ( 0%) ggc
branch prediction : 0.03 ( 0%) usr 0.02 ( 1%) sys 0.06 ( 0%) wall 1578 kB ( 1%) ggc
combiner : 0.10 ( 1%) usr 0.00 ( 0%) sys 0.08 ( 1%) wall 679 kB ( 0%) ggc
if-conversion : 0.01 ( 0%) usr 0.00 ( 0%) sys 0.06 ( 0%) wall 953 kB ( 0%) ggc
regmove : 0.02 ( 0%) usr 0.00 ( 0%) sys 0.02 ( 0%) wall 1 kB ( 0%) ggc
integrated RA : 0.35 ( 4%) usr 0.00 ( 0%) sys 0.34 ( 3%) wall 4128 kB ( 1%) ggc
reload : 0.20 ( 2%) usr 0.01 ( 0%) sys 0.31 ( 3%) wall 2554 kB ( 1%) ggc
reload CSE regs : 0.11 ( 1%) usr 0.00 ( 0%) sys 0.13 ( 1%) wall 1551 kB ( 0%) ggc
load CSE after reload : 0.01 ( 0%) usr 0.00 ( 0%) sys 0.01 ( 0%) wall 1 kB ( 0%) ggc
thread pro- & epilogue: 0.03 ( 0%) usr 0.00 ( 0%) sys 0.08 ( 1%) wall 3980 kB ( 1%) ggc
if-conversion 2 : 0.01 ( 0%) usr 0.00 ( 0%) sys 0.01 ( 0%) wall 456 kB ( 0%) ggc
combine stack adjustments: 0.00 ( 0%) usr 0.00 ( 0%) sys 0.01 ( 0%) wall 0 kB ( 0%) ggc
peephole 2 : 0.01 ( 0%) usr 0.00 ( 0%) sys 0.05 ( 0%) wall 124 kB ( 0%) ggc
hard reg cprop : 0.06 ( 1%) usr 0.00 ( 0%) sys 0.05 ( 0%) wall 31 kB ( 0%) ggc
scheduling 2 : 0.42 ( 5%) usr 0.02 ( 1%) sys 0.36 ( 3%) wall 630 kB ( 0%) ggc
machine dep reorg : 0.04 ( 0%) usr 0.00 ( 0%) sys 0.04 ( 0%) wall 6 kB ( 0%) ggc
reorder blocks : 0.04 ( 0%) usr 0.00 ( 0%) sys 0.06 ( 0%) wall 919 kB ( 0%) ggc
final : 0.05 ( 1%) usr 0.00 ( 0%) sys 0.10 ( 1%) wall 1187 kB ( 0%) ggc
symout : 0.02 ( 0%) usr 0.01 ( 0%) sys 0.04 ( 0%) wall 148 kB ( 0%) ggc
plugin execution : 0.18 ( 2%) usr 0.32 (12%) sys 0.43 ( 4%) wall 0 kB ( 0%) ggc
TOTAL : 8.48 2.64 12.15 315665 kB
关于performance - 代码生成时间，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/7829075/